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.

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 Sleep Changes During Pregnancy: What to Expect Trimester by Trimester

Sleep is something we often take for granted—until it becomes elusive. For many women, pregnancy brings unexpected challenges when it comes to getting a good night’s rest. While some may assume sleep disturbances only happen in the third trimester, the reality is that sleep changes throughout pregnancy, starting as early as the first few weeks.

In this post, we’ll break down how and why your sleep might change across each trimester, what causes those disruptions, and how you can manage them for a healthier, more restful pregnancy.

🌙 First Trimester (Weeks 1–12): Surprising Sleepiness and Strange Dreams

What Happens to Sleep?

In the first trimester, many women feel overwhelmingly tired—even if they’re sleeping more than usual. That exhaustion stems from a surge in progesterone, a hormone that supports early pregnancy and also has a natural sedative effect. You might find yourself napping during the day or struggling to keep your eyes open in the afternoon.

However, paradoxically, some women also report insomnia, vivid dreams, and frequent nighttime awakenings during this time.

Common Sleep Disruptions:

• Increased fatigue during the day

• Frequent nighttime urination due to hormonal changes

• Breast tenderness making it uncomfortable to sleep in usual positions

• Nausea (especially if it strikes at night)

• Emotional changes or anxiety interfering with falling asleep

Tips for Better Sleep in the First Trimester:

• Nap if needed, but keep naps under 30 minutes to avoid nighttime wakefulness

• Drink fluids early in the day, and taper off in the evening

• Use supportive pillows to ease breast discomfort

• Practice calming bedtime rituals—meditation, light reading, or a warm bath

🌜 Second Trimester (Weeks 13–27): The Sleep "Sweet Spot"

What Happens to Sleep?

For many women, the second trimester is a bit of a reprieve. Morning sickness usually fades, energy levels improve, and hormonal swings stabilize somewhat. This can make it easier to sleep soundly at night and feel more like yourself during the day.

However, not all sleep disturbances vanish. Heartburn, leg cramps, and the beginnings of a growing belly can still cause occasional trouble.

Common Sleep Disruptions:

• Mild heartburn or indigestion

• Leg cramps or restless leg syndrome (RLS)

• Back pain or mild discomfort from a growing belly

• Increased vivid dreaming or nightmares

Tips for Better Sleep in the Second Trimester:

• Begin sleeping on your left side, which promotes better circulation to your baby

• Place a pillow between your knees or under your belly for support

• Eat smaller meals to reduce heartburn

• Stretch gently before bed to prevent leg cramps

🌘 Third Trimester (Weeks 28–40): When Sleep Gets Tough

What Happens to Sleep?

The third trimester is when sleep challenges really peak. As your baby grows and your body prepares for labor, both physical and emotional discomforts make it harder to fall—and stay—asleep.

You might find yourself waking up multiple times a night, tossing and turning, or simply lying awake due to discomfort or anxiety.

Common Sleep Disruptions:

• Frequent urination, sometimes every hour

• Back pain and general discomfort from baby’s position

• Kicks or fetal movements that wake you up

• Heartburn or acid reflux

• Anxiety about labor, delivery, or parenthood

• Snoring or mild sleep apnea, due to nasal congestion and weight gain

Tips for Better Sleep in the Third Trimester:

• Sleep propped up with extra pillows to ease heartburn

• Try prenatal yoga or light stretching to reduce tension

• Avoid spicy or acidic foods close to bedtime

• Use white noise or calming sounds to help you relax

• Talk to your doctor if snoring or sleep apnea becomes frequent

🧘‍♀️ Safe Sleep Strategies for All Trimesters

No matter where you are in your pregnancy, a few consistent habits can support better sleep:

✅ Create a Relaxing Bedtime Routine

Signal to your brain that it’s time to wind down with calming rituals: dim the lights, avoid screens, read a book, or try guided meditation.

✅ Avoid Sleep Aids Unless Prescribed

While it may be tempting to reach for an over-the-counter sleep aid, always consult your healthcare provider first. Many common medications are not safe during pregnancy.

✅ Stay Active (But Not Too Late)

Regular, moderate exercise during the day can improve sleep—but avoid intense workouts too close to bedtime.

✅ Manage Worries

Pregnancy brings big changes, and anxiety is normal. Journaling, talking to a friend, or seeing a therapist can help reduce bedtime overthinking.

🩺 When to Talk to Your Doctor

Occasional sleep disruptions are normal during pregnancy, but chronic insomnia, extreme fatigue, or symptoms like severe snoring or leg jerking may point to deeper issues, such as:

• Sleep apnea

• Restless leg syndrome

• Prenatal depression or anxiety

Always discuss persistent sleep problems with your doctor or midwife—they may refer you to a sleep specialist or recommend safe, pregnancy-appropriate treatments.

🛌 Final Thoughts

Sleep and pregnancy have a complicated relationship. From first-trimester fatigue to third-trimester discomfort, each stage brings its own unique sleep challenges.

While you can’t prevent all sleep disturbances, understanding what to expect—and how to adapt—can make a big difference in your comfort and overall well-being.

Remember: you're growing a whole new human. Be gentle with yourself, rest when you can, and don’t hesitate to ask for help. Sleep may be elusive at times, but your body (and your baby) will thank you for every hour you can get.

📣 What’s Been Your Experience with Sleep During Pregnancy?
Let us know in the comments! Sharing your story could help another mama-to-be feel less alone.

This article was created using OpenAI’s ChatGPT on July 11, 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.

💤 Can Insomnia Be an Early Sign or Symptom of Pregnancy?

Pregnancy is a life-changing journey, and with it come a variety of emotional and physical changes—some expected, some surprising. While most people associate later stages of pregnancy with sleep troubles, some women notice something odd even earlier: insomnia.

But can insomnia really be an early sign of pregnancy? Let’s explore the science, symptoms, and what you can do if you're struggling to sleep during those early weeks.

🧠 What Is Insomnia?

Insomnia is the inability to fall asleep, stay asleep, or return to sleep after waking. It can be acute (short-term) or chronic (long-lasting), and it’s caused by a wide variety of factors:

• Stress

• Hormonal shifts

• Medical conditions (i.e., sleep apnea, pain)

• Lifestyle habits (i.e., caffeine, alcohol, napping)

When you're trying to conceive—or unexpectedly find yourself feeling “off”—sudden sleep disturbances may be one of your body's earliest hints.

🌙 Is Insomnia an Early Pregnancy Symptom?

Although it’s not one of the most common signs of early pregnancy like nausea or a missed period, some women do experience insomnia in the first few weeks. Here's why:

1. Hormonal Changes

Pregnancy triggers a surge of hormones, including progesterone and estrogen:

• Progesterone can make you sleepy during the day but cause fragmented or restless sleep at night.

• Estrogen influences sleep-regulating neurotransmitters like serotonin, which can affect your ability to fall asleep.

2. Increased Urination

The pregnancy hormone hCG increases blood flow to your kidneys, making you urinate more often—even in the first few weeks. Frequent nighttime bathroom trips can seriously disturb your sleep.

3. Anxiety and Emotional Changes

Even in a planned pregnancy, early emotions can be intense. Worries about the future, the baby’s health, or life changes ahead can cause racing thoughts, making it hard to drift off.

4. Mild Physical Discomfort

Tender breasts, bloating, and light cramping are all normal early signs of pregnancy. These symptoms, while not intense, can make sleeping difficult or uncomfortable.

5. Increased Body Temperature

Many women notice a rise in basal body temperature after ovulation and into early pregnancy. Feeling warmer at night or sweating more than usual can affect sleep quality.

🤔 Could It Be Something Else?

Not every case of insomnia signals pregnancy. Sleep issues are incredibly common and can be caused by:

• Stress or lifestyle changes

• Diet (caffeine, alcohol)

• Screen time before bed

• Menstrual cycle fluctuations

However, if your insomnia is accompanied by symptoms like:

• Missed period

• Fatigue

• Nausea

• Breast tenderness

• Mood swings

• Mild pelvic cramping

…it might be worth taking a pregnancy test.

📊 How Common Is Early Pregnancy Insomnia?

While most studies focus on sleep problems in the second and third trimesters, many women report changes in their sleep in the first few weeks.

Sleep disruptions—including trouble falling asleep and night waking—are very common throughout pregnancy, beginning as early as the first trimester.

🛏️ Tips for Managing Insomnia in Early Pregnancy

If you're pregnant—or think you might be—and insomnia is keeping you up, here are some natural, pregnancy-safe tips to help you sleep better:

1. Practice Good Sleep Hygiene

• Stick to a consistent sleep schedule

• Avoid screens 30–60 minutes before bed

• Keep your bedroom cool, dark, and quiet

2. Limit Fluids in the Evening

Drink plenty of water during the day, but reduce your intake in the evening to prevent frequent nighttime bathroom trips.

3. Try Relaxation Techniques

• Deep breathing

• Meditation apps

• Prenatal yoga

• Progressive muscle relaxation

4. Eat Smart

Avoid heavy meals late at night. Eat a light, protein-rich snack if nausea or hunger is waking you up.

5. Manage Anxiety

Talk to a friend or partner about your worries. Journaling or seeking support from a counselor can help reduce nighttime overthinking.

🩺 When to Call a Doctor

If you’re experiencing chronic insomnia—trouble sleeping for more than three nights a week for several weeks—or if sleep issues are causing severe fatigue, mood swings, or anxiety, it’s time to consult your doctor.

There are safe and effective treatments for sleep issues during pregnancy, including cognitive behavioral therapy for insomnia (CBTI) and lifestyle adjustments. Avoid taking over-the-counter sleep aids unless recommended by your healthcare provider.

✅ Final Thoughts

So, can insomnia be an early sign of pregnancy? Yes—it can, for some women. Hormonal changes, emotional shifts, and early physical symptoms can all contribute to disrupted sleep in the first few weeks.

However, insomnia on its own isn't a definitive sign of pregnancy. If it’s accompanied by other early symptoms, it may be worth testing and speaking with your doctor.

Regardless of the cause, quality sleep is essential—especially during pregnancy. Prioritize rest, listen to your body, and don’t hesitate to seek support if you're struggling.

This article was created using OpenAI’s ChatGPT on July 11, 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.

Why Do We Get Sweaty in Sleep?

Waking up drenched in sweat, even when the room isn’t particularly warm, can be both uncomfortable and confusing. Sweating during sleep is a common experience that affects people of all ages. In most cases, it’s harmless and the result of natural body processes. But in some situations, it could point to an underlying issue that needs attention. So, why do we get sweaty in our sleep?

To understand nighttime sweating, or sleep hyperhidrosis, it’s important to look at how our body regulates temperature, what factors can disrupt this balance during sleep, and how medical or environmental triggers might contribute. While occasional sweating at night is typically benign, frequent or excessive episodes may indicate something deeper.

The Body’s Thermoregulation System

The human body has a sophisticated internal system for regulating temperature, known as thermoregulation. This process keeps the body’s core temperature within a narrow, healthy range—around 98.6°F (37°C)—regardless of external conditions. The brain’s hypothalamus acts as the control center, directing the body to cool down or warm up as needed.

Sweating is one of the body’s primary cooling mechanisms. When body temperature rises above a certain threshold, sweat glands release fluid onto the skin’s surface. As this fluid evaporates, it cools the body. During the day, we’re usually aware of sweating in response to exercise, stress, or hot weather. At night, though, the process continues largely unnoticed—unless it becomes excessive.

Natural Causes of Nighttime Sweating

There are several non-medical reasons you might sweat while sleeping. These are typically environmental or lifestyle-related and can often be resolved with simple changes.

1. Room Temperature and Bedding

One of the most common reasons for nighttime sweating is simply overheating. If your bedroom is too warm or your bedding is too heavy, your body may struggle to cool itself, resulting in sweating. Materials like flannel sheets or foam mattresses can trap heat close to the body, raising skin temperature and triggering sweat production.

2. Sleep Position and Body Heat

Sleeping in certain positions—such as curled up tightly or lying against a partner—can trap heat and reduce airflow, contributing to localized sweating. Some people naturally generate more body heat, especially during deeper stages of sleep, when the body becomes less responsive to external temperature changes.

3. Nighttime Eating or Drinking

Consuming heavy meals, alcohol, or spicy foods before bed can raise body temperature. Alcohol in particular causes blood vessels to dilate, increasing warmth and prompting the body to cool itself through sweat. Similarly, caffeine or nicotine before bed can overstimulate the nervous system, leading to restlessness and sweating.

Hormonal and Physiological Causes

There are also biological and hormonal factors that may cause sweating during sleep.

1. Hormonal Fluctuations

One of the most well-known causes of nighttime sweating—especially in women—is hormonal changes. Menopause, perimenopause, and even certain phases of the menstrual cycle can lead to hot flashes, which often occur during sleep. These hot flashes are caused by fluctuations in estrogen levels and can trigger sudden feelings of heat, flushing, and profuse sweating.

Similarly, low testosterone levels in men, often due to age or hormonal disorders, can also contribute to excessive sweating.

2. Fever and Illness

Infections or fever-causing illnesses can result in night sweats as the body fights off the pathogen. This kind of sweating is usually more intense than typical overheating and is often accompanied by chills, fatigue, or other symptoms.

Stress, Anxiety, and Nightmares

The nervous system plays a key role in regulating sweat. When a person is stressed or anxious—even while sleeping—the body can go into “fight or flight” mode, triggering a surge in adrenaline and causing sweating. People who suffer from chronic stress, anxiety disorders, or frequent nightmares are more prone to waking up sweaty.

Night terrors, common in children but possible in adults, are another cause. These intense episodes of fear during sleep can cause physical reactions like increased heart rate, heavy breathing, and sweating.

Medications and Medical Conditions

Some medications have side effects that include night sweats. These include:

• Antidepressants, particularly SSRIs and SNRIs

• Hormonal therapies (like estrogen or testosterone treatments)

• Fever reducers such as aspirin or acetaminophen

• Corticosteroids

• Certain diabetes medications

Additionally, several medical conditions can cause excessive nighttime sweating. These include:

• Hyperthyroidism, where an overactive thyroid increases metabolic rate and body heat

• Diabetes, particularly during nighttime hypoglycemia (low blood sugar)

• Gastroesophageal reflux disease (GERD), which can provoke sweating during sleep

• Cancers, particularly lymphoma, which often presents with drenching night sweats

• Sleep apnea, a disorder that causes pauses in breathing and frequent awakenings, can be associated with sweating as the body reacts to oxygen deprivation

When to See a Doctor

Occasional night sweating, especially if linked to room temperature or lifestyle, is generally not a cause for concern. However, you should seek medical advice if you experience:

• Frequent or severe night sweats

• Unexplained weight loss

• Fever or persistent fatigue

• Night sweats despite a cool, comfortable environment

A doctor may perform blood tests, imaging, or sleep studies to determine whether an underlying condition is contributing to your symptoms.

Managing and Preventing Night Sweats

If your night sweats are not tied to a medical issue, some simple strategies can help manage them:

• Keep your bedroom cool, ideally between 60–67°F (15–19°C)

• Use breathable bedding and moisture-wicking sheets

• Avoid heavy or synthetic pajamas

• Reduce alcohol, caffeine, and spicy food intake before bed

• Practice stress-reduction techniques like mindfulness, meditation, or deep breathing

• Stay hydrated to support your body’s cooling mechanisms

Conclusion

Getting sweaty in your sleep can be annoying or even alarming, but it's often the result of natural processes like thermoregulation, hormonal shifts, or environmental factors. When it happens occasionally, it’s usually nothing to worry about. But if it becomes frequent, intense, or is accompanied by other symptoms, it may point to an underlying health issue worth investigating.

Understanding the many causes of sleep-related sweating can help you take control of your environment, reduce discomfort, and ensure a more restful, dry night’s sleep.

This article was created using OpenAI’s ChatGPT on May 16, 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.