What about fitness levels? “You will lose whatever advantages you’ve gained over time and be back down to couch potato status within three to six months, but the effect of inactivity starts within days,” says exercise physiologist J.P. Hyatt, an associate professor in the Department of Human Science in the School of Nursing and Health Studies at Georgetown University. For starters, he points out that cardiopulmonary fitness can decrease by 20 percent within three to eight weeks of stopping your workouts.
For those who worry that being active outdoors in extreme cold also poses a risk to health, sports physiologist Mike Bracko of the Institute for Hockey Research in Calgary, Alberta, offers reassurance: “There is no real danger, whether you’re running, cross country skiing, taking a long trail walk or anything else, as long as you’re prepared and dressed appropriately.”
Delia Roberts, an exercise physiologist who chaired the winter-sport interest group for the American College of Sports Medicine, agrees. “As soon as you start exercising at a reasonably high level — even just walking with purpose — about 40 percent of the energy you consume is lost as heat, and so your body very quickly warms up” she explains.
The key is learning how to keep your overall body temperature at a constant level. “If you lose too much heat, that’s when it becomes problematic,” says Roberts, who says careful layering is key to guarding against the cold, wind, rain, snow and other elements. She suggests always protecting your extremities — head, hands and feet — which lose heat quickly, and using a vest to keep your core toasty.
Many people wonder whether there’s a specific danger temperature, but it’s really all relative. “Everybody’s different — one person may not want to go outside at 32 degrees, while another is okay at zero — so it’s really based on individual comfort level,” says Bracko, who exercises outdoors throughout the Canadian winter and finds it “refreshing and invigorating.”
Roberts says she knows people who are active outside no matter the weather, and she provides some tips that may allow you to do the same.