You know the rules: apply an SPF of at least 30 every two hours. But here’s an unknown fact for you: when you’re working out, you need to apply it even more often. Sweating dilutes the effectiveness of sunscreens. So on a run or yoga class extending an hour, pack the SPF. We recommend a stick, such as MD Solar Sciences Mineral Sunscreen Stick Broad Spectrum SPF 40 ($18, sephora.com), that’s easily portable.
And if you can, opt for water-resistant, because “[these] sunscreens maintain effectiveness for a longer period of time,” says Robert J. Friedman, MD. “The FDA recognizes water resistance for 40 or 80 minutes. Regardless, reapplication is recommended.” Because chemical-based sunscreens are only effective 15-30 minutes after application, Friedman recommends using a physical/mineral based formula that requires no downtime.
If reapplication isn’t in the cards, shade the skin most susceptible to burn (your nose, forehead and scalp) by wearing a hat when exercising outdoors. The brim also prevents sweat at the forehead from dripping down the face and diluting the SPF. Double the protection with a hat that has ultraviolet protection factor (UPF).
Read more: You’re Doing It Wrong: Self Tanner