5. Your blood sugar is low
Normally, your blood sugar should be between 70 and 100 milligrams per deciliter, if measured when fasting. But if it drops below that 70 mark, whether because of diabetes or something like strenuous exercise, you may start to feel the effects. One symptom can be excessive sweating, or cold, clammy skin, particularly at the back of your neck at your hairline. (Watch out for a quickened heartbeat, shakiness, slight nausea, dizziness, and blurred vision, too.) Luckily, in cases of a mild dip, you can bring your blood sugar back up to normal by eating or drinking something. But if your blood sugar continues to drop, you'll likely start to notice other more serious symptoms and could require medical care.
More from Prevention: So You Sweat...A Lot. Here's Help.
6. You're eating the wrong foods
If you've been cursed with particularly fishy smelling B.O., you may have a rare genetic disorder called trimethylaminuria, which means your body can't break down the chemical compound trimethylamine, produced during digestion of foods like eggs, legumes, and fish. Instead, your body sheds excess trimethylamine via sweat, urine, and breath—often producing a smell not unlike rotting fish, rotting eggs, or garbage, according to the National Institutes of Health. If you think you may have trimethylanminuria, work with your doctor to come up with the best treatment plan, which will likely involve avoiding these foods and possibly popping certain supplements.
7. You might need more to drink than your workout buddy on your next long run
Ever had sweat drip into your eyes, only to find yourself in searing, stinging pain? Does dried sweat leave a gritty feeling or white streaks on your cheeks, too? You're probably a salty sweater, common among people who get lots of water during the day and keep sodium pretty low in their diet. You'll probably want to reach for a sports drink or an electrolyte tablet you can dissolve in some H2O sooner than the average exerciser. (Bored with plain water? Try these slimming Sassy Water recipes.)
8. You could have hyperhidrosis
If a doc can't find an explanation for your excessive sweating, you may have a condition called primary focal hyperhidrosis, when excessive sweating is a medical condition in and of itself. And no, spinning enthusiast, you do not have hyperhidrosis if you can produce a lake of sweat under your bike. Primary focal hyperhidrosis is typically marked by sweating so excessive it interferes with your daily activities.
"You're supposed to sweat when you're physically hot, or exercising, or stressed," says Pariser, who's also secretary and founding member of the International Hyperhidrosis Society. "People with primary hyperhidrosis sweat at times when they shouldn't." Even in a cool room, sitting perfectly still, a person with hyperhidrosis could have sweat dripping from her hands, he says.
Experts aren't entirely sure why it happens, but they do know that hyperhidrosis runs in families and is the result of too much stimulation from the nerves that trigger the sweat glands.
"The switch is stuck in the 'on' position," Pariser says. Depending on the location of the sweating, hyperhidrosis treatment varies, but can include prescription-strength antiperspirant (even on the hands and feet), Botox injections, and surgery.
More: Why Do You Sweat?
9. You could have lymphoma
Hyperhidrosis can also be a side effect of a number of health conditions—including gout, hyperthyroidism, and Parkinson's disease—and even some medications. Particularly troubling is that it can be a symptom of lymphoma, or cancer of the lymph cells, which play a role in the immune system. It's not completely understood yet why lymphoma can cause drenching sweat; it could be something about lymphoma itself or how the body responds to it, Pariser says. Perhaps it's a reaction to another symptom—fever—as the body tries to cool itself down. (Both fever and sweating are known as "B" symptoms and linked with more aggressive lymphoma.) Or, it could be caused by hormones and proteins produced by cancer cells themselves, according to the UK Lymphoma Association.
More from Prevention: 10 Cancer Symptoms Most People Ignore
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