TRUTH: Sweat itself is essentially odorless. The source of any smell is the bacteria that cover our bodies: They break down proteins and lipids in the moisture from apocrine glands, the kind found in your armpits—and boom.
TRUTH: "Sweat is clear," says Jeannette Graf, an assistant clinical professor of dermatology at Mount Sinai Medical Center in New York City. "But when it combines with bacteria, fats, and oils on the skin, it can impart a yellow color to fabric." Many fabrics are vulnerable to discoloration, but dark colors hide stains better.
TRUTH: Toxins in the body are broken down by the liver and excreted in urine. But if you find saunas relaxing, then bake away—just be aware that all you're sweating out is water, salt, protein, and nontoxic urea.
TRUTH: If only. Anything you shed by sweating is water weight. "The next time you drink a glass of water, that weight will all be back," says David M. Pariser, a professor of dermatology at Eastern Virginia Medical School in Norfolk.
TRUTH: Remember that email forward that claimed the aluminum in antiperspirants is a health menace? "Large studies in major, reputable journals don't support such a connection, and we believe antiperspirants to be safe," says Ranella Hirsch, a dermatologist in Boston.
TRUTH: A higher rate of activity can make you sweat more, but the temperature of the room, your clothes, and your physical condition are all factors. "You can do a workout you've done before, and if you're in better shape, you may sweat less," says Dee Anna Glaser, a professor of dermatology at St. Louis University. Heart rate and calories burned are probably better indicators of effort.
TRUTH: On the contrary, it's harmless—and may, in fact, be appreciated. Dabbing antiperspirant under your arms curbs sweat there, but your body will vent heat in other locations. Wear moisture-wicking synthetic fabrics that pull sweat from the skin and allow it to evaporate.
TRUTH: Acne happens when sebum glands become clogged with oil, not sweat. The exception is bacne: A damp sports bra worn too long can push bacteria into the sebum glands, causing zits.
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Sweat: As if it weren't enough of a bother on its own, it's so misunderstood. Here, common misconceptions about perspiration that you can take with a grain of salt.
Check out the slideshow above to find out the truth about sweat.