While a "polar vortex" doesn't necessarily sound like an occasion to dress up, fashionistas everywhere are embracing the layered look, using the cold as an excuse to pile on fabulous furs, knits, and cashmere all at once. Sure, street style is easy in the icy weather, but when it comes to winter workout gear, it gets a little trickier. Whether you're finally trying to reach your "get healthy" resolution or are already a seasoned fitness fanatic, don't let the frigid air throw you off the running path. From stylish sweats to designer accessories, check out the 10 pieces you should add to your workout wardrobe.