As you sweat, your pores open up and allow dirt, oil and bacteria to be excreted. When you’ve got makeup blocking those pores, they can get all clogged up with whatever concealer, foundation or powder you’re wearing plus all that dirt, oil and bacteria. As you can imagine, this leads to nasty breakouts or stubborn blackheads. Make sure to throw a bag a pack of face-cleansing wipes in your gym bag.
MORE: Is Wearing Makeup At the Gym Bad for Your Skin?