14. Pimples on Your Chest and Back
Cotton fabrics sop up sweat and keep it close to your skin. Because acne-causing bacteria thrives in moist places, wearing cotton clothes to the gym can turn your skin into a breeding ground for pimples.
Wear moisture-wicking fabrics (like a polyester-spandex blend and microfiber) when you work out. Because they whisk sweat away from the skin, you’ll be less likely to break out (especially if you lounge in your gym clothes all day).