Choose earmuffs that fit snugly and don’t flop around as you run. Behind-the-head earmuffs are great since they’ll keep the back of your head warm, too. Pick a pair with breathable fabric that wicks away moisture so your earmuffs don’t get sweat-logged. The earmuffs should provide warmth, but you shouldn’t really notice that you’re wearing them at all. They should also allow you to hear your surroundings.