You've probably heard that regular workouts can strengthen immunity, but even the cleanest gym can be an unexpected source of germs that can make you sick. Spending just a few seconds disinfecting equipment before you use it may help stave off the sniffles (more than half of cold and flu viruses are caught by touching your eyes or nose after handling a contaminated area). "Who knows how many people have held onto that treadmill rail before you--or what germs were on their hands," says Kelly Reynolds, Ph.D., an associate professor at the College of Public Health at the University of Arizona in Tucson. Don't rely on your gym's bottle of disinfectant solution. Like a pen in a doctor's office, the outside of the bottle can be riddled with germs. Instead, stow some disinfecting wipes in your gym bag. Use one wipe for each piece of equipment, and make sure you rub down the buttons and handles. Don't forget yoga mats and free weights--they're just as likely as cardio machines to carry bugs. And try to avoid rubbing your face until you can wash your hands after your workout.