Even in the middle of winter, you may wake up covered in sweat, with your blanket or comforter hanging off the bed. If you have been wondering why this occurs, you are not alone. Your body has a unique set of systems that help it regulate throughout the day and while you sleep, and several of them behave differently at night. Here is what is going on, the nine most common reasons, and when it is worth a call to your doctor.
Why do I get so hot when I sleep?
You get hot when you sleep because your body has to shed heat to fall and stay asleep, and anything that traps that heat against you, from bedding and sleepwear to hormones, medication or illness, leaves you overheated and sweating. Core body temperature follows a daily rhythm. It drops in the evening as you get drowsy, by around 1.8 degrees Fahrenheit over the night according to the Sleep Foundation, and you are most likely to fall asleep while it is falling fastest. That heat has to go somewhere. It leaves through your skin, into whatever you are wearing and lying under. When it cannot escape, you wake up hot.
Nine reasons your body gets so hot at night
1. Thermoregulation is doing its job
Thermoregulation, the process of keeping the body at optimum temperature, is one reason why you may wake up feeling overheated or sweaty. To bring your core temperature down at bedtime, your body pushes warmth out to the skin. That is the warm hands and feet feeling as you drift off, and it is normal. If the air, your pajamas and your covers hold that warmth against you, the drop stalls and you feel hot instead of sleepy.
2. REM sleep runs warmer
Brain temperature rises during REM sleep, which can affect the temperature of the body and its surroundings. Research on the temperature dependence of sleep shows the brain cools as you move into deep sleep and rewarms as you move back into REM or toward waking. Those rewarming phases are when a bed that holds heat catches up with you.
3. Your bedroom, bedding and sleepwear
This is the most common cause and the easiest to change. The Sleep Foundation puts the best room temperature for sleep at around 65 to 68 degrees Fahrenheit and warns against insulating bedding such as fleece. Sleepwear matters just as much. A dense fabric that holds moisture keeps you wet and warm whatever fiber it is made from, while a fabric built to move sweat away from the skin lets your body finish cooling.
4. Hormones: perimenopause, menopause, pregnancy and postpartum
Night sweats and hot flashes are common symptoms among women with menopause. Cleveland Clinic notes that night sweats happen more often in women because estrogen and progesterone help the body control its temperature, and when those levels rise or fall the body may struggle to stay comfortable and sweats to cool down. The same shifts drive the sweats of perimenopause, pregnancy and the postpartum weeks. If that is you, our guide to the science of night sweats in women goes deeper.
5. Low testosterone in men
Night sweats can occur in men when testosterone levels drop, and hormone-disrupting treatments for prostate cancer are a known trigger. We cover the male side in why men overheat at night.
6. Medications
Antidepressants are the most common medication behind excessive sweating, and Cleveland Clinic also lists blood pressure medications, some migraine medications, pain relievers including ibuprofen and narcotics, steroids and breast cancer treatments. If the sweating started around the time a prescription changed, that is worth raising with whoever prescribed it. Do not stop a medication on your own.
7. Illness and infection
Conditions such as fevers can cause you to feel overheated during sleep. Bacterial and viral infections including the flu and COVID-19 can bring night sweats while your body fights them, and conditions that interfere with temperature control, such as an overactive thyroid or diabetes, can do the same.
8. Stress and anxiety
Anxiety, panic and even constant everyday stress can trigger sweating in your sleep. The nervous system that runs your fight or flight response also controls your sweat glands, and it does not clock off at bedtime.
9. What you did before bed
Those who engage in rigorous exercise before bed may also experience a significant increase in sleep temperature. Alcohol, spicy food and caffeine in the evening have the same effect, and the National Institute on Aging singles out all three as things that make night sweats worse.
Why does my body get so hot at night, especially as a woman?
Women get hot at night more often than men because estrogen and progesterone are part of how the body sets its temperature, and those hormones move the most during perimenopause, menopause, the menstrual cycle, pregnancy and the postpartum weeks. Cleveland Clinic lists all five as hormonal causes of night sweats. It is also why the problem can start years before your periods stop, and why it can appear out of nowhere after a baby.
Why are hot flashes worse at night?
Hot flashes feel worse at night because they arrive while your body is already working to shed heat, in a bed that holds it. The National Institute on Aging simply calls a hot flash that happens at night a night sweat. During the day a flush passes and the air takes the heat away. At 2 a.m. the same flush lands under a comforter, in sleepwear that may be holding the sweat against you, and it wakes you up drenched.
Why am I so hot at night even in winter?
You can be hot at night in winter because the heat is coming from you, not from the weather. Your body is trying to drop its temperature to sleep whatever the season, and winter bedrooms usually work against it: the heating stays on, the comforter gets heavier, and the layers pile up. If you sweat through the night in January, the room and the covers are the first thing to look at.
When to see a doctor about sleeping hot
If you are not of menopausal age, or have other reasons (a new medication, for instance) to believe that your sleeping temperature is too high, consider consulting your doctor. The NHS advises seeing a doctor if you regularly have night sweats that wake you up or worry you, if they come with a very high temperature, a cough or diarrhea, or if you are losing weight for no reason. Night sweats on their own rarely need treatment, but a doctor will want to rule out the causes above.
How to stay cooler when you sleep
- Turn the bedroom down. Aim for the 65 to 68 degree range, open a window on cooler nights, and run a fan.
- Layer the bedding. Use layers you can push off during the night rather than one heavy comforter, and skip insulating fabrics.
- Wear sleepwear that moves sweat off your skin. Light, loose clothing is the standard advice. Cool-jams NightCool sleepwear is made for night sweats and hot flashes: the fabric wicks sweat away from the skin and keeps the fabric breathable through the night, so you are not lying in a damp shirt waiting to cool down. See women's cooling pajamas, menopause pajamas and men's NightCool sleepwear, or read our guide to the best cooling pajamas for hot sleepers.
- Keep evenings quiet. Move hard workouts, alcohol, spicy food and caffeine earlier in the day.
- Keep cold water by the bed. Cleveland Clinic and the National Institute on Aging both suggest it, small sips before bed and during a sweat.
For the physiology behind all of this, see why body temperature changes while you sleep, and if the sweating is regular, the real causes of night sweats in women and when to see a doctor.
Sources
- Sleep Foundation, Why Do I Get So Hot When I Sleep?, medically reviewed by Abhinav Singh, MD.
- Cleveland Clinic, Night Sweats, medically reviewed, last updated April 28, 2026.
- NHS, Night sweats, reviewed November 9, 2023.
- National Institute on Aging, Hot Flashes: What Can I Do?
- Harding EC, Franks NP, Wisden W. The Temperature Dependence of Sleep. Frontiers in Neuroscience, 2019.
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