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 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.

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.