Cover any breaks in the skin. Normal, unbroken skin can't be invaded. But when a skin break—even one as minor as a small scratch or the raw skin characteristic of psoriasis— comes in contact with an infected surface, MRSA and other bacteria can worm their way in. The earliest danger signs: pimplelike red bumps or boils. To protect yourself, put a band-aid on any cuts, abrasions or blisters. And don't shave immediately before a workout to avoid being in the locker room with cuts and scratches.
Don't go barefoot. Along with the human traffic and the absence of sunlight in locker rooms, the heat in showers, saunas, hot tubs and steam rooms all conspire to create a perfect growing environment for germs. Wear flip-flops or water shoes to avoid athlete's foot, a fungus condition that usually starts with itchy scales and blisters between the toes (a blister counts as a skin break, another reason to protect your feet from the floor). Shoes will also keep you from slipping on wet tiles.
Use disinfectant.Clean exercise equipment before and after you use it, with paper towels and disinfectant or with disposable wipes. Do the same with communal yoga mats.
Change your towels and clothes. If you can, use a fresh towel provided by the club on each visit. If you'll be bringing your own, be sure to bring a new one daily. A damp towel left in a locker or gym bag is a germ magnet. Besides, chances are your towel has hit the floor at some point. The same goes for socks and gym clothes. Wearing the same sweaty items over and over isn't just smelly, it's unhealthy. Wash everything in hot water and use the full dryer cycle.
Don't share. When it comes to goggles, sweatbands, razors, and towels, neither a borrower nor a lender be. Don't even share soap—use liquid soap rather than a communal bar.
Keep your towel on.It's best not to stride around in the buff. "Use your towel as a barrier between your skin and any shared surface, including benches," says Otis. Remember that even a tiny break in the skin could let in an infection.