The cause can be as simple as a postnasal drip, brought on by the cold. Try pulling a neck warmer over your nose and mouth to warm the air before it hits your throat, squelching a cough. But if every chilly jog turns into a hack-fest, it's time to see a doctor. You might have exercise-induced asthma, a tightening and swelling of your airways that can be triggered when you breathe in cold, dry winter air. Other symptoms may include wheezing, tightness in the chest and shortness of breath within five to 30 minutes of your workout. "Many women have this condition but don't know it," says Rob Danoff, D.O., an osteopathic physician in Philadelphia. "They think they have a cold or they're out of shape and need to train harder." Your doctor may prescribe an inhaler to use 15 to 30 minutes before your run or another medication to alleviate symptoms.