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Michael Bracko loves to work out in the cold. The Canadian exercise physiologist (and an American College of Sports Medicine fellow) loves the feeling of cold air on his face and the sound of snow crunching under his running shoes. In fact, he has no problem going for a run when it’s 30 degrees below zero. He did it just a couple weeks ago in Calgary, Canada.

“As far as the temperature goes, if you are just warm enough and you are used to exercising, there is no temperature you can’t work out in,” he says.

That is, as long as you’re properly dressed. Exercising in the cold does come with some potential dangers. Below freezing temperatures mean higher risk of hypothermia, so it’s important to cover the most vulnerable body parts, like the tips of fingers and toes, and your nose and ear lobes. In the cold, the body has to work harder to keep blood flowing to these appendages, since the smallest vessels in the extremities tend to constrict in order to keep blood in the body’s core for warmth. “Your fingers get so cold that they are so sore, red and swollen,” says Bracko. “The problem that can arise is that this can lead to a numbness, and the individual may not notice how cold they’re getting.

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What about frostbite? It’s actually unusual to develop frostbite while working out in the cold. That’s because you’re moving, and heating up the body; frostbite is more common when people who aren’t able to move are exposed to frigid temperatures and wind for extended periods of time. “When you exercise in the cold, the worst part is the first five to ten minutes. [After that,] suddenly you will get warm, and it’s no big deal,” says Bracko.

The only people who should be careful about continuing their outdoor exercise regimens in sub-zero temperatures are those with heart problems or asthma. Heart patients, and even people who suffer from angina, the chest pain that can indicate poor blood flow, can aggravate such blood flow problems in the cold. The same applies with people suffering from asthma, since the colder, drier air can irritate already sensitive airways. “Cold air in and of itself can cause exercise induced asthma,” says Bracko. “It’s really dehydrating and it can trigger an asthma attack.” Most exercise professionals recommend that people with health conditions stick to indoor activities when temperatures dip outside.

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But for the rest of us, they say that cold weather shouldn’t be a deterrent to exercising outdoors. Wearing layers, and including synthetic fabrics instead of cotton, can transfer any perspiration from one layer of clothing to the next, keeping you warm and dry. It’s possible to overheat even in freezing temperatures, however, so it’s important not to overdo it and dress too warmly. If you’re too warm, you’ll sweat more and your clothing may not be able to wick away all the perspiration you generate. If that happens, when you take a break, all that moisture will quickly become cold make you feel chilled.

And if you still need convincing that venturing into the cold is worth it, there’s this — our moods tend to dip in the winter months since the days are shorter and we spend more time indoors. Getting a blast of crisp air and being active can counteract the blues. As long as you exercise smart, there’s no reason outdoor activity can’t be a part of your fitness regime — even during a polar vortex.