What Are Night Sweats—And What Causes Them? Here's What Experts Say

Night sweats are more than just feeling warm and uncomfortable under the covers.

Ever wake up drenched in sweat, with the sheets and your nightclothes damp to dripping wet? If it happens once or twice and then stops with no known cause, you can probably just blow it off. But if it happens routinely, you're suffering from night sweats, or excessive to extreme perspiration while you sleep.

Recognizing that you're having night sweats is easier than uncovering what the underlying cause is. Several factors—some benign, others that point to something serious—can leave people experiencing this uncomfortable, sleep-disruptive symptom. Here's everything you need to know about what night sweats feel like, what causes them, and how to treat them and sleep more comfortably.

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What Do Night Sweats Feel Like?

Night sweats can feel different from person to person. But generally speaking, they happen in repeated episodes over time (and even on the same night), and they tend to be more severe than simply being in a toasty room.

Night sweats typically come on suddenly and last for a few minutes, often accompanied by chills afterward. "It can feel like a build-up and explosion of heat, a rush of adrenaline, a wave of heat, the list goes on," Colorado-based ob-gyn Sara Lillo, MD, a member of the medical team at digital health platform Nurx, tells Health.

On the other hand, some people won't feel them at all—you might even sleep through them. If the sweating doesn't wake you, you may notice uncomfortable dampness when you do wake up, Dr. Lillo says. That dampness can range from mild to drenching, Stephanie S. Trovato, MD, assistant professor of dermatology at The Ohio State University Wexner Medical Center, tells Health.

Milder nighttime perspiration is less likely to indicate an underlying disease or infection, Dr. Trovato says. On the other hand, "severe, drenching sweats should raise an alarm for further evaluation," she explains.

What Causes Night Sweats?

Experts agree: night sweats can happen for many reasons. Night sweats are a symptom with causes ranging from menopause all the way to cancer, Dr. Lillo says. Here are a few of the more common reasons for night sweats.

  • Medical conditions. A variety of medical conditions, including cancer, can cause night sweats, Dr. Lillo says. Infections like the flu can also lead to night sweats and are often accompanied by other symptoms, like fever. Mental health conditions can also be a factor; anxiety and stress are additional reasons night sweats happen.
  • Hormonal issues. Menopausal hot flashes and endocrine disorders (including thyroid disease and diabetes), can be behind nighttime sweating. "Changing levels of hormones in your body are a very common cause of night sweats," New York City-based family medicine physician Eric Michael Ascher, DO, tells Health.
  • Certain medications. "There's a lot of different medications that have side effects of night sweating," Dr. Ascher points out—including antidepressants, blood pressure medications, steroids, and even everyday over-the-counter meds like aspirin and Tylenol.
  • Behavior. Though lifestyle habits aren't always a common cause of night sweats, eating spicy food, drinking a hot beverage or alcoholic drink before bed, or even taking a steamy shower can bring them on, Dr. Ascher says.
  • Idiopathic hyperhidrosis. "Idiopathic" means that the cause is unknown, so this term covers night sweats that strike even though doctors don't understand why. "Distinguishing a cause can be tricky," Dr. Lillo says.

When To See a Doctor About Night Sweats

If your night sweats occur only a few times and then clear up, they may have been caused by a passing infection or lifestyle habit. But if they continue and disrupt your sleep, it's a good idea to check in with your doctor.

To figure out the cause, your doctor will likely inquire about your age and if you've entered menopause, your family medical history, if you have any lifestyle habits that put you at risk factors for cancer or other conditions, and about medications you take. They may do a routine exam to see if you have a fever or other symptoms of infectious disease or order further testing.

Share details as many details about your night sweats as you can, including their frequency and severity, Dr. Trovato says. "You should mention any medications you may be taking, any other known chronic medical issues, possible infectious exposures, and other associated symptoms," she adds.

Some particular symptoms of note, according to Dr. Ascher, include a fever, unintentional loss of weight, extreme fatigue, or swollen lymph nodes.

"A doctor can, and should, address the symptom regardless if the underlying cause is harmful (like cancer) or benign (such as menopause)," Dr. Lillo points out.

Treatment Options for Night Sweats

In order to treat night sweats, you'll have to pin down the cause and then respond accordingly. "For example, if a medication is causing excessive sweating that is not tolerable, your physician may consider switching to an alternative medication," Dr. Trovato says.

While you're investigating the cause, there are a few things you can do to ease the discomfort and get a good night's sleep. For one thing, make your sleep environment more comfortable: wear loose-fitting, lightweight, and breathable fabrics at night and keep the bedroom cool. Also, use layered bedding, so you can easily add or remove layers as needed, as Dr. Ascher recommends.

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