The Truth About Your Night Sweats

If you wake up drenched in sweat, think of your armpits as evidence. You’ll have to do some sleuthing to figure out what’s prompting your perspiration.

Night sweats aren’t rare: In one study published in Annals of Family Medicine, about one-third of primary care patients reported night sweats during the past month.

However, no one knows exactly how common the condition is, because most sufferers of night sweats never report the symptom to their doctor, says study author James Mold, M.D., a professor of family medicine at the University of Oklahoma.

In a literature review published in the Journal of the American Board of Family Medicine, Dr. Mold and his colleagues revealed that several factors increase the likelihood of night sweats, including panic attacks, sleep problems, fever, numbness in hands and feet, anxiety and stress, and trouble breathing at night.

Night sweats may also be a side effect of medication, including selective serotonin reuptake inhibitors (SSRIs), commonly prescribed for depression. “Though causation has neither been proven nor disproven with certainty, it seems likely that SSRIs are a cause,” says Dr. Mold.

The worst case: Night sweats could indicate a serious problem. Dr. Mold’s study review suggests that they can be a symptom of autoimmune diseases, heart problems, endocrine disorders, gastroesophageal reflux disease, HIV, tuberculosis, certain types of cancer, sleep apnea, and panic disorders.

How can these things make you soak through your shirt? Your body uses sweat to reduce your core temperature when it spikes above a threshold called the thermoneutral zone, research suggests.

Lots of things push your body temp into this zone, from use of heavy blankets to inflammatory processes inside your body when you have an infection or disease.

Some research into night sweats even suggests that these inflammatory mediators periodically spike during the night.

What’s more, several other conditions can impact your sympathetic nervous system, your sweat glands, or other factors that influence your body’s ability to regulate its temperature, research shows.

Another theory about night sweats might apply to healthy guys: People who work out may be conditioned to sweat at lower temperatures than expected, Dr. Mold and his colleagues posited in their study review. It’s not clear whether this could lead to night sweats, but one study in Human Kinetics did find that night sweats can be a sign of overtraining.

(Your perspiration can be more telling than you think. Discover What You Can Learn from Your Sweat.)

The bottom line: If you wake up in a pool of sweat almost every night, or if your alarm sounds and you’re soaked through your pajamas, you should see your doctor, says Dr. Mold.

He also suggests monitoring your body temperature twice a day for a week to detect any fevers, and keeping a record of other symptoms to bring to your doc. Usually, night sweats aren’t the only symptom when something is wrong.

The best strategy to reduce night sweats is to treat whatever underlying condition is causing them. In the case of SSRI-induced night sweats, some people have seen improvement by adding medications called alpha-adrenergic blockers, research shows.