Nothing disturbs your rest quite like an intensive sweating session. There are, after all, few things more uncomfortable than waking up drenched despite a comfortable mattress, a cozy comforter, and pleasant dreams. And if it’s happening with any sort of frequency, it can be a little bit alarming too. You may be wondering, why do I sweat in my sleep?
Generally speaking, night sweats are the result of relatively harmless and easy-to-fix issues, like the temperature of your bedroom or the material of your pajamas. And temperature fluctuation while you’re resting is very normal. “The body’s core temperature is typically between 97 and 99 degrees Fahrenheit, but it decreases during the nocturnal sleep phase, usually by 1.5 to 2 degrees,” explains Peter Polos, M.D., Ph.D., a sleep medicine specialist and sleep expert for Sleep Number. This is essential for quality sleep, as a decrease in core temperature is one of the triggers that make you sleepy.
If that isn’t happening, you may begin sweating profusely, which could be symptomatic of an underlying condition, says Neomi Shah, M.D., an associate professor of pulmonary and sleep medicine at the Icahn School of Medicine at Mount Sinai.
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It’s also important to keep in mind that for women, night sweats could really be hot flashes. “Hot flashes may be difficult to distinguish from night sweats,” says Juan J. Remos, M.D., the chief medical advisor and an internist for Gentera Center for Regenerative Medicine. “Hot flashes may begin with an unpleasant heat sensation in the chest, neck, or abdomen. A sudden warmth and visible skin redness in the chest, head, and neck follows.”
With hot flashes, the sensation of warmth can last anywhere from three to four minutes to 20 or 30 minutes, and is typically followed by sweating in the same areas. Hot flashes at night are typically described by women as night sweats, but they are different—hot flashes can occur at any time and likely won’t only come on at night, says Remos.
As a rule of thumb, if you’re finding that your night sweats are consistent over the course of two to three months, it’s worth paying a visit to your doctor, who can help diagnose the issue (if there is one). But before you panic, check out the most common causes of night sweats and how you can address them.
1. Your room is just too hot
What’s the temperature of your bedroom right now? If it’s anything other than 60 to 70 degrees Fahrenheit, it’s probably too hot, says W. Christopher Winter, M.D., a sleep specialist and the author of The Sleep Solution: Why Your Sleep Is Broken and How To Fix It.
Less breathable fabrics (like your flannel pajamas) can also contribute to your sweaty sleep woes. Breathable cotton is a better option for both your PJs and sheets.
Feeling hot can also impede your ability to actually fall asleep. In the process of drifting off, your body temperature should drop one to two degrees below normal, and it can’t do that in a warm room.
2. You have hyperhidrosis, an excessive sweating disorder
Yes, that’s a thing, and it essentially happens when a person sweats more than necessary (yes, including while they’re sleeping), according to the American Academy of Dermatology (AAD).
One big difference between hyperhidrosis and run-of-the-mill sweating: Hyperhidrosis typically affects specific body parts, per the AAD, like your palms, feet, underarms, and head. Keep in mind, though, this is excessive sweating—the AAD describes hyperhidrosis as excessive sweating that interferes with daily activities (like opening doorknobs or using computers) in those who have it.
If you think you have hyperhidrosis, talk to your dermatologist—they can prescribe specific deodorants or other methods of treatment, like Botox injections to block sweat glands, per the AAD.
3. You’re having nightmares
This is probably the simplest explanation for those sweats. Anything that causes “a sympathetic surge” (also known as a fight-or-flight response) can lead to sweating, per Shah. If you’re having ongoing, persistent nightmares, see your doctor to find out what might be causing it (stress is often a culprit).
4. Your body's going through hormonal changes, like those related to menopause
One of the most common causes of night sweats for women is fluctuating estrogen levels. “Menopause is associated with hot flashes, so it’s not uncommon for patients to report sweating even during their sleep,” Shah says. But again, these may occur at other times during the day as well.
If a women is pregnant or on their period, those hormone fluctuations could lead to night sweats too. However, menopause tends to cause the most persistent sweats, and if it’s truly affecting your quality of life or sleep, it’s worth talking to your doctor. “Sweating from menopause is unpredictable, but if you talk to your ob-gyn about hormone replacement therapy, it could help keep your temperatures under control,” says Shah.
5. You’re anxious
Your stress can follow you into bed, and that can manifest in excessive sweating. “Increased sweating can be a physical symptom of anxiety, which is caused by an activated fight-or-flight response,” explains Caroline Cederquist, M.D., a bariatric physician with a specialization in nutrition and metabolism and the founder of BistroMD. “The associated stress hormones increase energy expenditure and sweat is released to cool down body temperature.”
If you find yourself feeling restless or tense before bed, or experiencing a rapid heart rate and rapid breathing, you can try to alleviate some of these feelings of stress through pre-bedtime meditation, limiting screen time, and setting aside a period (30 minutes or so) for winding down before bed.
6. You’re exercising close to bedtime
When you exercise close to your bedtime, you can increase your metabolic rate, explains Polos. This, in turn, can result in your feeling warmer in the evening, especially if you’re a hot sleeper to begin with.
“Try to squeeze your workout in about two hours before you plan to go to bed,” Dr. Polos recommends.
7. You’re taking antidepressants
Patients taking antidepressants can definitely see an uptick in night sweats, Shah says, as certain classes of medications can cause an adrenergic reaction, which has to do with your adrenaline levels and leads to sweating. If you're taking venlafaxine (or Effexor) or bupropion (or Wellbutrin, Zyban, or Aplenzin), you may experience more night sweats, Shah says.
But there’s good news if you don't want to switch your antidepressant, as there are drugs docs can prescribe to calm down the adrenergic output, which won’t counteract your mental health care.
8. Your body’s fighting off an infection, like tuberculosis
“Infections in general are related to changes in temperature because they come with fevers that will break, and that is obviously a common reason to sweat,” Shah says.
One rare infection that’s commonly associated with night sweats: tuberculosis, which can infect any part of your body but is well known for its effect on your lungs. People with an immunocompromised condition, like HIV, can develop tuberculosis more easily, Shah says. You might start sweating in your sleep before you even start coughing or realize something is wrong, Shah says, so see a doc stat if the symptoms persist.
9. You have undiagnosed lymphoma
Lymphoma—a cancer of part of the immune system, according to the U.S. National Library of Medicine (NLM)—can cause multiple symptoms like fever, weight loss, and, yes, night sweats, says Shah. Essentially, your body recognizes lymphoma as something it needs to fight off and raises its temperature to try to do so.
While these “soaking sweats,” per the NLM, happen at night, heavy sweating might occur during the day too, so get to your M.D. if you’re experiencing any other symptoms and they can test you for the condition, says Dr. Shah.
10. You’re experiencing hypoglycemia related to your diabetes medication
Hypoglycemia occurs when blood sugar levels drop too low, and can cause a variety of symptoms including confusion, dizziness, and in some cases, night sweats. When your blood sugar level dips below a certain point, your body will use hormones, like cortisol, to try to preserve normal blood glucose levels and organ function, therefore activating the autonomic nervous system, which is in charge of your glands, explains Remos.
That activation can cause profuse sweating. Sometimes these sweats can come on suddenly and, when paired with confusion, may require the administration of glucose orally or intravenously, says Remos.
11. You have undiagnosed hyperthyroidism
Those with hyperthyroidism have an overactive thyroid that produces more thyroid hormone than the body needs. Thyroid hormone can affect the way the body uses energy, and some symptoms of it include muscle weakness, mood swings, and trouble tolerating heat, according to the NLM,
If you’re experiencing night sweats related to hyperthyroidism, they may happen on a consistent schedule as opposed to randomly and will usually appear with other symptoms of the condition, says Remos.
12. You have a rare tumor in the adrenal gland known as a pheochromocytoma
Pheochromocytomas are rare, usually benign tumors that start in the cells of the adrenal gland, according to the NLM. The symptoms associated with these tumors are episodic headaches, sweating, and tachycardia, which is a rapid heartbeat, says Remos.
These symptoms are usually caused by the excess release of hormones like adrenaline and epinephrine by the tumor, which in turn may be causing you to dampen your bedsheets at night. “The night sweats are triggered by the excess adrenaline type hormones,” Remos says.
13. You're experiencing a hormone disorder, like undiagnosed carcinoid syndrome
Night sweats are a common symptom of hormone disorders, since they tend to throw the body’s functions out of whack. One hormone disorder that can lead to night sweats is carcinoid syndrome, which refers to a group of symptoms experienced by people with carcinoid tumors, which can appear all over but tend to originate in the digestive tract.
“Getting flushed is the hallmark of the carcinoid syndrome, occurring in 84 percent of affected patients; sweating may occur concurrent with the flushing,” says Remos. “Flushing is an increased blood flow to the skin due to vasodilation and is experienced as a warmth and redness of the face and occasionally the trunk, which may be associated with sweating.”
14. You’re dealing with an undiagnosed neurologic condition, like post-traumatic syringomyelia
Like hormone conditions, neurologic conditions, particularly spinal cord injury and syringomyelia, says Remos, can also cause night sweats. “The autonomic nervous system exerts involuntary control over smooth muscle like the intestine or the pupil, and glands. Damage to the spinal cord causes it to malfunction and stimulate sweat glands inappropriately,” he says.
Post-traumatic syringomyelia, specifically, refers to the formation of cysts in the spinal cord and can cause episodes of increased sweating.
Remedies for Night Sweats
If your symptoms are mild and do not interfere with normal activities, Remos recommends simple behavioral changes, like lowering the room temperature, using fans, or dressing in layers you can easily shed. You should also avoid things that may trigger sweating, like spicy foods, and try to keep stress to a minimum. Your derm can also help prevent the sweats, either by recommending clinical-strength antiperspirants or Botox injections.
If you’re dealing with moderate to severe night sweats or hot flashes related to menopause, Remos says you may want to look into menopausal hormone therapy, which uses hormones to treat the symptoms, including hot flashes. It isn’t a good treatment for everyone, as it can be risky to those with conditions like coronary heart disease or a history of breast cancer, so talk with your doctor about your options.
For certain conditions, taking medication that treats the condition may also treat some of the symptoms related to it, so always consult your doctor if you think there’s something new going on with your body and you need relief.
Jasmine Gomez is the Associate Commerce Editor at Women’s Health and covers health, fitness, sex, culture and cool products. She enjoys karaoke and dining out more than she cares to admit.
Emily Shiffer is a former digital web producer for Men’s Health and Prevention, and is currently a freelancer writer specializing in health, weight loss, and fitness. She is currently based in Pennsylvania and loves all things antiques, cilantro, and American history.