Are You a Night Owl? Delayed Sleep Phase Syndrome Overview

By Brandon Peters, MD

Night owls rule the evening roost. What explains the natural desire to stay up late and sleep in, especially in teenagers? With this overview, discover the causes, symptoms, diagnostic testing, and treatments of delayed sleep phase syndrome. Consider the consequences, including insomnia and sleep deprivation, and what can be done to keep the condition in check.

What Is a Night Owl?

First, how is a night owl defined? Anyone who stays up later than most may be viewed as a potential suspect. However, those with delayed sleep phase syndrome may be birds of a different feather.

If the natural tendency to fall asleep is delayed by at least several hours compared to the average person, with a sleep onset closer to 1 to 3 a.m., this fits the bill. In some cases, the delay may be even more extreme, with a night owl going to sleep closer to sunrise.

The desire to wake up is similarly delayed by at least several hours. Someone who is characterized as a night owl may not desire to wake until 10 a.m. or later. With a sleep onset closer to sunrise, the affected person may not desire to wake until into the early afternoon.

How Common Is Delayed Sleep Phase Syndrome?

It is estimated that 10 percent of the population could be characterized as night owls with delayed sleep phase syndrome. It may be more common among teenagers, who are susceptible to a slight delay in their sleep timing, but it can persist throughout life. There are many retired people who experience the condition once the alarm clock is silenced!

What Causes a Delayed Sleep Phase?

There seems to be a genetic predisposition towards developing delayed sleep phase syndrome. Some of this science is understood. For example, a mutation in the CRY1 gene alters the human circadian clock, delaying sleep by 2 to 2 1/2 hours compared to non-carriers. There will likely be more genes identified that have a role. 

Approximately 40 percent of people with delayed sleep phase syndrome report a family history of the condition.

Beyond genetic programming, there are environmental factors that may unmask the condition. Most importantly, light has powerful effects on the timing of the circadian system. It may provoke the delay in sleep timing, and may also be used to correct the condition.

Understanding the Circadian System and Sleep

Sleep is dependent on two processes: sleep drive and the circadian alerting system. If isolated in a constant environment, like a cave, the genetically determined circadian timing will become evident. It is controlled by the suprachiasmatic nucleus, a region of cells in the hypothalamus of the brain, and highly influenced by light exposure. Every cell, and organ, in the body follows a circadian pattern.

For most people, this internal clock is programmed to run a little long, perhaps resetting every 24 1/2 hours. In the cave, without exposure to light variance, an isolated person would naturally fall asleep and wake 30 minutes later, shifting later each and every day. In a week, the timing of sleep would move 3 1/2 hours. In a month, it would shift 14 hours, so that the person would want to sleep during the natural day and be awake in the natural night. This natural drift in the circadian timing is reset with morning sunlight.

Exposure to natural light in the early morning hours is a signal to the brain for wakefulness. It makes it easier to wake. It also slightly shifts the timing of sleep earlier, making it easier to fall asleep. This helps to align the desire for sleep to the natural period of darkness overnight. Without it, significant problems can develop with sleep and health.

What Are the Symptoms of Delayed Sleep Phase Syndrome?

People with delayed sleep phase syndrome will generally experience two symptoms: insomnia and sleepiness. Why would these seemingly contradictory symptoms occur in the same person? Again, it comes back to a question of when—it comes back to timing. 

Insomnia

Most night owls will experience significant insomnia if they attempt to go to bed earlier than their natural desire for sleep onset. Crawling into bed at 10 p.m. may result in hours of lying awake, tossing and turning. This can provoke anxiety, frustration, and anger—feelings that make the insomnia worse. When left to stay up late on weekends or during vacation breaks, it suddenly becomes much easier to fall asleep.

Morning sleepiness

In the early morning hours, it can be difficult to wake a night owl. It’s like trying to wake the dead. Teenagers have to be dragged out of bed, splashed with water, or roused with threats from despondent parents. This morning sleepiness can be profound. Depending on the hour, it is akin to waking someone with normal sleep timing in the middle of the night. It is extremely difficult to wake and function. By midday, however, the sleepiness abates. When the late evening rolls around, the night owl feels very awake, repeating the cycle again.

Social Pressure Leads to Sleep Deprivation

Unfortunately, night owls are not typically allowed to sleep and wake when their bodies tell them to. If they could always go to bed at 2 a.m. and wake at 10 a.m., there would be no sleep problem. They would fall asleep easily, without insomnia, and wake easily without conflict. Unfortunately, pressure from the rest of society—parents, spouses, bosses, school systems—may be quite disruptive. Without accommodation, chronic tardiness and absenteeism can lead to educational and professional dysfunction.

If someone does not naturally fall asleep until 2 a.m., but has to wake at 6 a.m. to be to work on time, sleep deprivation inevitably results. Unfortunately, 4 hours of sleep is not enough to meet even basic sleep needs. This can have profound effects on health and well-being. Consider some of the symptoms associated with sleep deprivation:

• Sleepiness

• Fatigue

• Difficulty concentrating

• Memory problems

• Mood changes (depression, anxiety, or irritability)

• Errors or accidents

• Physical pain

• Hallucinations

• Paranoia

There is some evidence this can be fatal. This is likely due to the chronic effects of sleep deprivation. One study suggests that people with delayed sleep phase syndrome have a 10 percent higher risk of dying compared to controls.

How Is Delayed Sleep Phase Diagnosed?

With proper education, it becomes fairly easy to recognize night owls who are likely experiencing delayed sleep phase syndrome. It may be a lifelong affliction, starting in adolescence and persisting for decades. How can it be diagnosed?

Fortunately, testing is not required to reach a diagnosis. A careful history by a board-certified sleep physician can typically identify the condition. In some cases, sleep logs kept over weeks may aid the recognition. Rarely is testing with actigraphy needed.

In research settings, the measurement of melatonin levels can help to identify the circadian timing. In particular, the dim light melatonin onset (DLMO) measured via blood or saliva can establish the pattern. Unfortunately, the repeated sampling requires a carefully controlled laboratory environment. This is virtually never done in a clinical practice. More recently, a blood test called TimeSignature has been developed, but it is not widely available.

Treatments of Delayed Sleep Phase Syndrome: Light, Melatonin, and More

If a condition is genetically determined, and potentially lifelong, it may seem like a life sentence. Fortunately, for delayed sleep phase syndrome, this is not the case! There are some effective ways to keep the timing of sleep in a normal phase. It may require a little extra effort, but consider these potential helpful interventions:

Sleep schedule consistency

There is good evidence that night owls can maintain a socially acceptable sleep timing. This requires consistency, especially in regard to the wake time. Get up at the same time every day, including weekends. Do not sleep in. Go to bed feeling sleepy, even if this initially requires a delay in the preferred bedtime. This will make it easier to fall asleep faster, relieve pressure to sleep, and reinforce the sleep quality.

Morning sunlight

It is especially important to reset the timing of sleep with morning sunlight. This is most effective immediately upon awakening. Try to go outside for 15 to 30 minutes upon awakening. Wake with an alarm, throw on clothes, and immediately get outside. Take a walk. Read the newspaper in the garden. Check social media while facing the sunrise. Light should hit the eyes, but don’t stare directly into the sun. Even a cloudy or rainy day, try to stick to the routine. In winter months, a light box may be necessary for phototherapy. The effects may take up to 1 month to become evident.

Avoid light at night

Artificial screen light should be minimized at night, especially in the hours preceding bedtime. It may shift the timing of sleep to occur later, causing insomnia and morning sleepiness. Devices may be switched to night mode, cutting out the blue light that can shift sleep timing. Blue blocker sunglasses (with an amber tint) or screen covers may be employed. Best yet, simply shut down the electronics in the 2 hours before bedtime. The buffer zone before the goal bedtime should be spent relaxing.

Melatonin

Melatonin is a hormone produced overnight by the pineal gland in the brain. It can be an external signal to the circadian system, most effective among the blind. If taken up to 6 hours before the desired bedtime, it may help night owls to fall asleep earlier. The effects may be somewhat weak, and certainly overpowered by the effects of light.

Cognitive behavioral therapy for insomnia (CBTI)

This effective treatment helps to improve the patterns of sleep and one’s relationship to it. Sleep consolidation, stimulus control, mindfulness, and relaxation techniques may be integrated into a program. It may be guided with help from a psychologist, class, online course, or book.\

Chronotherapy

Rarely, it may be necessary to adjust the timing of sleep incrementally in a structured environment. It is difficult to carry out at home and may require hospitalization. Over successive days, the sleep period may be delayed by 1 to 2 hours until the desired timing of sleep is achieved. Poorly timed light may complicate the efforts, and strict adherence to the final schedule must be observed.

Prescription medications

Sleeping pills and stimulant medication to enhance alertness have a limited role in this condition. Generally, they will be weakly effective. As a result, they may be overused and even abused. The risk of overdose in night owls, especially when these medications are used in combination with alcohol, is high. Instead of masking symptoms with a drug, the underlying timing of the circadian rhythm should be corrected.

Social awareness

Education may help parents to appreciate what their teenager is experiencing, to know that it is not laziness or defiance. High schools should continue to accommodate this natural timing among their students by shifting the school day. Later school start times enhance academic performance, reduce tardiness and truancy, and even diminish car accidents among teens. 

Conclusion

Sleep deprivation can have serious impacts on health and well-being. If you are struggling with delayed sleep phase syndrome, consider seeking the guidance of a board-certified sleep physician. Start with some simple advice: Go to bed feeling sleepy (even if later), keep a consistent wake time, and get sunlight upon awakening. If more help is needed, seek it out.

How the Best Sunrise Alarm Clocks Make Waking Easier

By Brandon Peters, MD

It is pretty normal to use an alarm clock to wake up. What is not as common, however, is for the clock to mimic a sunrise and wake you with a gradually increasing amount of light. How do the best sunrise alarm clocks make waking easier? Learn how a dawn simulation light works, why it might be preferable to an audible alarm, who benefits most from its use, and what alternatives exist that may help to enforce a circadian pattern, easing insomnia and making it easier to wake and get up.

What Is a Sunrise Alarm Clock?

A sunrise alarm clock, or dawn simulation light, is an artificial light source that is integrated into a standard digital clock. It is timed to gradually wake a person at a selected time. It does this by mimicking the steadily increasing light of sunrise, often over 30 to 40 minutes, but some models may allow the timer to be adjusted from 15 to 60 minutes.

These simulators may have a full-spectrum white or yellow LED lightbulb. The color spectrum, or color temperature (think of this as the “warmth”), of this light may vary slightly from one model to the next. Most are of modest intensity, often 100 to 300 lux, with less light than a standard light box.

There are a variety of models, most costing less than $25 to $100, including:

• Philips Wake-Up Light HF3520

• Philips HF3505

• Philips Somneo HF3650

• hOmeLabs Sunrise Alarm Clock

• Mosche Sunrise Alarm Clock

• INLIFE Wake Up Light Alarm Clock

• NATPLUS Sunrise Alarm Clock

• iHome Zenergy Bedside Sleep Therapy Machine

• totobay

• Sharp Sunrise Simulator

• Lumie

The add-on features also vary widely from one product to the next. Many have the ability to adjust the light intensity, snooze features, and associated standard alarm sounds or music. There may be USB ports integrated for charging devices. Beyond encouraging a gradual awakening, some can even dim light gradually (a so-called sunset feature), making it feel more natural to fall asleep.

How Do Dawn Simulation Lights Work?

Dawn simulation lights can make it easier to wake, but how do these devices work? It is important to consider the natural patterns of light and darkness and how the circadian rhythm enforces optimal sleep and wakefulness.

Humans, like most animals, have evolved to sleep overnight during darkness. Light, conversely, has a waking effect on the brain and body. It suppresses melatonin and activates the circadian alerting signal. Light at the wrong time, like from a screen prior to bedtime, may make it hard to fall asleep and contribute to insomnia. In the morning, when incorporated into a sunrise alarm clock, it may make it easier to wake.

Light exerts this impact by traveling from the eyes via the optic nerves to an area of the brain that regulates the body’s circadian rhythm. This area of the brain, called the suprachiasmatic nucleus, lies in the hypothalamus. It is the master clock of the body. Without it, the patterns of sleep and wakefulness, metabolism, hormone release, cortisol levels, body temperature, and other processes would run amok.

Fortunately, light at the proper time may help us to sleep and feel better. Even artificial light, if appropriately timed, may enforce the normal patterns of our body that would exist if we slept in a perfectly natural environment. A gradual increase of light in the morning hours, even in the natural darkness present in winter months at northern latitudes, may reinforce a normal pattern of waking.

Why Is Light Better Than Sound?

The sudden, blaring sound of an alarm clock will definitely wake someone. However, this abrupt shift from sleep to wakefulness can be disorienting. If full wakefulness is not attained, the snooze button may be pressed and sleep may quickly resume. Short awakenings, such as those lasting less than 5 minutes, may go unremembered. If the alarm clock is simply turned off—or smashed into 1,000 pieces—trouble may ensue!

Light may wake a person more gently and more gradually. The transition from sleep to wakefulness is more orderly. This may help to relieve sleep inertia, that profound sense of sleepiness that is difficult to shake when first opening your eyes. It is something that feels more natural. The sky does not go from pitch black to glaring sunshine. As the sun creeps over the horizon, the amount of light hitting our eyes (even through closed eyelids) steadily increases. It may reach a threshold where it finally wakes us. This may make it less likely a person would want to hit snooze repeatedly and fall back asleep. Even the thought of it seems more pleasant.

Who Should Consider a Sunrise Alarm?

Although there are certain groups who may benefit more from using a sunrise alarm, scientific research suggests that many of us could yield positive health impacts.

There are a surprising number of important benefits from the use of dawn simulation lights. Research suggests it may:

• Improve cardiac function and reduce the risk of heart attacks

• Provide a boost to the brain’s function (in select cognitive domains)

• Enhance performance in tasks done immediately after waking

Clearly there are certain conditions or groups of people who would likely enjoy the effects of a sunrise alarm even more. Consider these possibilities:

Night owls

Delayed sleep phase syndrome is a circadian disorder characterized by difficulty initiating sleep (insomnia) and profound morning sleepiness. It affects 10 percent of the population, usually starting in the teenage years. Most night owls feel naturally sleepy close to 2 a.m. and may not naturally wake until 10 a.m. The use of a dawn simulation light may make waking a little easier. In some cases, a light box may be more effective to reinforce an earlier circadian phase.

Winter depression

Seasonal affective disorder, or winter depression, impacts people living in northern latitudes during the winter months when the nights are long and the days are short. Darkness can make it hard to wake in the morning. This may lead to increased depressive symptoms, lethargy, prolonged sleep, weight gain, and other symptoms. An artificial light may help the morning to start a little easier.

Teenagers

As noted above, teenagers are susceptible to delayed sleep phase syndrome. As a general rule, teens are more likely to have a slight delay in sleep timing, even with a less profound shift in the pattern. This can make it hard for adolescents to fall asleep at a desirable time. It can also make it very difficult to wake them in the morning. This can lead to early morning fights with parents, tardiness, absenteeism, and other problems like car accidents, inattention, and academic failure. Consider how desirable it might be to have a gentle light do the waking, and let the drama of the morning fade away.

Shift workers

Those who work atypical shifts—second, third, graveyard, rotating, or even call coverage—are subject to many sleep problems. When the desire for sleep and wake is forcibly misaligned from the patterns of darkness and light, it can be difficult to function optimally. This may lead to increased errors, accidents, and health problems (including a higher risk for cardiovascular disease, weight gain, and breast and colorectal cancers). Artificial light, if properly timed, may help to alleviate some of this misalignment.

Jet lag 

For every one time zone crossed, it can take one day to adjust the circadian rhythm. Traveling across a continent, or an ocean, can lead to significant disruption. The use of a sunrise alarm clock may make this transition easier. The optimal timing of this light exposure will depend on the distance traveled, and whether preparation was made prior to departing on the trip.

Hearing impaired

Finally, those with a hearing impairment may benefit from using a light to wake, rather than an audible alarm. The deaf may otherwise need to rely on others to wake on time. The use of a sunrise alarm clock may provide a new degree of independence.

Alternatives to Sunrise Alarm Clocks

Many people will be attracted to the possibility of easing insomnia and waking and getting up easier. Not everyone may want to use a sunrise alarm clock, however. There may be a handful of alternatives to consider. Consider how these additional options may make it easier to wake in the morning:

Natural sunlight

Throw the window shades open in your bedroom before retiring for the evening. This will let in natural light. After sunrise, the light will be able to stream through the windows and promote wakefulness. Unfortunately, this may not be ideally timed certain times of the year.

Light box

Consider a light box with 10,000 lux of intensity. It is powerful enough to shift the circadian rhythm, benefiting seasonal affective disorder as well.

Light therapy glasses

For those with a little extra buying power, light therapy glasses are a convenient and effective option. With a lower amount of light, shone directly into the eyes, these glasses can make it easier to wake.

Caffeine

A cup of coffee or tea can make it easier to get the morning started. Caffeine blocks adenosine, a signal for sleep, within the brain. With a half-life of 4 to 6 hours, it can get you through the morning.

Get motivated

Consider ways to motivate yourself out of bed. Morning exercise, quickly hopping in the shower, a special breakfast, or stepping outside to enjoy the early light may be helpful. In some cases, scheduling something you really enjoy for first thing in the morning may do the trick. 

Conclusion

There are many effective ways to wake and feel refreshed. A sunrise alarm clock may help to ease the transition to wakefulness. If you consistently struggle to wake, or have sleep of poor quality, consider getting evaluate by a board-certified sleep physician. Sleep disorders can be effectively resolved to the benefit of your health and well-being.

Sources:

Follum JD, Catchpole JM. “Sunrise alarm clock for the hearing impaired.” Biomed Sci Instrum. 2011;47:18-23.

Viola AU et al. “Dawn simulation light: a potential cardiac events protector.” Sleep Med. 2015 Apr;16(4):457-61. doi: 10.1016/j.sleep.2014.12.016. Epub 2015 Feb 26.

Gabel V et al. “Dawn simulation light impacts on different cognitive domains under sleep restriction.” Behav Brain Res. 2015 Mar 15;281:258-66. doi: 10.1016/j.bbr.2014.12.043. Epub 2014 Dec 27.

Thompson A et al. “Effects of dawn simulation on markers of sleep inertia and post-waking performance in humans.” Eur J Appl Physiol. 2014 May;114(5):1049-56. doi: 10.1007/s00421-014.2831-z. Epub 2014 Feb 11.

Why Does Insomnia Happen?

By Brandon Peters, MD

There are few things more frustrating than an inability to sleep. Insomnia may undermine your night’s rest, leading to important daytime consequences. Why does insomnia happen? Learn about the factors that may lead to an inability to sleep at night and consider what you might do about them.

Insomnia is defined as the inability to fall or stay asleep or sleep that is unrefreshing in the absence of another sleep disorder (such as sleep apnea). It is the most common of all the various sleep disorders, and it may be a significant problem in about 1 in 4 people. Nearly everyone has experienced some degree of insomnia, even if only transiently, but why does this occur?

Spielman’s theoretical model of insomnia underpins our current understanding of the disorder. This theory suggests that three things contribute to the development of chronic insomnia, including: predisposing, precipitating, and perpetuating factors.

Predisposition: The Threshold for Insomnia

It is believed that everyone has the capacity to develop difficult sleeping at night. This predisposition is likely genetically determined. Some of the contributions to it likely include our individual circadian rhythm, homeostatic sleep drive, and level of arousal. The circadian rhythm directs the timing of our sleep, and it may be either advanced or delayed in some people. The homeostatic sleep drive is dependent on the build of sleep-promoting chemicals, including the compound called adenosine. The longer we stay awake, the sleepier we become, due in part to these chemicals. Finally, the baseline level of arousal also is factored in. Some people are more “wired” – also likely due to varying levels of neurotransmitters that promote wakefulness – and this may make sleep disruption more likely.

The predisposition towards insomnia can be thought of as a threshold. Below the threshold at which insomnia will develop, you sleep fine. Given the proper scenario, however, and the balance tips toward sleep disruption. The things that provoke the development of insomnia are known as the precipitating factors.

The Precipitating Factors for Insomnia

What might cause insomnia? There will be some variability in what provokes insomnia in you. Triggers for insomnia may not be the same for every person. Something that is particularly disruptive to your sleep may have no effect on someone else’s. This varying sensitivity is normal, and it shouldn’t be a source of additional distress.

Some of the most common triggers for insomnia include stress, mood disorders, pain, substance use, and poor sleep environment. Stress of every imaginable type is highly likely to make it difficult to sleep. The night before a big examination or presentation at work may be fitful. Major life events such as moving, the loss of a job, relationship problems including divorce, or the death of a close friend or relative may also lead to insomnia. If these problems lead to anxiety or depression, the risk of insomnia may be compounded.

There are other causes of insomnia as well. In particular, chronic medical conditions, especially those that cause pain, may disrupt sleep. Sleep is usually an anesthetic state, in which pain is not sensed, but nevertheless pain can make it hard to fall asleep. There are certain substances that may contribute to difficulty falling or staying asleep as well. The most common, caffeine, is notorious for sleep disruption. Nicotine is another stimulating substance that disrupts sleep. Alcohol may cause drowsiness initially, but when it starts to wear off, sleep becomes fragmented. Other medications and drugs can also undermine sleep.

Finally, the sleep environment can also make it hard to sleep. If your bedroom is too warm or too cold, too bright, or too noisy, sleep may be fleeting. An uncomfortable bed, or none at all, may also cause insomnia. If someone is snoring nearby, or a baby cries out to be fed, sleep becomes light and fragmented. Studies have also shown that environmental noise, such as may be present in a busy city, can also disrupt sleep.

It should also be noted that working against your natural ability to sleep can also cause insomnia. If you try to sleep at a time that your body expects you to be awake (contradicting your circadian rhythm), you will likely lie awake. If you took a prolonged nap in the afternoon, your desire for sleep will be diminished due to a weakened sleep drive. In addition, if you are wound up after a fight with your spouse (with increased arousal), insomnia will likewise result.

Perpetuating an Inability to Sleep

Once your threshold for insomnia has been crossed, incited by one of the precipitating factors, you will find yourself lying awake at night. This may quickly pass, as occurs in acute insomnia. If you had insomnia due to an examination that has come and gone, for example, the difficulty sleeping goes away with it. However, there are scenarios where insomnia will persist, and unintentional behavioral or cognitive changes may actually make things worse.

If the precipitating factor has not resolved, it is very likely that it will continue to disrupt your sleep. It is possible to adapt to some of these triggers, depending on the nature of the disruption, but this may not always happen. Therefore, it can be important to identify the cause of the insomnia and try to resolve it. This will require a careful self-assessment of the factors that are important to your situation.

Unfortunately, some triggers are not easily remedied. It may require a tincture of time to grieve a death. A mood disorder may require medication or psychotherapy. A new baby may take months to sleep through the night. Focus on what you have control over, and avoid making things worse.

Many people with insomnia unintentionally make their insomnia more sustained. Several bad nights of sleep (or dozens, for that matter) may lead you to change your pattern of sleep. This can be particularly true if you find yourself waking and lying awake in the night. You may think, “I am not sleeping well, so I am going to go to bed earlier to try to get enough sleep.” By extending your time in bed, you have introduced a new problem: you are now going to bed earlier than your body wants you to. If your body says you will get sleepy at 11 PM, but you crawl into bed at 9 PM, guess what happens? You will now have trouble falling asleep as well.

There can be a lot of emotions and thoughts that become associated with insomnia. Chronic insomnia is deeply frustrating. Feelings of distress, hopelessness, inadequacy, and failure become part of the scenario. People who sleep well do not wake in the morning and assess how well they slept. Insomniacs often do. Sleep becomes a focus in insomnia, and when it does, it becomes a challenge. There can also be an element of catastrophization, in which the worst possible scenario is imagined during the periods of wakefulness: “If I don’t get enough sleep, I’m going to get fired.” Many of these thoughts and feelings must be defused, and cognitive behavioral therapy for insomnia (CBTI) can be very helpful in this regard.

It is clear that insomnia can happen for multiple reasons, as detailed above. Everyone has a specific threshold at which insomnia will develop. The precipitating factors will vary for each person, but there are common triggers related to stress, mood, pain, and substance use. Acute insomnia becomes chronic when behaviors, thoughts, and emotions change surrounding sleep. If you find yourself stuck in the pattern of insomnia, it can be helpful to speak to a sleep specialist to begin to make changes that can correct the problem. Insomnia can be treated effectively, so reach out to get the help that you need.

Source:

Kryger, MH et al. “Principles and Practice of Sleep Medicine.” Elsevier, 5th edition. 2011.

The Science of Circadian Rhythms

By Brandon Peters, MD

Circadian rhythms may be the most difficult concept to understand in the world of sleep medicine. There is a lot of confusing language, and it relies on science that is not easily approached. Fortunately, a basic understanding of the science of circadian rhythms can be obtained and may help to explain some cases of insomnia and daytime sleepiness.

As the World Turns

The Earth’s 23 hour and 56 minute daily rotation provides predictable rhythms of light and temperature, food, and predator activity. Through adaptive evolution, our body’s metabolism and even our behaviors are programmed to respond to this precise timing. Franz Halberg coined the term circadian (from the Latin meaning “about a day”) in 1959. It describes numerous approximately 24-hour cycles that are generated within nearly every organism on the planet.

Within our body, there is a system in place that measures time and synchronizes many internal processes to daily events within the environment. Some of these important processes include:

• Sleep and wakefulness

• Metabolism

• Core body temperature

• Cortisol levels

• Melatonin levels

• Other hormones (growth hormone, thyroid hormone, etc.)

The control of these patterns is built into our genetic makeup; the machinery synchronizes rhythms that will persist independently of outside influences. The first mammalian gene, Clock, was identified in 1994. Multiple additional genes have been identified that constitute a core molecular clock that gives rise to other cellular, tissue, and organ function.

Every cell in our body follows a circadian pattern: an extraordinary symphony of biochemical reactions that are perfectly timed based on available resources and orchestrated by a small group of cells in the anterior part of the brain’s hypothalamus. Through hormones and other as yet undetermined influences, the central pacemaker coordinates peripheral clocks that are present in cells as diverse as cardiac, liver, and adipose tissues.

Light is perceived by the eyes and travels via the retina to the optic nerves. Above the optic chiasm, where the two optic nerves cross behind the eyes, sits the suprachiasmatic nucleus (SCN). This is the master clock of the body. It couples the numerous physiological processes described to the timing of light and darkness in the environment.

These patterns will persist without external time cues, but they may vary slightly from the geological day length. As a result, in isolation from resetting cues, the timing of these processes may gradually become desynchronized. The degree of shift may depend on our genetic program, or tau, with most people having an internal clock that runs longer than 24 hours. It is understood that our genetics and the interaction with other environmental factors – especially the exposure to morning sunlight – may have important effects on resetting the internal clock. These external influences are called zeitgebers, from the German for “time-givers”.

When the internal clock is misaligned to our environment, circadian disorders such as delayed and advanced sleep phase syndrome can occur. With a complete disconnect from light perception, as occurs in total blindness, a Non-24 rhythm occurs. These conditions are often associated with insomnia and excessive daytime sleepiness as well as irregularities in the sleep-wake rhythm that cause social and occupational dysfunction.

Fortunately, treatment of circadian disorders can be highly effective and a board-certified sleep physician can provide helpful guidance and resources.

Sources:

Borbely, AA. “A two process model of sleep regulation.” Hum Neurobiol. 1982;1:195-204.

Czeisler, CA et al. “Bright light resets the human circadian pacemaker independent of the timing of the sleep-wake cycle.” Science. 1986;233:667-671.

Lewy, AJ et al. “Phase shifting the human circadian clock using melatonin.” Behav Brain Res. 1996;73:131-134.

Moore RY and Eichler, VB. “Loss of a circadian adrenal corticosterone rhythm following suprachiasmatic lesions in the rat.” Brain Res. 1972 Jul 13;42(1):201-206.

Moore-Ede, MC et al. “A physiological system measuring time, “ in The Clocks That Time Us. Cambridge, Massachusetts, Harvard University Press, 1984, p. 3.

Peters, BR. “Irregular Bedtimes and Awakenings.” Evaluation of Sleep Complaints. Sleep Med Clinic. 9(2014)481-489.

Piggins, HD. “Human clock genes.” Ann Med. 2002;34(5)394-400.

Reid, KJ and Zee, PC. “Circadian disorders of the sleep-wake cycle,” in Principles and Practices of Sleep Medicine. Edited by Kryger MH, Roth T, Dement WC. St. Louis, Missouri, Elsevier Saunders, 2011, pp. 470-482.

Richardson, G and Malin, HV. “Circadian rhythm sleep disorders: pathophysiology and treatment.” J Clin Neurophysiol. 1996;13:17-31.

Sack, RL and Lewy, AJ. “Circadian rhythm sleep disorders: lessons from the blind.” Sleep Medicine Reviews. 2001;5(3):189-206.

Vitaterna, MH et al. “Mutagenesis and mapping of a mouse gene, Clock, essential for circadian behavior.” Science. 1994;264(5159):719-725.

How to Use Fitness Trackers for Sleep Improvement

By Brandon Peters, MD

If you have purchased a fitness tracker, like millions of others, you may wonder how to use the wearable device to improve your sleep. These sleep trackers may provide some valuable insight into an important of health and well-being. They can also be completely useless. What do these wearables measure? How accurate are these measurements? How do they differ from medical sleep studies? Importantly, how should the information collected be used to make changes to improve sleep and reduce insomnia? Let’s consider these important questions and discover how to use fitness trackers to sleep better.

What Sleep Metrics Do Wearable Fitness Trackers Measure?

There are many wearable devices available that can be used to track fitness goals and even sleep. Some of the most popular options include the FitBit and Apple Watch. There are also smartphone apps, smart beds, mattress pads, and stand-alone products that can track sleep metrics. What kind of information is collected?

Movement

Most devices are tracking movement. There are variations on actigraphy. This measures movement velocity and direction with an accelerometer. It may be assumed that stillness equates with sleep, and movement corresponds with activity.

Biometrics

Sophisticated devices may detect breathing patterns, heart rate, or oxygen levels. It may even be possible to measure electrical current conductivity within the skin. Sound may also be detected, sometimes via vibration, that may correspond with snoring.

Schedule

Timing is important to sleep quality. It may also be possible to input information about your bedtime, wake time, and even naps to help track sleep patterns over an extended period. This information is often collected via sleep logs and may help to identify circadian rhythm disorders.

Environmental Characteristics

Some devices may also be able to identify other environmental characteristics, such as lighting, temperature, and noise. These may be useful to support the other variables that are measured. If the room is dark, it is nighttime, and a person is not moving, it is more likely that they would be asleep.

How Accurate Are Sleep Trackers?

It is natural to wonder how accurate sleep trackers are in measuring the characteristics of sleep. If you were dieting and using a scale, you would certainly want to ensure the weight that it was reporting was close to reality, both true to the actual value (accuracy) and repeatable over time (precision).

Sleep is more than just lying still. Someone could lie perfectly still and a wearable may believe this inactivity corresponds to sleep. Similarly, movements may occur during sleep that do not necessarily correspond with complete wakefulness. Many awakenings will go unnoticed by an individual as it can take more than 5 minutes of wakefulness before a memory is generated.

It is possible that other measurements may help to strengthen the accuracy of these observations. Breathing becomes very regular in deep, slow-wave sleep. This may indicate a person has fallen asleep. Heart rate patterns, oxygen levels, and other biometric measurements may help improve accuracy.

Unfortunately, many sleep trackers are products that are designed for consumers without scientific validation. The measurements may not be either accurate or reproducible. Artifact may interfere with the measurements. Moreover, the collected information may not correspond to the gold standard measurements.

Comparing Information to Sleep Testing and Studies

When sleep is measured by a diagnostic polysomnogram in a sleep center, there are a number of important characteristics. These include the brain wave activity as measured by EEG, muscle tone, the movement of eyes, other body movements, and sometimes additional data. No fitness trackers are able to collect all of these data. The nightly sleep patterns they provide—showing light, deep, and even REM sleep—are not as accurate as the information gathered with formal sleep testing.

In fact, sleep trackers are perhaps closest to an actigraph, a small wristwatch-like device that measures movement to give a rough pattern of sleep and wakefulness. These data can be very difficult to interpret, even by expert researchers, and the messy signals may be inscrutable to an algorithm. What is a person to do? How can you use the data that is collected via a wearable sleep tracker to optimize your sleep?

How to Use Data to Improve Sleep

Though the data collected by wearables or other sleep trackers may be imperfect, it can still be useful. It may be important to take a bird’s eye view of the information that is collected. Consider these simple recommendations:

1. Trust your own experiences.

Before buying into the data collected by an imprecise, and possibly wholly inaccurate device, reflect on your own sense of how you are sleeping. Do you recall waking 30 times in the night? Do you remember dreaming, even though the device reported no dream sleep? Are you having difficulty explaining the sleep pattern it provides? If you feel like you are sleeping well, consider simply ignoring the sleep data your device may provide.

2. Use the information to reinforce good sleep habits.

It is helpful to keep a regular sleep-wake schedule. Get up at the same time every day, including weekends. Try to get 15 to 30 minutes of sunlight upon awakening. Go to bed at about the same time every day. Go to bed when you are feeling sleepy. Try to get at least 7 to 9 hours of sleep nightly, meeting your own sleep needs. Avoid naps when possible. If the sleep tracker helps to reinforce a regular schedule, it may be useful.

3. Don’t sweat the details.

There is evidence that data collected by sleep trackers can stress people out. It can add to anxiety and make insomnia worse. People become obsessed with the details, trying to explain every little blip in the data. If you find this is leading to obsessive behaviors for you, this could be a problem. Let it go. It may not be accurate anyway.

4. Corroborate the data with witness testimony.

There may be some inexplicable findings from your sleep tracker data. Perhaps some unremembered steps accumulated in the night. There may be frequent awakenings or restless sleep. The device may even report loud snoring. Try to verify these reports by asking a witness: consider questioning a bed partner. Learn if you sleepwalk, restlessly toss in the night, or rattle the windows with snoring. If there is a discrepancy, consider gathering more information before jumping to any conclusions.

5. If you are not sleeping well, get help.

Many people use sleep trackers because they are not sleeping well. They are hopeful that they may learn a little bit about why they are having difficulty sleeping. If the insomnia persists, this search can become desperate. Although some insight may be gleaned, more evaluation may be necessary. If you have poor sleep, especially if you have trouble sleeping through the night with frequent awakenings or experience daytime sleepiness, get evaluated by a board-certified sleep physician to sort out what might be contributing to your troubles.

Conclusion

It is fun to learn about ourselves. Sleep can be mysterious. Most of the night goes unremembered. It is natural to want to lift the curtain and glimpse a little about what occurs once our eyes close and we fall asleep. Be careful about positing too much faith into the accuracy of sleep trackers. The technology may improve with time, but these devices may be more novelties than serious scientific analyses. If you are struggling to sleep, get help from an expert.

Explore Causes of Restless Legs Syndrome

By Brandon Peters, MD

Although many people with restless legs syndrome (RLS) may never be able to identify a cause to their disorder, often it results from other secondary causes. This thus results in two categories of the condition, the former being primary RLS (of unknown cause) and the latter deemed secondary RLS. There are many conditions that may independently lead to symptoms of RLS and these are described here.

1. Iron Deficiency

The relationship between iron deficiency and RLS symptoms has been extensively studied. In several research studies, low iron levels have been found in the blood and spinal fluid of individuals suffering from RLS. The lower the iron levels, the worse the symptoms. Magnetic resonance imaging (MRI) has shown that the iron content in an area of the brain called the substantia nigra is lower in those with RLS compared to normal individuals, which may contribute to the disorder. In addition, pathological studies have confirmed this change within the brain.

It is therefore recommended that you have your serum ferritin level (a marker of iron stores) checked if you have symptoms of RLS. If the ferritin level is low, generally at a value <75, a trial of oral iron replacement should be undertaken. Even if the levels are normal, some individuals respond to iron replacement.

2. End-stage Kidney Disease

RLS is very common among individuals suffering from end-stage kidney disease, especially those who are dependent upon dialysis. The incidence has been reported to range from 6 to 60 percent. It is unclear what may be contributing to RLS in this group. Anemia, iron deficiency, or even low parathyroid hormone levels may have a role based on various studies. In some cases, treating anemia with erythropoietin therapy or iron replacement has been effective.

3. Diabetes

In people with Type 2 or adult-onset diabetes, RLS may develop. If diabetes is left uncontrolled, nerve damage can result. This is thought to occur because of high levels of glucose within the blood. This can lead to damage of small blood vessels that supply the nerves called vaso nervorum. When these become clogged, the nerve itself will become damaged. Often this leads to a peripheral neuropathy, which consists of pain and a pins-and-needles sensation in the feet. This may progress up the legs and even involve the hands. Associated with these sensory changes, some people will also have symptoms of RLS. Therefore, it is thought that diabetes may be an independent risk factor for developing RLS. In people who have undergone pancreas and kidney transplants, their symptoms of RLS have improved.

4. Multiple Sclerosis

There is a growing body of evidence that multiple sclerosis seems to be associated with an increased risk of having RLS. Some of the studies are conflicting, however. In one of the larger studies that included 1500 subjects, the prevalence of RLS was 19 percent in people with MS compared to only 4 percent of those people without it.

5. Parkinson’s Disease

It is thought that RLS and Parkinson’s disease may be caused by a similar problem, namely disruptions in the neurotransmitter called dopamine. This is not fully understood, however. Regardless, RLS may be present in individuals who have Parkinson’s disease, with a prevalence ranging from 0 to 20.8 percent, based on the study. Parkinson’s disease often involves a sense of restlessness (called akathisia) that may also occur in RLS, which may make it difficult to discriminate between the disorders. When both conditions are present, RLS usually occurs after Parkinson’s disease has become apparent.

6. Pregnancy

Not all conditions that may lead to RLS are disorders. In fact, the state of being pregnant seems to increase not only the incidence but also the degree of RLS symptoms. In a study of 626 pregnant women, only 10 percent had symptoms of RLS prior to becoming pregnant but this increased to 27 percent during pregnancy. It seemed to worsen in the third trimester. The good news is that the symptoms rapidly improved after delivery. It is not clear what causes the increased frequency of RLS during pregnancy. It may be due to iron or folate deficiency or even because of hormonal changes associated with being pregnant.

7. Rheumatic Disease

There are many conditions such as rheumatoid arthritis, Sjogren’s syndrome, and fibromyalgia that may have an association with symptoms of RLS. This relationship is unclear. In one study, 25 percent of individuals with rheumatoid arthritis had RLS symptoms compared to only 4 percent of osteoarthritis. In another study, 42 of 135 patients with fibromyalgia had RLS. The exact reason for this association is not fully understood.

8. Varicose Veins

In some instances, poor blood flow in the legs has been associated with RLS. In particular, weak veins that distend and become uncomfortable have been blamed. These so-called varicose veins are often engorged and blue in color and may be a sign of venous insufficiency. In a study of 1397 patients, 312 people complained of symptoms of RLS.

Treatment of varicose veins has proven to be effective in alleviating some of the symptoms of RLS. Sclerotherapy led to initial improvement in 98 percent of people, with relief maintained at two years in 72 percent. Medication treatment, including hyrdoxyethylrutoside, has also been shown to be modestly effective.

9. Other Conditions

Beyond the conditions described above, there are many other disorders that seem to be associated with RLS symptoms. These include:

• Obesity

• Obstructive sleep apnea

• Hypothyroidism

• High blood pressure

• Heart disease

• Peripheral neuropathies

• Vitamin deficiencies

• Excessive caffeine intake

• Low blood sugar

• Lumbosacral radiculopathy

• Spinal stenosis

• Use of mianserin (an antidepressant medication)

Sources:

Earley, CJ et al. “Abnormalities in CSF concentrations of ferritin and transferrin in restless legs syndrome.” Neurology 2000; 54:1698.

Allen, RP et al. “MRI measurement of brain iron in patients with restless legs syndrome.” Neurology 2001; 56:263.

Connor, JR et al. “Neuropathological examination suggests impaired brain iron acquisition in restless legs syndrome.” Neurology 2003; 61:304.

Kavanagh, D et al. “Restless legs syndrome in patients on dialysis.” Am J Kidney Dis 2004; 43:763.

Merlino, G et al. “Association of restless legs syndrome and quality of sleep in type 2 diabetes: a case-control study.” Sleep 2007; 30:866.

Manconi, M et al. “Multicenter case-control study on restless legs syndrome in multiple sclerosis: the REMS study.” Sleep 2008; 31:944.

Lee, JE et al. “Factors contributing to the development of restless legs syndrome in patients with Parkinson disease.” Mov Disord 2009; 24:579.

Manconi, M et al. “Restless legs syndrome and pregnancy.” Neurology 2004; 63:1065.

American Academy of Sleep Medicine. International Classification of Sleep Disorders. 3rd Edition Text Revision. 2024.

Walters, A. “Restless legs syndrome and periodic limb movements of sleep.” Continuum. Neurol 2007;13(3):115-138.

How Does Screen Light Affect Sleep?

By Brandon Peters, MD

In a world increasingly dependent on technology, bright screens are more commonly part of our everyday life. These screens range broadly in size and purpose: televisions, computers, tablets, smartphones, e-books, and even wearable tech. How does this artificial light, especially when viewed at night, potentially impact our sleep? Learn how light at night affects our body’s circadian rhythm and whether it might contribute to insomnia and difficulty awakening. In addition, consider ways to reduce light exposure and counteract its effects.

Before Thomas Edison and His Light Bulb

It is hard to imagine a time before artificial light existed. It is such an integral part of our lives that we consider ourselves deeply inconvenienced when we lose power in a storm. Think back to what life was like before modern technology like computers and televisions, before light bulbs, and even before electricity.

Primitive societies and people were highly dependent on the natural availability of light. The sun ruled life. It is no surprise that it was worshiped in ancient Egypt. When artificial light became possible, things dramatically changed.

The Influence of Light on the Body’s Functions

All life on Earth has developed patterns of activity dependent on the timing of day and night. When isolated from the natural environment, innate circadian patterns will be revealed. As an example, most humans have an internal clock that runs just over 24 hours in length. However, light profoundly affects the timing of sleep and wakefulness, metabolism, and hormone release.

Morning sunlight has a key influence on life’s functions. It promotes wakefulness and ends sleep. It can help shift the desire for sleep slightly earlier. In the winter, when sunlight comes later, we may want to sleep in or suffer from symptoms called winter depression.

Due to the length of our internal clock, our bodies have a natural tendency towards delay in the timing of our sleep. This means that we always find it easier to go to bed and wake later. Have you ever noticed how easy it is to stay up another 15 minutes but how difficult it is to wake just 15 minutes earlier? Morning sunlight can profoundly reset this internal clock.

How Artificial Light at Night Impacts Sleep

Unfortunately, artificial light at night can negatively affect the timing of our sleep. Light shifts sleep timing, and light at night can shift our desire for sleep later. This can result in difficult falling asleep, as occurs with insomnia. Night owls, or those with delayed sleep phase syndrome, may be especially susceptible.

Not everyone is sensitive to these effects. If you are especially sleepy, perhaps due to inadequate total sleep time or poor sleep quality, you are unlikely to be impacted.

There are several important factors to consider:

The Source of Light

Artificial light can come from light bulbs and many other sources, including televisions, computers, tablets, smartphones, e-books, and even wearable tech. Each of these can generate a different intensity of light. Near screens may have more impact that those across a room.

The Amount of Light

Most overhead lights generate a light intensity that varies from about 500 to several thousand lux. For comparison, full sunlight at midday may be 100,000 lux in intensity. Commercially available lightboxes often generate about 10,000 lux. The screen of your smartphone may create hundreds of lux of light, depending on the settings you use. Even smaller amounts of light, such as from a tablet screen, may have an impact in some people.

The Color of Light

Much is made of the fact that blue light is responsible for shifting circadian rhythms. Full spectrum light – what you might consider as “white light” or “natural light” – contains the blue wavelengths. Blue-blocker sunglasses (with an amber or orange lens) and screen filters are sold to block this light wavelength.

The Timing of Light

One of the most important variables is when you are exposed to light, including from artificial sources. There is evidence that light at night could shift your desire for sleep by about 1 hour. This delays your ability to fall asleep and may impact your desire to wake in the morning.

Therefore, it is very important to turn down the lights at night, especially preceding your bedtime. Some people may need to avoid excessive artificial light exposure for the 1-2 hours before going to bed. This means turning off the phone, powering down the computer, and avoiding light from tablets, e-books, and other sources.

Instead, try to stick to low-tech options: listen to some music, read a book printed on old-fashioned paper, or page through a magazine. By reducing and eliminating your exposure to light at night, you may find that you are able to sleep better. If you continue to struggle, speak with a sleep doctor about additional treatment options.

What Is the Best Temperature for Sleep?

By Brandon Peters, MD

It can be a common battleground for couples who sleep together: What is the best temperature for sleep? Whether you are fighting over a thermostat setting, disagree on the best bedding or sleep attire, or are tugging or throwing covers from one side of the bed to the other, the effects of the bedroom temperature may be important. It may even cause insomnia. Learn the optimal room temperature for sleep, what to do if it is too warm or too cold at night, how to sleep better if the temperature is uncomfortable in the summer or winter, and what medical conditions may make it hard to regulate body temperature at night.

The Effects of the Bedroom Environment on Sleep

First, consider what makes for an ideal bedroom environment. Beyond reserving it as a space for sleep and removing electronics, including bright screens, it is also important to consider the roles of noise, light and temperature. As a general, the bedroom should be quiet, dark, and a cool but comfortable temperature. Why might this be?

Consider how you would be sleeping if you did not have a modern home. Imagine as it was 40,000 years ago, living as a Neanderthal. Normal bodily processes, including sleep and temperature regulation, would be closely tied to the natural environment. When it becomes dark and starts to cool off, your body temperature also drops and you would get sleepy and lie down for the night. These same patterns persist in the present day, driven by genetic and environmental factors.

The body temperature reaches its lowest point about 2 hours before your normal wake time. This means if you usually wake up at 6 a.m., your minimum core body temperature will occur at 4 a.m. If you have ever stayed up through the night, you may have noticed how cold you feel at this time. Most of the time we are asleep, however. Towards morning, as the sun approaches the eastern horizon, our body temperature starts to increase, following a consistent circadian (“near day”) pattern.

The pairing of our body temperature to the temperature of the environment helps to minimize heat loss overnight. It may promote normal features of sleep, including the patterns of deep and REM sleep. But what is the best temperature for sleep?

What is the Ideal Bedroom Temperature?

Sleep experts at the National Sleep Foundation recommend that there is an ideal bedroom temperature range to promote healthy sleep. These ranges may vary somewhat based on age. Consider these recommendations:

• Babies and toddlers: 65 to 70 degrees Fahrenheit (18 to 21 degrees Celsius)

• Children and adults: 60 to 67 degrees Fahrenheit (15 to 19 degrees Celsius)

It may be best to use a smart thermostat to regulate the temperature of your home, turning down the temperature setting overnight. A degree variation from these recommendations, higher or lower, likely has little effect. Though these suggestions may be comfortable for most people, respect your body. If you feel too cool, or too warm, you may have to make some adjustments.

What If It Is Too Cold?

If you sleep in an environment that is too cold at night, your body will have to work to maintain your core body temperature at the desired level. This may provoke shivering, as the muscles of the body contract to produce warming energy. Feeling cold at night may also provoke awakenings. This may be helpful to make changes in the environment, such as pulling up covers or snuggling close to a bed partner. Unfortunately, it may also contribute to poor sleep quality and insomnia.

In extreme scenarios, such as sleeping unprotected in the woods with inadequate clothing, may provoke a serious decrease in the body temperature that can lead to hypothermia and even death due to exposure.

What If It Is Too Warm?

Almost everyone has experienced a night when their bedroom was too warm, making it hard to fall asleep. This may occur in the summer on especially hot days. What occurs when the bedroom is too warm at night?

Not surprisingly, the most common side effect of feeling too warm at night is sweating. The body regulates its temperature by increasing blood flow to the periphery (including to the hands and feet). It also promotes evaporative cooling by causing sweating. Just like during wakefulness, sweating may start in the hair of the head, armpits, and groin. If additional cooling is needed, the torso (chest, abdomen, or back) or extremities (arms and legs) may become slick with sweat.

Beyond feeling sweaty, there may be restless sleep with frequent awakenings and position changes contributing to insomnia. Attempts may be made to flip a pillow over to its cool side, to throw off covers, or to move away from a bed partner. It may be necessary to remove clothing, such as shedding warm pajamas or other sleep attire. It may help to open a window overnight, so the natural cooling of the environment can occur in the bedroom as well. In some cases, major adjustments may be necessary, including changes in the mattress or pillow (such as avoiding memory foam) to improve temperature regulation during sleep.

If the body temperature increases to a dangerous level, the effects of the resulting fever may cause serious consequences, including loss of consciousness, seizures, coma, and even death.

What About Humidity?

Beyond temperature, it is also important to consider the effects of humidity on sleep. When air is cold, or warm, there are changes in the amount of moisture that the air contains. In the winter, colder air may be more dry and this may affect the ability to breathe optimally during sleep. This may lead to nasal dryness or congestion, increasing snoring or sleep apnea, or even may make it more likely to develop upper respiratory illnesses like colds or influenza. Humidifier use, especially in a dry climate, may make it more comfortable to breathe at night and this may improve sleep. 

How to Sleep Better During Cold Weather 

What should you do if you are having difficulty sleeping due to a bedroom that is too cool? This may be more likely during cold weather during the winter months. It may also occur if you share a bedroom with someone who prefers a cooler temperature. Consider these options:

• Wear warmer pajamas (think flannel)

• Use extra blankets or an electric heated blanket

• Put heavier bedding on the bed (such as a heavy comforter or duvet)

• Turn up the thermostat

• Consider a space heater (kept away from flammable materials and with a safety timer feature to automatically turn off)

• Cuddle with a bed partner or pet

• Wear warm socks to bed

• Drink a warm beverage before bedtime (but avoid caffeine)

• Take a hot shower or bath prior to coming to bed

• In some cases, you may need to sleep in a different bedroom from someone who has a starkly different temperature preference at night.

How to Sleep Better During Warm Weather 

What if it is just too hot at night? Fortunately, there may be some helpful interventions to cool off at night when the weather gets too warm. Review these suggestions:

• Choose light, breathable sleep attire (such as cotton) or sleep naked

• Remove heavy blankets and bedding and consider using just a sheet

• Set up a circulating fan near the bed

• Use the air conditioning overnight

• Take a cool shower or bath prior to bedtime

• Leave the windows open at night

• Avoid artificial memory foam mattresses or pillows

• Consider the use of cooling devices (including pillows, sheets, pads, or even headgear)

If the unpleasant weather is due to a summer heat wave, hopefully it breaks quickly and your sleep will promptly return to normal as it does.

Is Poor Temperature Regulation a Medical Condition?

It is normal to question whether a difficulty regulating the body temperature at night is due to a medical condition. In some cases, such as an acute illness associated with a fever, it clearly is. There may be other chronic medical conditions that affect temperatures at night as well.

The most common conditions that impact the body temperature overnight are related to hormones. Thyroid problems often cause sweats or chills, correlating with hyperthyroidism or hypothyroidism, respectively. In addition, night sweats may be linked to the hormonal changes of menopause.

Sweating may occur due to the side effects of some medications. Sleep disorders such as sleep apnea can lead to frequent sweats due to the associated bursts of cortisol (stress hormone). Obesity, anxiety, and even hypoglycemia may cause sweats at night.

There are rare conditions that can cause elevated temperatures at night, including infectious diseases like tuberculosis and even some cancers. If the temperature regulation problems persist without explanation, especially in the context of other symptoms, it may be worth getting checked out. 

Conclusion

If you have difficulty sleeping comfortably at night, review whether you can make some changes to help yourself to sleep better. If you struggle with chronic insomnia, consider cognitive behavioral therapy for insomnia (CBTI). Fortunately, speaking with a board-certified sleep physician can often provide you the answers you need to sleep normally throughout the year, tolerating the normal variation of nighttime temperatures.

Sources:

Troynikov O, et al. “Sleep environments and sleep physiology: A review.” J Therm Bio. 2018 Dec;78:192-203. doi: 10.1016/j.jtherbio.2018.09.012. Epub 2018 Oct 5.

Szymusiak R. “Body temperature and sleep.” Handb Clin Neurol. 2018;156:341-351. doi: 10.1016/B978-0-444-63912-7.00020-5. 

Roth T, et al. “A novel forehead temperature-regulating device for insomnia: a randomized clinical trial.” Sleep. 2018 May 1:41(5). doi: 10.1093/sleep/zsy045.

Lappharat S, et al. “Effects of Bedroom Environmental Conditions on the Severity of Obstructive Sleep Apnea.” J Clin Sleep Med. 2018 Apr 15;14(4):565-573. doi: 10.5664/jcsm.7046.

Kryger MH, et al. Principles and Practice of Sleep Medicine. ExpertConsult, 6th edition, 2017.

How to Take Melatonin

By Brandon Peters, MD

Melatonin is a naturally occurring hormone that is often taken in a pill form as an over-the-counter supplement to aid sleep. It is most helpful in circadian rhythm sleep disorders, but it is frequently taken to alleviate difficulty falling or staying asleep (characteristic symptoms of insomnia). If you are interested in using melatonin to help you to sleep, you may wonder how to take melatonin, as well as the appropriate dose and timing.

What Dose of Melatonin Should I Take?

Melatonin is believed to be relatively safe and it is therefore available over-the-counter at many pharmacies and health supplement stores. It may be compounded in multiple different ways, and it is sometimes even added to other products meant to aid sleep. Pure melatonin is most often sold as a pill or capsule, but you can also buy it in a liquid or even spray form.

The advertised strength of the melatonin dose may range from 1 mg up to 10 mg or more. It is important to remember that melatonin is not regulated by the Food and Drug Administration (FDA). As such, production and quality standards are not enforced, so the dose may actual vary from the listed strength.

Research suggests that even quite low doses of melatonin may be effective, especially in circadian rhythm disorders. The relationship between the dose and the perceived effect -- a so-called dose-response relationship – does not appear to exist for melatonin. Therefore, it is difficult to determine the optimal dose for an individual. Given these limitations, it is probably best if you take the lowest possible effective dose. (This would mean taking 1 mg or 2 mg to aid sleep.) If you take too much, you may actually flood your system and the benefits will be counteracted. The timing of the dose is very important and high blood levels at the wrong times may be a problem.

When Should I Take Melatonin?

The role of melatonin in regulating our biological clock, or circadian rhythm, appears to be critical. Therefore, the timing of when you actually take it is just as important. It is normally produced in part of the brain called the pineal gland and is released during the period of darkness from sundown to sunrise. When taken as an oral supplement, it reaches a maximum concentration in your blood after 30 minutes. However, the timing of administration may not be quite so simple.

Most people should take melatonin in the evening before going to bed, but -- curiously -- there are others who should actually take it in the morning. How do you know when you should take it? If you have trouble falling asleep (especially if you want to stay asleep in the morning), you should take it at night. However, if you have no trouble falling asleep but you awaken too early in the morning, you should actually take it in the morning. (As an aside, you should also ensure that you have ample light exposure at the opposite time from when you take your melatonin.)

Now that you have figured out whether to take it in the morning or at night, how close should you take it to your desired bedtime (or after awakening)? If you decide to take it at night, you should take it 3 hours before your desired bedtime. Conversely, if you are falling asleep and awakening too early, you may take it 3 hours after waking.

Is It Safe to Take Melatonin Every Night?

As described above, melatonin is extremely safe. It is a hormone that your body makes naturally. Its use in a supplement form is also believed to be quite safe. It is not habit forming and you will not become “addicted” or dependent upon it. Therefore, if you find it to be helpful in improving your sleep, you may use it on a nightly basis without fear of adverse consequences.

Source:

Kryger, MH et al. "Principles and Practice of Sleep Medicine." Elsevier, 5th edition, pp. 916-920.

Optimizing the Bedroom Environment for Sleep

By Brandon Peters, MD

It may seem like a rather inconsequential thing, but you shouldn’t underestimate the importance of the bedroom environment to sleep. It may be the one thing that helps you quickly transition to rest—or the thing that keeps you tossing and turning all night in fits of insomnia.

What is the Sleep Environment?

The sleep environment is simply the space in which you attempt to sleep. It may vary as our lifestyle dictates. For example, a business trip, a prolonged flight, or a camping expedition may result in sleep environments as variable as a hotel, an airplane, or a tent. Ideally the space in which we attempt to sleep would be conducive to our efforts.

Not everyone will agree on what makes for the best features of a chosen sleep environment. This may lead to relationship problems between bed partners requiring that we attempt to find common ground. There are a handful of common variables, however, that should be acknowledged:

1. Noise

In general, it is easiest to sleep in a quiet place. Whether it is a vestige of surviving in the wilderness or for some other reason, we tend to respond to external stimuli while asleep. In other words, if we hear a noise, we will wake up. This is advantageous if a lion is trying to eat us while we sleep in a cave, but when the neighbor is blasting the radio too loud it is less desirous.

When we hear noise we may not come fully to consciousness, but we certainly will leave deeper stages of sleep. If we are trying to sleep in a noisy environment, our ability to enjoy restful deep sleep will be compromised. It is therefore best to try to keep things as quiet as possible.

2. Temperature

Most people prefer to sleep in a slightly cool environment. You may bury yourself in thick blankets, but no matter how you choose to sleep, you no doubt want to be at the right temperature. Most people should target a bedroom temperature between 60 and 67 degrees. If you wake up shivering or drenched in sweat, the temperature of your sleep environment is a problem. Why is it a problem? It woke you up! When determining the best options for your sleep environment always remember that your goal is to sleep soundly.

3. Lighting

The amount of light can impact how well you sleep. In general, it is best to sleep in darkness. You may prefer to have a nightlight (especially for safety reasons if you get up during the night). Our body’s natural circadian rhythm tends to want to follow the natural dark-light cycle. Therefore, even if you are working nights, you should probably try to keep it dark when you are trying to sleep.

4. Bedding/Mattress

There are a variety of options in how people choose to sleep and there is no one right way. Variations may relate to personal preference, cultural practices, financial opportunities, and many other factors. Some things to consider may be the use of a mattress and its character (such as size and firmness). You may prefer only a sheet or mounds of blankets or a thick comforter.

5. Preserving the Sleep Space

The bedroom can sometimes become a multipurpose room, especially if you have space constraints (such as those in college dorms). You may choose to have a television in your bedroom or even sleep with your favorite pet at your side.

The bedroom space should be a relaxing place and not a source of stress or stimulation. As part of the general guidelines for good sleep, bedrooms are for sleep and sex, not for other activities. You should not be doing work there. Various electronics (televisions, gaming systems, computers, telephones, and other gadgets) should be removed from your sleep environment. Not only will they prevent you from falling asleep, they may become disruptive at inopportune times and wake you back up.

By carefully considering the variables in your sleep environment and preserving the space to foster a good night’s sleep, you will be able to rest better and wake up ready to have a successful and productive day.

What Is Jet Lag?

By Brandon Peters, MD

Jet lag is a circadian disorder that transiently occurs after rapid travel across multiple time zones. It may be associated with other physical symptoms, including disturbed sleep. Learn about this common condition, its symptoms, and potential treatments.

If you have ever flown across a few time zones, you are undoubtedly familiar with the struggles of adjusting your sleep to the new hours. Why is jet lag, as it is called, so hard to tolerate and is there anything to be done?

First, it should be recognized that your body wishes to keep a regular sleep schedule. Certainly we are creatures of habit, and our bodies like when we go to bed and get up at the same time every day. Our biological clock, which is controlled by part of the brain called the suprachiasmatic nucleus, helps us to keep a regular schedule by releasing hormones on a regular pattern. This pattern is called a circadian—or “near day”—rhythm. Our sleep follows this same regular pattern.

When we disrupt the regularity of these cycles, our body treats us unkindly by making us sleepy or alert when we don’t wish to be. For example, if you were to go to bed three hours early tonight, you would have great difficulty falling asleep. However, if you fly from California to New York and crawl into bed at your normal bedtime, you are effectively attempting the same thing.

Causes

Rapid travel across multiple time zones leaves the circadian rhythms out of sync with the destination’s light-dark cycles. These rhythms affect sleep and wakefulness as well as metabolism, body temperature, and hormone release. It can take time for the internal circadian rhythm to be re-synchronized to external time cues. Jet lag is sometimes called desynchronosis, referring to the misaligned sense of time.

As a general rule, it is possible to adapt at an average rate of 1 hour per day. For someone who lives in California to fly to New York and cross three time zones, it would usually take 3 days to adjust to the new time zone. It is generally easier to travel westward and harder to travel eastward for most people.

Social jet lag may cause less intense symptoms and occurs in people who delay their bedtime and wake time by 1 to 2 hours on weekends and then have to correct as the work week resumes on Monday. This shift in the circadian timing may affect the start of the work week for several days.

Significance

In the new location, circadian signals may conflict with environmental and social cues in the context of jet lag. This may lead to a constellation of symptoms, including:

• Excessive daytime sleepiness

• Fatigue

• Insomnia

• Irritability

• Poor concentration

• Digestive problems (dyspepsia)

• Malaise (feeling unwell)

These symptoms may be disruptive and may be exacerbated by sleep deprivation, dehydration, sleep environment changes, and stress associated with travel.

Testing

The presence of the typical symptoms in the context of jet travel confirms the diagnosis without the need for further testing. In research, it is possible to measure an individual’s circadian pattern with tests that detect melatonin levels, often sampled from repeated saliva measurements. There are new blood tests also coming into clinical use that may identify the circadian rhythm.

Associated Conditions

Jet lag is most commonly associated with insomnia, defined as difficulty falling asleep or returning to sleep after waking. If insomnia occurs for less than 3 months, it is termed acute insomnia. As most people would be taking trips of a shorter duration than this, it could be grouped with other briefer disturbances of sleep. In some cases, jet lag may trigger a disruption that may evolve into a chronic form of insomnia.

Treatment

How can we counter our circadian rhythm when we travel? There are several techniques to reduce the effects of jet lag.

One solution would be to keep the same hours as our original time zone, going to bed and getting up based on the times at home.  his may not be the best way to enjoy our travels, especially if we fly great distances. An alternative would be to slowly adapt to the new time zone prior to leaving.

It may be possible to prepare the body gradually prior to departure by slowing adjusting bedtime and wake time to match the destination’s time. This can be done by adjusting our sleep by an hour for a week at a time. If we are crossing two time zones, the change can occur over two weeks. If traveling west, we would go to bed and get up an hour later for one full week. During the second week we would repeat the same, going to bed and getting up another hour later. If traveling east, we would go to bed and get up an hour earlier each week. If we can slowly adapt to the change, we will tolerate it better.  Unfortunately, unless the trip is quite lengthy, we wouldn’t be able to adjust the other way for our return home.This adjustment may be enhanced with properly time light exposure.

Light is one of the primary synchronizers of the circadian rhythm in sighted individuals. It may advance the timing of sleep earlier if the light exposure occurs in the 2 hours prior to the normal wake time or immediately upon awakening. Sunlight is best, but the use of light boxes or light therapy boxes may also have a role.

Beyond light, it may be important to address the symptoms that occur. Caffeine or strategic napping may relieve sleepiness. Other stimulant medications could also have a role. It may also be helpful to use hypnotic medications to aid sleep, including over-the-counter melatonin or prescription pills, such as:

• Zolpidem (Ambien)

• Eszopiclone (Lunesta)

• Zaleplon (Sonata)

• Ramelteon (Rozerem)

These medications to aid both wakefulness and sleep may ease the transition to a new time zone.

Conclusion

If you have a big trip coming up, you might plan ahead in how you can adjust your circadian pattern of sleep and wakefulness with some of the interventions outlined. This may help to optimize your experience while traveling to avoid the symptoms of jet lag.

Sources: 

Drake CL and Wright KP. Shift Work, Shift-Work Disorder, and Jet Lag. Principles and Practice of Sleep Medicine, 6thed., Philadelphia, Elsevier, 2017. pp.714-725.

American Academy of Sleep Medicine. International Classification of Sleep Disorders, 3rd ed. Darien, IL: American Academy of Sleep Medicine, 2014.

Gooley JJ. Treatment of circadian rhythm sleep disorders with light. Annals of the Academy of Medicine, Singapore. 37(8):669-76, 2008 Aug.

Sack RL. The pathophysiology of jet lag. Travel Medicine & Infectious Disease. 2009 Mar;7(2):102-10.

Sack RL. Circadian rhythm sleep disorders: part I, basic principles, shift work and jet lag disorders. Sleep. 30(11):1460-83, 2007 Nov 1.

Srinivasan V, et al. Jet lag: therapeutic use of melatonin and possible application of melatonin analogs. Travel Medicine & Infectious Disease. 6(1-2):17-28, 2008 Jan-Mar.

What Factors Make Sleep Apnea Worse?

By Brandon Peters, MD

Though your anatomy may predispose you to having obstructive sleep apnea, there are other factors that might actually make the condition worse. Some of these potential contributors are within your control and others are not. What makes sleep apnea worse and what can you do about it?

Starts with Your Anatomy

The most important cause of sleep apnea is the structure of your airway’s anatomy. There are a number of components that have a role: nose, tonsils, palate, tongue, and jaw. These structures develop based on your genetics. Just like we share a familial resemblance with our parents and siblings, so too the internal structures are similarly arranged. Unfortunately, this foundation is largely out of your control, but there are other factors that might make sleep apnea worse. Some of these additional considerations include:

Sleep Position

Some people’s sleep apnea is significantly worsened by sleep position. A sleep study might show that sleeping on your back, in the supine position, leads to increased breathing disruption. This occurs because the soft tissues of the airway, including the soft palate and tongue, can fall backwards and block the passage of air. Gravity contributes and lying on your back will make this occurrence more likely. In some individuals, the use of positional therapy to stay sleeping on your sides can be very helpful.

REM Sleep

It is natural to transition through various sleep stages throughout the night. The majority of sleep consists of non-REM sleep. However, about every 90 minutes REM sleep occurs. Rapid eye movements occur along with paralysis of muscles. This state is characterized by intense, vivid dreaming, much like watching a movie. In order to prevent the acting out of these dreams, the body is actively paralyzed. The muscles of the airway are also paralyzed. This tube becomes floppy and collapsible. As a result, sleep apnea often worsens during REM sleep. This may cause an increased number of events or more severe drops in oxygen levels as measured by oximetry. As REM sleep is an integral part of quality sleep, this particular risk factor cannot be avoided.

Alcohol

Counter to the tradition of having a nightcap, it is clear that alcohol negatively affects sleep. Although it may make you feel sleepy, as it wears off it leads to sleep fragmentation and insomnia. In addition, as a muscle relaxant, it can make the upper airway more collapsible. This risk factor is within your control. It is best to avoid alcohol before bedtime. As a rule of thumb, allow one hour to elapse for each alcoholic beverage you consume before going to bed. This will help to minimize the effects of alcohol on your chance of experiencing sleep apnea.

Menopause

Okay, so this one obviously only applies to women. However, it is a significant risk factor to consider. Younger women are protected by the hormones progesterone and estrogen which maintain the patency of the airway. The incidence of sleep apnea among women before the onset of menopause is thus lower. When these hormones are lost, the incidence increases among women to equal that of men. Surgical menopause, a phrase used to describe the state after which hysterectomy and removal of the ovaries has occurred, conveys a similar risk of sleep apnea. Women who take hormone replacement therapy are found to have an intermediate risk of sleep apnea.

Prescription Medications

How might medications affect sleep apnea? In general, there are three classes of medications that are potentially problematic: benzodiazepines, opiates, and barbiturates. Benzodiazepines are often prescribed for anxiety, seizures, and were previously often used for insomnia. They also act as muscle relaxants and this can affect the airway and lead to sleep apnea. Opiates are narcotic medications that are used to control pain. They can contribute to central sleep apnea, characterized by shallow or irregular breathing. In addition, barbiturates are used for sedation and seizure control and these can likewise affect breathing. If you are concerned that your medications may be increasing your risk of sleep apnea, you should speak with your prescribing doctor.

Aging

Finally, aging itself may make your sleep apnea. Just as you lose muscle tone in your arms and legs, you similarly may lose muscle tone within your airway. This may compromise its ability to stay open. There isn’t much to be done about this particular risk factor. The good news is that the incidence of sleep apnea appears to level off at the age of 60. If you are going to develop sleep apnea, it seems, you will develop it by then.

Regardless of the issue that might be making your sleep apnea worse, there are still effective treatment options available including the use of an oral appliance or continuous positive airway pressure (CPAP). Discuss the risks you face with your sleep specialist and find the right solution for you.

Sources:

Kryger, MH et al. "Principles and Practice of Sleep Medicine." Elsevier. 5th edition. 2011.

The International Classification of Sleep Disorders. American Academy of Sleep Medicine. 2nd edition. 2005.

How Long Should You Wait Between Screen Light Exposure and Going to Bed?

By Brandon Peters, MD

There is some concern that light exposure at night may affect sleep. What is the evidence that artificial light from screens contributes to insomnia? How long should you wait between screen light exposure and going to bed? Explore this relationship and some of the science behind the rationale.

The Science of Sleep

When considering how optimal sleep occurs, it is important to understand the two primary contributors: homeostatic sleep drive and circadian rhythm. Sleep drive is the fact that the longer you stay awake, the sleepier you will become. This is due to a chemical that gradually builds in the brain with prolonged wakefulness. This chemical is called adenosine. High levels of adenosine contribute to the onset of sleep. Sleep, at least in part, is a process of clearing this chemical away until consciousness is restored. Interestingly, caffeine blocks this signal and alcohol enhances it.

The circadian rhythm is the complement to this system. It is predominately an alerting signal that strengthens during the daytime and is largely absent overnight. It becomes strongest in the late evening hours, when we would expect to feel fairly sleepy. There is a lull in the mid-afternoon, which can contribute to a desire to take a nap then.  The circadian rhythm is based in our genetics, persisting without external influences. It contributes to sleep-wake propensity, hormone release, and metabolism. These processes are linked to the day-night cycle of light and darkness via the eyes.

How Light Changes Sleep

A simple anatomy lesson reveals the importance of light exposure to sleep. The eyes perceive light via the retina and pass this information along the optic nerves, extensions of the brain itself. These optic nerves receive input from each eye and cross at a location called the optic chiasm. Just above this is an area of the brain called the hypothalamus, a functional area that is integral to the control of the processes described above.

Within the hypothalamus lies the suprachiasmatic nucleus. This is the control center of the body’s circadian rhythm. It is the central pacemaker, coordinating the activities of all the body’s organs, tissues, and cells. Therefore, light input can be directly linked to the influence of many of the body’s processes.

In particular, light exposure can suppress the desire for sleep. Morning sunlight exposure may help to wake us, initiating the circadian alerting signal. In the same way, artificial light at night may affect the timing of sleep. It may contribute to insomnia in susceptible individuals, especially among those with a tendency towards being a night owl (called delayed sleep phase syndrome).

Preserving Darkness in the Night

What impact did Thomas Edison have on sleep in inventing the light bulb? As society has evolved, the potential disturbances have only expanded. With electricity, our evenings are filled with activity: televisions, computers, tablets, e-books, and phones that flicker light into our eyes. Moreover, the activity itself may keep us awake, shorten our total sleep time, and interfere with a relaxing buffer zone before bedtime. There is some evidence that light at night may adversely affect sleep.

Research has demonstrated that in the spectrum that we perceive as light, the blue wavelength is the one that can change our circadian rhythms. Therefore, industries have developed to supply filters and glasses that block the blue light. It seems that even short bursts of light, especially when of higher intensity, can impact sleep’s timing.

The sun is much more powerful in intensity compared to light from bulbs or screens. Full sunlight may be 100,000 lux in intensity while overhead lights may be just 1,000 lux. Therefore, a blast of sunlight at night could profoundly impact sleep. For susceptible individuals, artificial light may also negatively impact sleep onset and contribute to insomnia.

As a result, it is recommended that people who have difficult falling asleep may benefit from reduced light exposure prior to bedtime. Preserve the last 1 hour, and perhaps longer in highly sensitive individuals, as an electronics-free zone. Power off your screens, especially those that are closer to your eyes. It is also advisable to keep your bedroom free of electronics to preserve sleep. This is especially important advice for teens and children.

Why might some people not be bothered by light at night? The complement system, characterized by sleep drive and building levels of adenosine, could counteract these effects. If you are sleepy enough, you may not be bothered by the light. If you struggle with persisting insomnia, consider speaking with a sleep specialist to help determine ways for you to improve your sleep.

How Long Should You Wait Between Exercising and Going to Bed?

By Brandon Peters, MD

If you exercise late and have trouble falling or staying asleep, symptoms that characterize insomnia, you might wonder: How long should I wait between exercising and going to bed? Learn how much time should elapse after your exercise before bedtime and what symptoms you might experience if you don’t wait long enough before going to sleep.

The Relationship Between Exercise and Sleep

There are some theoretical impacts of exercise on sleep that you might take into consideration. Vigorous, aerobic exercise may increase your body temperature. An elevated body temperature may make it harder to fall asleep, as most of us prefer to sleep in a slightly cool environment. Fortunately, your body temperature is well regulated by sweating and once you are no longer sweating, it is likely mostly normalized.

In addition, exercise can release hormones such as cortisol and adrenaline (also called epinephrine). These hormones may rev you up, making it slightly harder to fall asleep. The good news is that they are likely not too disruptive and may actually enhance your sleep. In fact, when you are more active during the day, most people report sleeping better at night.

How Long to Wait Between Exercise and Bedtime?

In the past, sleep experts recommended avoiding exercise for 4 hours before going to sleep. Recently, this recommendation has changed. For many people who work, no exercise in the 4 hours before bedtime led too often to simply no exercise. Given the health implications, this is no longer suggested.

Instead, it is recommended that you stay active and exercise every day. It is not necessary to avoid exercising before bedtime. If you find that you are having difficulty getting to sleep on the nights you exercise right before bedtime, you might consider changing the timing of your exercise or your activity. In general, low-impact stretching and walking are great ways to unwind and may be done in the last few hours of the night without negative impacts on sleep.

If you continue to have difficult falling or staying asleep, speak with a sleep specialist about ways to help you to sleep better.

How Long Should You Wait Between Drinking Alcohol and Going to Bed?

By Brandon Peters, MD

If you drink alcohol late and have trouble falling or staying asleep, symptoms that characterize insomnia, you might wonder: How long should I wait between my last alcoholic drink and going to bed? Whether it is beer, wine, or hard liquors, learn how much time should elapse after your last drink before bedtime and what symptoms you might experience if you don’t wait long enough before going to sleep.

The Relationship Between Alcohol and Sleep

Alcohol has a dual relationship with sleep: it can make us feel sleepy initially while intoxicated and it can disturb our sleep as it wears off. The former characteristic led to alcohol’s frequent use as a nightcap, meant to assist in the transition to sleep. However, alcohol is a muscle relaxant. This can contribute to relaxation of the airway and worsen snoring and obstructive sleep apnea. In addition, alcohol has a short half-life, meaning that it wears off quickly. As the blood alcohol levels drop, decreasing through metabolism by the liver, this can contribute to sleep fragmentation and awakenings.

How Long to Wait Between Your Last Drink and Bedtime?

It is recommended that alcohol not be consumed in the last 2 to 3 hours before bedtime.

This timing actually varies somewhat based on your own rate of alcohol metabolism, which depends on the function of your liver, your body weight, ethnicity, and sex. It also matters how many servings of alcohol have been consumed.

As a general rule of thumb, it takes 1 hour for one serving of alcohol to be metabolized. Therefore, if you have a couple of drinks, you will want the last to be at least several hours before bedtime to avoid impacting your sleep.

If despite changing when you consume alcohol you continue to have difficult falling or staying asleep, speak with a sleep specialist about ways to help you to sleep better.

How Long Should You Wait Between Drinking Caffeine and Going to Bed?

By Brandon Peters, MD

Caffeine can be one of the great joys of life. If you have difficulty falling asleep, as occurs with insomnia, caffeine in coffee, tea, or soda pop may be the bane of your existence. You may wonder: How long should I wait between my last caffeine and going to bed? Learn how much time should elapse and what symptoms you might experience if you don’t wait long enough before going to sleep.

The Relationship Between Caffeine and Sleep

Good sleep occurs when it is properly timed to take advantage of both the body’s circadian rhythm and sleep drive. For most people, this means spending a prolonged period awake during the day (typically lasting about 16 hours) and attempting to sleep at night. In particular, the sleep drive may be affected by caffeine use.

The sleep drive is understood as the desire for sleep. It builds gradually with wakefulness due to the accumulation in the brain of a chemical called adenosine. Adenosine is a byproduct of metabolism and the longer we stay awake, the more it accumulates and the sleepier we gradually become. Caffeine directly blocks adenosine. This in effect reduces sleepiness and may contribute to difficulty falling or staying asleep after it is consumed. If you are extra sleepy, due to higher adenosine levels from poor quality or inadequate sleep, it may have little to no effect.

How Long to Wait Between Your Last Caffeine and Bedtime?

The million-dollar question is: How long should you wait between your last coffee or soda pop and going to bed? This is likely highly variable and is dependent on your individual levels of adenosine and tendency towards insomnia. For most people, caffeine should be avoided for 4 to 6 hours before bedtime. If you are highly sensitive, you might consider cutting it out after noon (or perhaps entirely).

Since there is some variability in its impacts, you could start by reducing it late and gradually move the deadline earlier as needed. Remember that it can be found in coffee, soda pop, tea, energy drinks, and even chocolate.

Caffeine may affect your sleep, but this may not be the only contributing factor. If you continue to struggle with insomnia, speak with a sleep specialist about other ways to improve your sleep, including participating in a cognitive behavioral therapy for insomnia (CBTI) program.

How Long Should You Wait Between Eating and Going to Bed?

By Brandon Peters, MD

If you eat late and have trouble falling or staying asleep, symptoms that characterize insomnia, you might wonder: How long should I wait between eating and going to bed? Whether it’s a midnight snack or simply your late dinner, learn how much time should elapse before bedtime and what symptoms you might experience if you don’t wait long enough before going to sleep.

The Relationship Between Food and Sleep

There are some foods that contain substances that may enhance sleep. For example, turkey and pork chops contain high levels of tryptophan, a substance that is metabolized by our bodies into serotonin and melatonin, sleep-inducing agents. In addition, some foods like cherries contain small amounts of melatonin. Other foods can be comforting, like a warm glass of milk, and this may help us to relax and mentally prepare for sleep. Alcohol in a nightcap can make us feel sleepy initially, but it wears off quickly and can actually fragment and disrupt sleep.

There is also some evidence that the timing of food can affect our sleep. It may prompt the release of insulin, which may have a role in shifting our circadian rhythm.

When Eating Undermines Sleep

Eating too close to bedtime can actually harm your sleep. This may be especially true if you eat too much or eat certain foods that induce heartburn. Lying down may cause reflux symptoms that cause burning chest discomfort and a bitter taste in your mouth. Spicy and acidic foods like citrus and tomatoes may be especially bothersome.

In addition, caffeine in coffee, tea, soda pop, energy drinks, and chocolate should be avoided. It blocks adenosine, a chemical that naturally makes us feel sleepy, and when consumed too close to bedtime may contribute to insomnia. It can also increase the need to urinate, which can lead to disruptive nocturia.

How Long to Wait Between Meals and Bedtime?

In general, it is recommended that you wait for 2 to 3 hours between your last meal and bedtime. This allows digestion to occur and the contents of your stomach to move into your small intestine. This will reduce the likelihood of heartburn symptoms. It may also reduce the chance of having sleep disturbances contributing to insomnia.

If after adjusting your meal times you continue to have difficult falling or staying asleep, speak with a sleep specialist about ways to help you to sleep better.

What Is Restless Legs Syndrome (RLS)?

By Brandon Peters, MD

Restless legs syndrome (RLS) is one of those conditions that sounds a little too strange to be true, but if you have ever laid down to fall asleep and felt an uncomfortable sensation of bugs crawling under your skin, you may be all too familiar with what RLS is. This condition may leave you kicking your legs as you fall asleep, but a better understanding of the disorder and its causes may lead to the treatment and rest that you need.

What is RLS?

RLS is a movement disorder that is characterized by unpleasant feelings in the legs associated with a need to move. The sensations (called paresthesias) may include aches, pulling, itching, or even the feeling of bugs crawling under the skin. The symptoms typically come on during periods of rest, especially at night, and are relieved by movement. They may make it hard to fall or stay asleep, resulting in insomnia.

There are four features that are used to diagnose RLS and these include:

1. An urge to move the legs, usually accompanied or caused by uncomfortable and unpleasant sensations in the legs.

2. The urge to move or unpleasant sensations begin or worsen during periods of rest or inactivity such as lying or sitting.

3. The sensations are relieved by movement, such as walking or stretching, as long as the activity continues.

4. The sensations are worse during the evening or night.

Symptoms typically come on within 15 to 30 minutes of resting. In very severe cases, the problems may occur with any seated activity during the day, such as sitting in meetings or in a movie theater. This may lead to fidgeting, constant movement, or the need to kick or massage the legs to relieve the symptoms. Some people are so bothered by the symptoms at night that they will get out of bed.

Individuals with RLS may experience periodic limb movements of sleep (PLMS), which consist of sudden jerking leg movements involuntarily during sleep.

How Common is RLS?

Mild symptoms associated with RLS occur in 5 to 15 percent of the population. It seems to increase as we get older and occurs more commonly in women.

There are two types of RLS. The first, called primary (or idiopathic) RLS, has no clear cause and tends to run in families. The other type, called secondary RLS, occurs as the result of separate conditions, including iron deficiency, diabetes, pregnancy, and more.

Diagnosis and Treatment of RLS

RLS is diagnosed using the four criteria described above. A sleep study called a polysomnogram is not necessary but it may be helpful if the condition is resistant to treatment. It is important to identify any contributing causes so that these can be addressed appropriately. The treatment of RLS may include iron replacement, a combination of medications (including those that enhance GABA or dopamine), exercises, and other therapies.

Sources:

Allen, RP et al. "Restless legs syndrome prevalence and impact: REST general population study." Arch Intern Med. 2003; 163:2323.

American Academy of Sleep Medicine. "International classification of sleep disorders: Diagnostic and coding manual." 3rd ed Text Revision. 2014.

Hogl, B et al. "Restless legs syndrome: a community-based study of prevalence, severity, and risk factors." Neurology. 2005; 64:1920.

How to Choose a Sleep Doctor

By Brandon Peters, MD

If you are having difficulties sleeping, you may need a referral to a sleep specialist, but how should you choose a sleep doctor? There are certain characteristics that you should consider when selecting a specialist so that you get the appropriate testing and help that you need.

Who is My Sleep Specialist?

There are many individuals who will be involved in your care if you seek treatment for a sleep disorder. You will likely start your evaluation with your primary health care provider. This may result in a referral to a sleep specialist, most often a physician but sometimes a midlevel provider such as a nurse practitioner or a physician’s assistant working under the supervision of a physician. There may be ancillary staff involved as well, including polysomnographic technologists who do the sleep studies.

Sleep Doctor Training

Physicians who are certified as sleep specialists have many years of education. To become a doctor they graduate from college with a four-year degree and attend four years of medical school. They then complete a medical residency and a fellowship in sleep medicine. Many specialists can pursue a sleep fellowship, including: pulmonologists, neurologists, psychiatrists, otolaryngologists (ear, nose and throat specialists) and even general practitioners in family medicine, pediatrics, or internal medicine. Some physicians may dabble in sleep medicine, even if they do not have formal board certification.

Finding a Specialist with Credentials

No matter the specialty training, it is advisable to seek out a physician who is certified with appropriate sleep medicine credentials from the American Board of Medical Specialties. This implies that your doctor’s education has been verified and that they have been able to pass a board examination that tests their knowledge of sleep medicine. If you are to undergo additional sleep testing, you may want to find a sleep center that with accreditation from the American Academy of Sleep Medicine.

Selecting an Appropriate Center

Finding a sleep specialist can be a little intimidating, but once you have found a reputable provider, you may want to evaluate whether he or she can meet your needs. You may rely on friends or family for recommendations. It is also important to consider how your condition may be evaluated. You will want to select a center that can provide a thorough and appropriate evaluation, including any necessary testing such as:

• Home sleep apnea testing

• Polysomnography

• Multiple sleep latency testing (MSLT)

As part of this consideration, you may need to take into account cost as well as your insurance coverage. The resources available to you are always expanding and with a little research you should be able to find a reputable sleep specialist to meet your needs.

When College Classes Start Late, Students Sleep and Drink More — and Get Worse Grades

At first glance, it sounds like the perfect solution to the student sleep crisis: start college classes later in the morning so students can get more rest. In theory, better-rested students should have sharper focus, stronger memory, and improved academic performance. And in some studies of high schoolers, that’s exactly what happens.

But research on college students paints a more complicated picture. In some cases, later class start times are associated not with better grades, but with worse grades — despite students sleeping longer. The difference lies in what students do with that extra flexibility and how college culture shapes their habits.

The Promise of Later Starts

Sleep scientists have long known that young adults, like teenagers, have a natural tendency toward later bedtimes and wake times. In high school, early start times often force students to wake before their biological clock is ready, leading to chronic sleep deprivation.

College seems like the ideal place to fix this: if students can choose later classes, they can sleep closer to their natural rhythms. On paper, this should mean:

• More total hours of sleep

• Better mood and alertness in class

• Stronger academic performance

And indeed, surveys confirm that students with later classes often report getting more sleep — sometimes an hour or more extra compared to their peers in early sections of the same course.

The Paradox: More Sleep, Lower Grades

However, large-scale studies have found that college students who take later classes often have lower GPAs than those with earlier schedules. A notable example is a University of Washington and University of California, Santa Barbara analysis, which showed that students with later first classes went to bed later, slept later, and engaged in more late-night activities — including drinking — that negatively affected academic outcomes.

Here’s the paradox: while these students may sleep longer, the timing of their sleep and their overall lifestyle may be less compatible with optimal learning.

Why Later Starts Can Backfire in College

1. Shifted Sleep Schedule

When the first class isn’t until 11:00 a.m. or later, many students push bedtime into the early morning hours. They still get their 8 hours — but much of that sleep occurs in a delayed cycle that can interfere with morning alertness and alignment with the day’s demands.

2. More Time for Late-Night Socializing

A later start means less pressure to wind down early. Parties, bar nights, and dorm hangouts can stretch into the small hours, with students feeling less need to cut themselves off because they “don’t have to be up early.” This can increase alcohol consumption and reduce sleep quality, even if total sleep time is higher.

3. Increased Alcohol Use

Multiple studies link later first classes with higher drinking rates among college students. The reasoning is simple: fewer morning obligations lower the perceived cost of staying out late and drinking. Unfortunately, alcohol disrupts the second half of the sleep cycle, leading to lighter, more fragmented rest that’s less restorative.

4. Lower Structure and Discipline

Early classes can serve as an anchor for the day — a reason to get up, get moving, and start on assignments earlier. Without that anchor, some students procrastinate on both waking up and starting work. Evenings fill with social activity, while afternoons may be spent catching up on sleep or idly passing time, leaving less total time for focused study.

5. Delayed Learning Window

Cognitive performance has daily rhythms, and for many people, attention and memory are strongest in the late morning. Students who push their academic work later in the day may be working during a lower-performance window, particularly if they’re also staying up past midnight.

The Role of Personal Responsibility

The impact of late starts varies by student. Self-disciplined students who use the extra rest to fuel productivity may see benefits. But for those still adjusting to the independence and distractions of college life, later classes can feed into a cycle of:

• Staying up late → Sleeping late → Less time for daytime study → Increased evening socializing → Staying up late again

This cycle isn’t inevitable, but it’s common — especially among younger undergraduates.

Alcohol, Sleep Quality, and Academic Performance

Even moderate alcohol use before bed can reduce the proportion of deep slow-wave sleep and REM sleep. For students in the “late start” group who drink more frequently, the benefits of longer sleep may be offset — or erased — by poorer sleep quality.

Poor-quality sleep leads to:

• Slower information processing

• Reduced working memory capacity

• Weaker problem-solving skills

• More difficulty concentrating in lectures

When those effects stack up over a semester, grades can take a noticeable hit.

What the Research Suggests

Several key findings emerge from the research on this topic:

• Later first classes = later bedtimes. Students rarely use the extra morning time to get more early sleep.

• Alcohol use increases. The absence of morning obligations removes a deterrent to late-night drinking.

• Grades can drop. The combination of later bedtimes, lower-quality sleep, and lifestyle changes appears to outweigh the benefits of extra rest for many students.

One study even found that for each hour a student’s first class started later, their GPA was slightly lower — largely explained by differences in sleep timing and alcohol use.

Navigating the Trade-Off

This doesn’t mean late classes are inherently bad — but it does mean students and educators should be aware of the trade-offs.

For students:

• Treat a late start as an opportunity for better rest and earlier academic work, not just more social time.

• Maintain a regular bedtime, even on nights without early obligations.

• Watch for creeping increases in alcohol use and late-night activity.

For colleges:

• Offer education on sleep hygiene and the risks of excessive alcohol use.

• Encourage balanced scheduling that avoids both extremely early and very late first classes.

• Provide quiet study spaces in the mornings to encourage productive use of time.

The Bottom Line

Late-start college classes offer the promise of more sleep — and in theory, more alert, higher-performing students. But in practice, the freedom they offer can lead to later bedtimes, more drinking, and weaker daily structure.

For some students, that means worse grades, even with extra rest. The lesson isn’t that late starts are bad for everyone, but that their success depends on how students use the flexibility. Sleep isn’t just about quantity; it’s about timing, quality, and the lifestyle choices that surround it.

In the end, the best academic results come when students combine healthy rest with consistent habits — whether their first class is at 8:00 a.m. or noon.

This article was created using OpenAI’s ChatGPT on August 15, 2025 and it was personally reviewed and edited by Brandon Peters, M.D. to ensure its accuracy. This use of augmented intelligence in this way allows the creation of health information that can be trusted.