Why Do I Sweat in My Sleep? Experts Share 7 Possible Reasons

Heat and Humidity

If your sleep environment is too warm, your body will sweat while you sleep. It may sound obvious, but it’s not always easy to get the temperature right, according to Wu, who is a medical reviewer for the Rise Science sleep health app.

Monitor your room temperature and humidity to see if it's the cause of sweating in your sleep. “Keep your bedroom cool, around 65 degrees, crack your window, or use a fan,” Barnett suggests.

Everything from your pajamas to your bedding to the weather will affect the temperature of your sleep environment. Plus, Wu explains that our body temperature fluctuates throughout the night—meaning you may be cool enough at one point and sweating at another.

Fabric Choice

Similarly, pay attention to your nightwear and bedding. “You don't want to overdress, and make sure to pick breathable and moisture-wicking fabrics for both bedding and nightwear,” Barnett tells us. That means avoiding fabrics like polyester, nylon, and cotton and instead sticking to wool, linen, bamboo viscose, lyocell, and hemp. Ensure your blankets and sheets are suited for the season, and consider switching out your duvet depending on the weather—a light wool or down-filled duvet may be best during warmer months.

Alcohol Before Bed

The nightcap that helps you drift off may actually be waking you up in the night and causing you to sweat more than usual, according to Wu. “Alcohol increases your heart rate and relaxes your airways, making it harder to breathe—both of which can increase your body temperature, making you sweat,” he says.

Barnett explains this is because drinking alcohol affects your nervous system, causing a response in blood pressure, heart rate, and body temperature, which could trigger the release of sweat. Try swapping your last drink of the night for a different calming beverage like tea, turmeric milk, or tart cherry juice, and see if that helps.

Stress and Anxiety

If none of the above causes are factors in your life but you're suddenly sweating in your sleep more than usual, check your stress and anxiety levels. “When you are very stressed, your brain reacts, causing physiological changes in your body, both increasing heart rate and releasing hormones,” Barnett says. These responses can lead to increased sweating. 

“[Stress-related sweating] can happen during the night and day; many people might notice this before a job interview or an important presentation at work,” Barnett tells us. “Trying to have some time to wind down before going to sleep should help you lower your stress levels and reduce sweating as well.” Small changes—like reducing your screen time before bed and integrating calming rituals into your nightly routine—can help you fall asleep in a more relaxed (and less sweaty) state.

Wu also cautions that stress can cause nightmares and panic attacks at night, which can lead to excessive sweating. Check in with your healthcare provider if you're more stressed or anxious than usual.

Medication Side Effects

Some medications might lead to increased sweating as a side effect. This can especially happen with things like antidepressants or diabetes treatments, according to Barnett. Wu adds that other meds that can induce sweating at night include painkillers and some dietary supplements, like calcium and niacin. 

“If you believe that a medication you are taking leads to increased night sweating, you should contact your doctor to discuss [whether] and how to adapt dosage or evaluate alternatives,” Barnett says.

Hormonal Fluctuations

Hormonal changes can be a significant cause of sweating at night. “If you're going through menopause or even due to hormonal changes during the menstrual cycle, you might experience increased sweating,” Barnett says. She suggests that to cool yourself down, you could try to uncover your extremities, such as your feet and neck, or place a cool washcloth on your head.

Hot flushes, also called hot flashes, are a common menopause symptom caused by changing hormone levels. “They can happen at any time of the day and night, and they usually last for a few minutes, leaving you hot, red, and sweaty,” Wu says. Women can also experience hot flushes in the transition period before menopause, also called perimenopause, and during pregnancy or after birth.

Medical Conditions

If none of the above seem to be causing your night sweats, consider your medical history or discussing the issue with a doctor, as certain conditions can cause you to sweat in your sleep more than usual. “One possible cause, although very rare, is a sweating disorder called hyperhidrosis, which leads your body to produce excessive sweat for unknown reasons,” Barnett says. This isn't a serious condition, but it can be frustrating. Wu says that other conditions that can cause sweating include hypoglycemia (low blood sugar), hormone disorders like hyperthyroidism (overactive thyroid), bacterial infections, gastroesophageal reflux disease (GERD), autoimmune disorders like rheumatoid arthritis, neurological conditions, and some cancers, like leukemia and Hodgkin's lymphoma. 

Night sweats are also a common symptom of obstructive sleep apnea, the sleep disorder that causes airways to relax and breathing to stop momentarily during sleep. If you wake up feeling short of breath or as if you stopped breathing for a moment, it’s crucial to see your doctor.