14 Potential Causes of Night Sweats, Plus What to Do About Them
Have you ever gotten really sweaty as you sleep? If so, you’re not alone. Experiencing mid-slumber sweating, something many people refer to as “night sweats,” is pretty common, says Elizabeth R. Roth, MD, internist at Massachusetts General Hospital and assistant professor of medicine at Harvard Medical School.
“People bring [the issue of night sweats] up quite a bit,” adds Leigh Simmons, MD, primary care physician at Massachusetts General Hospital and assistant professor of medicine at Harvard Medical School. In fact, a 2002 study of primary care practices found that 41 percent of patients reported experiencing night sweats, defined as "sweating at night even when it isn't excessively hot in your bedroom,” during the last month.
But just because night sweats are common doesn’t mean they should be ignored. Aside from disrupting your sleep and drenching your sheets, night sweats can sometimes signal a more serious underlying cause.
Here, with the help of three doctors, we explain night sweats, what may be triggering them, why it’s important to always brief your physician on the issue, and the treatment options that can bring you better, cooler slumber.
What, exactly, are night sweats?
Though all three doctors interviewed for this article say night sweats are a fairly common issue raised by patients, what people think of as “night sweats” doesn’t always constitute the textbook definition.
Night sweats, by medical definition, are episodes of extreme overheating at night that cause your body to perspire so much that you need to change your clothes and/or bedsheets, says Simmons. These sweats aren’t caused by environmental factors—like sleeping under too many blankets, or sleeping in a steamy room—but rather, are driven by an underlying, internal cause.
Feeling hot or somewhat sweaty at night, though undoubtedly uncomfortable, doesn’t constitute a night sweat. “Generally when people complain of night sweats, it's generally not truly that definition,” says Amber Tully, MD, family medicine physician at the Cleveland Clinic. Determining the severity of your mid-slumber sweating is an important clue that can help your doctor determine a potential cause.
“Usually, we are not concerned about a worrisome underlying cause, unless it's reached that level of the severity where they're having to change their own clothes, or change sheets,” says Simmons.
What causes night sweats?
Knowing whether or not you have night sweats, per the above definition, is pretty straightforward. Pinpointing the cause of your night sweats can be much more difficult.
That’s because there are many potential causes for night sweats and the reason behind them “runs the gamut from bothersome but benign to quite concerning,” says Roth. Night sweats that are bothersome, though not dangerous, are more common than night sweats with a more concerning underlying cause, she says. In fact, the “majority of the cases end up being benign,” says Tully. With that in mind, here are some potential causes of night sweats. Note this list is not exhaustive:
- Perimenopause and menopause - The hormonal changes that women experience during these mid-life phases can cause extreme hot flashes, both during the day and at night.
- Antidepressants - Certain antidepressants may cause night sweats, says Simmons, and this type of medication is one of the most common causes of night sweats, adds Tully.
- Lymphoma - About a quarter of patients with this cancer of the lymphatic system experience night sweats, says Simmons.
- Human immunodeficiency virus (HIV) - Night sweats are a “very, very common” symptom of this immune system-attacking virus, says Simmons.
- Tuberculosis - This infectious disease, which primarily affects the lungs, has been known to cause night sweats.
- Thyroid disease and disorders - Dysfunction of the thyroid, a small gland that produces a specific type of hormone, could cause night sweats.
- Specific infections - Certain infections, like those of the heart valve or the bones, could trigger night sweats, says Simmons.
- Hormonal medications - Many medications have night sweats listed as a side effect, says Simmons, and in certain cases, stopping a medication could trigger a bout of night sweats. “Sometimes it's hard to figure out if the medication is the cause of [the night sweats], or if some other illness they’re being treated for with the medication is the cause,” caveats Simmons. “But, certainly there are many medications that have been implicated as a cause of night sweats.” One category of medication linked with night sweats is those that induce a low-hormone state, like medications to treat prostate cancer, breast cancer, or endometriosis, says Simmons. Medications that increase hormones could also be linked to night sweats, adds Tully, like certain types of birth control and hormone replacement medications.
- Over-the-counter medications - Any med that lowers your body temperature, like regular Tylenol or Tylenol PM, could induce sweating, says Tully. So if you take these medications before bed, that sweating could happen mid-slumber.
- Blood pressure medications - Certain blood pressure medications that widen your blood vessels can cause nighttime sweating, says Tully.
- Erectile dysfunction medications - This class of meds may cause flushing and sweating, says Tully.
- Excess insulin - Diabetic patients who over-treat their diabetes and take too much insulin before bed may experience low blood sugar in the middle of the night, says Tully. If these levels are low enough, your body may sweat in response.
- Anxiety - When you’re anxious, your body typically releases a hormone called cortisol. Excess levels of cortisol could lead to night sweats, explains Tully.
- Alcohol consumption - Drinking alcohol before bed may cause your blood vessels to widen, which could then lead to mid-sleep sweating, explains Tully.
How can you determine what’s causing your night sweats?
If you’re regularly waking up sweaty, you should first make sure that an environmental factor—like too many blankets or an extra-hot bedroom—isn’t to blame, says Tully.
If you’ve ruled those factors out, you should definitely bring up the issue with your doctor rather than ignoring it or trying to determine the underlying cause by yourself. “It wouldn't be something I'd recommend Googling or trying to figure out your own because there are so many different things that could be contributing,” says Tully.
Once your doctor is looped in, they will likely analyze your medical history, taking into account, for instance, if you are a woman in the age range for menopause, if you take any medications, and/or if you are experiencing other symptoms, like weight loss, daytime fevers or decreased energy, which could be a sign of more serious illness. If needed, they may order blood work or other tests to confirm or rule out the more serious causes.
That said, “usually, we don't figure out what caused the night sweats,” says Simmons, which she says is “okay, as long as you rule out the dangerous things.” In those unsolved cases, the night sweats may go away on their own, or the sweaty sleeper will try different options for managing them, says Simmons, like lowering the temperature in the bedroom or buying breathable sheets.
If you find yourself experiencing night sweats, Simmons suggests taking note of any things that seem to make them better or worse, or other associations, like taking certain medications or drinking alcohol before bed, for example. “Those are the kind of clues that your doctor will find very helpful, and even if you don't know the cause right now, you've at least got documentation,” she says.
What can you do about your night sweats?
As mentioned, you should always see your doctor if you are experiencing persistent night sweats, rather than trying to treat them on your own. Once you’re at the doctor, treating night sweats is typically focused on treating the underlying cause rather than on the night sweats themselves.
If your doctor is in the process of determining the underlying cause of your night sweats and/or they were unable to pinpoint a cause, you can alleviate the discomfort of night sweats by wearing layers to bed, considering bedsheets with breathable fabrics, setting up a fan in your bedroom, using air conditioning, and opening windows, says Roth.
Lastly, though night sweats can be confusing and uncomfortable, “don’t feel like there’s nothing that can be done,” says Roth. As mentioned, It’s important to bring up your night sweats to your doctor so they can determine if there is a more serious issue that needs treatment, says Roth. They can also help you figure out solutions for more comfortable sleep.