Choose one that has more structure than those that lie flat against your mouth. But Dr Favini cautions that the more breathable a mask is, the less protection it may offer to the people around you. “There’s the tension of wanting people to have masks that are more comfortable versus wanting them to have ones that are more effective.” So if you're going to be indoors and/or around others, wear a more effective mask, even if it makes you feel hotter. (Or layer up. Which brings us to...)