Why Do You Sweat So Much at Night? MDs Explain What’s Really Going On

Few things are worse than waking up drenched in the middle of the night, one leg hooked outside of the duvet, sweating as if you’ve just run a marathon. According to the Sleep Foundation an estimated 41 percent of people experience these kinds of night sweats, with research published in the Journal of the American Board of Family Medicine putting these numbers closer to 60 percent for some women. Night sweats may be a fairly common frustration, but that doesn’t mean they’re pleasant to endure – and there’s several reasons why they might occur.

While they’re not necessarily indicative of a larger medical issue, considering that they can disrupt your sleep and seriously soak your sheets, night sweats could be worth investigating further. To learn more about why you’re sweating in your sleep, we spoke to experts about some of the most common causes, including hormonal imbalances and infections. Read on to find out why you sweat when you sleep, plus some ways to potentially sweat less and get a better night’s rest.

Experts Featured in This Article:

Sherry Ross, MD, FACOG, is an ob-gyn and women’s health expert at Providence Saint John’s Health Center.

Kristine Arthur, MD, is an internist at MemorialCare Orange Coast Medical Center.

Why Do I Sweat So Much at Night?

Night sweats can occur for a variety of reasons. Here are some of the most common reasons you may be sweating so much at night – according to experts.

1. Hot Flashes: The condition most commonly associated with night sweats is hot flashes, which can occur at any time during your menstrual cycle – day or night. And while people tend to hear “hot flashes” and think “menopause,” they can occur for other reasons. “Any hormone event that causes a significant decrease in estrogen affects the body’s thermostat in the hypothalamus, which controls body temperature and can lead to hot flashes,” says Sherry Ross, MD, FACOG. While estrogen decreases leading up to menopause, it can also dip during your monthly cycle – typically around the first day of your period, or a few days prior.
2. A Hormone Imbalance: Other hormonal imbalances can also cause night sweating, explains Kristine Arthur, MD. These include hyperthyroidism and adrenal disease, which occur when the body doesn’t produce enough cortisol or aldosterone. While your monthly cycle may be to blame for periodic night sweats, if you find it happens more frequently, it’s worth making an appointment with your doctor to rule out other causes like these. “Both of these conditions can be detected with blood and urine testing in your doctor’s office and successfully treated with medications or other treatments,” Dr. Arthur says.
3. Low Blood Sugar: Low blood sugar (or hypoglycaemia) may be another culprit of night sweats, especially for people with diabetes. Blood sugar can drop while you’re asleep, causing tiredness, headaches, and damp sheets from sweat, per the United Kingdom National Health Service (NHS). If you have other symptoms of diabetes, such as increased thirst, frequent urination, or sweet-smelling urine, consider visiting your doctor.
4. New Medications: Certain medications, such as antidepressants, can also result in night sweats, Dr. Arthur says. Drugs used to treat low blood sugar (hypoglycemic agents) and hormone therapy may cause you to wake up drenched as well, according to the Mayo Clinic. If you’ve started a new medication recently, it could be worth asking your healthcare provider if it’s associated with night sweats, and if there’s anything you can do to alleviate the symptoms.
5. Infection: In some cases, night sweats can be a sign of infection, including tuberculosis, bacterial infections, and conditions related to the nervous system or the body’s hormone-producing glands (endocrine system). Similarly, if you’ve been sick recently, you may experience night sweats while your body recovers. If the night sweats are new and accompanied by fever, change in appetite, weight loss, rash, or swollen lymph nodes, this may be a sign to contact your healthcare provider.
6. An Underlying Medical Condition: In some cases, night sweats can be caused by a more serious medical condition or disease. These include (but are not limited to): autoimmune disorders like rheumatoid arthritis, certain types of cancer like leukemia, anxiety disorders and depression, heart disease, HIV/AIDS, hyperthyroidism (also known as an overactive thyroid), sleep disorders (including obstructive sleep apnea), and stroke. That’s why if you experience the issue persistently, it’s a good idea to get it checked out by a doctor.

How to Stop Night Sweats

Again, if you suspect an underlying condition is causing night sweats, you should see a healthcare provider for further evaluation. Otherwise, taking steps to maintain your body temperature throughout the night is one of the first lines of defense against night sweats. To keep cool through the night, the Cleveland Clinic recommends the following:

• Sip cool water throughout the night.
• Use pillows and mattress covers containing cooling gels.
• Wear loose-fitting pajamas designed for better sleep.
• Use lightweight, layered bedding that you can remove throughout the night.
• Use a bedroom fan, sleep with your windows open, or crank up the air conditioning.
• Keep a cold pack under your pillow, then flip your pillow to rest your head on a cool surface.

You can also help regulate your body temperature with simple steps leading up to bedtime. Exercise daily (but not immediately before bed), and take time to unwind before bed using deep breathing, relaxation, and meditation techniques. Avoid common night sweat triggers such as alcohol, spicy foods, caffeine, and cigarettes. But it bears repeating: if night sweats are a new symptom, it’s worth flagging to your healthcare provider, especially if the sweats are happening regularly and disrupting your sleep.

– Additional reporting by Chandler Plante

Colleen Travers is a PS contributor.

Chandler Plante is an assistant editor for PS Health & Fitness. Previously, she worked as an editorial assistant for People magazine and contributed to Ladygunn, Millie, and Bustle Digital Group. In her free time, she overshares on the internet, creating content about chronic illness, beauty, and disability.