How cold is too cold for an outdoor workout, and just how dangerous is shoveling for your heart?

For some people, the thought of braving temperatures in the teens and twenties seems dangerous, but is it? Even on frigid days, runners and cyclists may be out on area roads and bike paths, making sure they get in a workout. For some people, the thought of braving temperatures in the teens and twenties seems dangerous, but is it? When coming back inside from a workout, Barberio said it’s best to let your body reacclimate to indoor temperatures before jumping into a hot shower. Severe cold, shoveling and heart attacksShoveling snow is a physical activity that Barberio and Dr. Brian Choi, professor of medicine at George Washington University, said can increase the risk of a heart attack.