The vast majority of the time, stinky feet are caused by one thing: Bacteria breaking down fatty acids in your sweat. Sounds innocent enough, but, as some of you know all too well, the biochemical process can create an odor powerful enough to clear a room when you slip off your shoes.
The bacteria on your feet is actually the same as what lives all over your body. So why are perspiring pads so much stinkier than, say, a sweaty forearm? You have more sweat glands on your feet—250,000 on each foot, in fact—which means more perspiration to turn into odor, explains Jane Andersen, DPM, communications committee chair for the American Podiatric Medical Association and podiatrist at InStride Chapel Hill Foot and Ankle in North Carolina. Plus, your feet are typically kept in an enclosed environment (socks, shoes), and less ventilation means more perspiration, she adds.
The exception: Your foul feet could be caused by Athlete’s foot, which is a fungal infection picked up in warm, moist places (like the locker room or around swimming pools) that creates its own odor, Anderson says. If your funk is accompanied by burning, itching, or stinging anywhere on your foot, head to your doc to confirm (it’s usually treated with a nonprescription cream).
If you have no other symptoms outside of a serious stench, you’re more likely just a victim of good ole body odor on overdrive.
But why can some guys go sans shoes without clearing a room? “Some people are just more prone to excessive sweating,” says Michael J. Trepal, DPM, professor of podiatric surgery at the New York College of Podiatric Medicine.
But you also might not be doing your feet any favors—especially if you’re guilty of any of these odor-inducing habits.