Why Do I Sweat a Puddle Every Night?

Ah, friends. They're like family but cooler. Fully customizable. Fall and one of them will be right there to pick you back up. But as great as friends can be, they also do a lot of really stupid stuff. Stuff that blows your mind. Like, sometimes it seems crazy that you even hang out with people who make such crappy decisions. Stuff that, were it to get out, would be mortifying for anyone with even a shred of self-respect. Lucky for your friends, they've got you to ask their deepest, darkest questions for them. And lucky for you, we started this column to answer those most embarrassing of queries.

The sticky scenario: You've woken up from a night of sound sleep to find your pillow is drenched. Great, you think, the cat knocked over the water I set out before bed. But when you look over at the nightstand, your glass is still filled to the brim. Um, did all that liquid come out of…you?

The facts: If you find yourself waking up a little damp, you're not alone. Night sweats—or "nocturnal hyperhidrosis" if you want to get scientific about it—are actually pretty common. One study from the Journal of Family Practice found that 41 percent of people visiting their primary care physicians had experienced night sweats in the previous month.

What's the worst that could happen? Dermatologist Dee Anna Glaser, president of the International Hyperhidrosis Society and the interim chairman of the department of dermatology at the Saint Louis University School of Medicine says that one "classic" cause of night sweats is tuberculosis. "Tuberculosis is, of course, very contagious to those around you, and needs to be investigated—quickly—and treated," Glaser says.

TB isn't the only medical condition associated with nighttime sweating, however. It can also be a presenting sign of a plethora of cancers (hey, you asked for the worst news) including lymphomas, leukemia, and other hematologic disorders and blood-based cancers. Different cardiac and pulmonary diseases are associated with nighttime sweating, too, along with neurologic conditions like a stroke.

"I would say that night sweats should be taken seriously," Glaser adds. Are you sweating yet?

What's probably happening: Okay, now that we've properly freaked you out, here are a few less-scary-but-still-serious possibilities: Glaser says night sweats can be caused by something more manageable, such as a hormone disorder like hyperthyroidism, or diabetes, or even low blood sugar. Menopause, too, is a common reason for nocturnal hyperhidrosis, as is chronic pain syndrome.

Medication from aspirin to Viagra can also produce night sweats as a side effect, along with just about any anti-anxiety drug or antidepressant—up to 22 percent of people taking antidepressants have reported getting sweaty while taking their meds.  And have you considered turning down the thermostat? (No, seriously.) The first thing Glaser tries to determine when meeting a new patient is if the root of their excessive perspiration is physiological or environmental rather than medical—and you'd be surprised how many people are wearing pajamas that are too warm or huddling up under too many blankets. "If your spouse or partner loves the room at 80 degrees and you're used to sleeping at 60 degrees, you're probably going to be sweating at night," she says. In that case, the fix is a simple one: dressing light and investing in some good moisture-wicking sheets.

So, should you lose sleep over it? While there's probably no need to get all hot and bothered, Glaser recommends getting your clammy behind to a doctor if you're regularly waking up drenched or if this is something that's new to you—especially if you're experiencing other like fatigue, fever, chills, a cough, or just a general run-down feeling.

Also, try to keep track of where you're dampest, as sweaty pits can indicate a significantly different problem than sweat that's localized in the palms or the soles of the feet or all-over swampiness.