Frigid Fitness: What To Know Before Embracing A Cold-Weather Workout

Prepare smart before you head out on a cold-weather run.The wind is howling, it’s cold outside, and you want to go for a run. As long as you bundle up, you should be OK, right? Not always, say exercise physiologists and cardiologists who study cold-weather exercise.

Exercising in extremely cold temperatures (less than 10 degrees Fahrenheit) can wreak havoc on your body and lead to serious complications, including permanent damage to the lining of your lungs. In fact, studies have found that up to 50 percent of athletes who typically train in cold weather— such as skiers and elite runners—have exercise-induced asthma, says Matthew Martinez, M.D., Medical Director of the Sports Cardiology Program at Lehigh Valley Health Network and chair of the American Council on Cardiology’s Sports and Exercise Cardiology Section.

Here’s how it works: When you breathe in very cold air, the airways leading to your lungs contract, making it harder to get enough air, a phenomenon known as bronchial constriction. Bronchial constriction can cause coughing, wheezing, and, over time, can even create permanent remodeling of your airways that are no longer able to contract and dilate normally.

To make matters worse, when you can’t get enough air, your heart has to work harder to get enough oxygen to your muscles to keep you moving forward. That raises not just your heart rate but your blood pressure too, says Martinez.

Fortunately, you don’t have to forego cold weather exercise, as long as you take some precautions. Follow these expert tips to stay safe and train smart.


According to a study in the journal Medicine & Science in Sports & Exercise, cold weather alters your sensation of thirst, so you may not realize you’re becoming dehydrated. Even mild dehydration can raise your heart rate and affect your performance. “Make sure you’re well-hydrated—pre, during and post-exercise,” says Martinez. “Your urine should be clear; by the time it becomes more yellow, you are already behind.”

Eat Carbs

People who exercise in cold weather might be more prone to hypoglycemia, or low blood sugar, says Lance Dalleck, PhD, an exercise physiologist at Western State University and a member of the American Council on Exercise’s Scientific Advisory Panel. That’s because your body doesn’t do a very good job of accessing fat stores during cold-weather exercise, relying instead on carbohydrates. Glycogen stores also deplete more rapidly in a cold environment, says Dalleck. A good rule of thumb: If your exercise session goes longer than 45 minutes to an hour, hydrate with a sports drink, and be sure to replenish with easy-to-digest carbohydrates post-exercise as well, says Dalleck.

Steer Clear Of Stress

Cold weather comes with its own challenges, which can be even more dangerous when they’re seemingly hidden. Watch out for heat stress, especially during snow sports. It might be 20 degrees outside, but the reflection of the sun off the snow can warm you up quickly. “While it seems paradoxical, you can get pretty pronounced heat stress in the cold,” says Dalleck. Signs you might be suffering from heat stress include muscle cramps, nausea, headache or dizziness. Ward off heat stress with layers, so you can peel one or two off as you warm up.

Layer Up—But Don’t Overdo It

A good rule of thumb is to dress as if it’s 10 to 20 degrees warmer than it actually is. So, if the thermometer says 40 degrees, dress as if you’re running in 50 to 55-degree weather. Your base layer should be made of a moisture-wicking material such as high-tech polyester that draws moisture away from your skin. Additional layers made from synthetic fabrics or lycra blends add warmth and insulation. Err on the side of more layers if you’re going for a slow jog and fewer if you’re planning a speed workout.

Know When To Head Indoors

If it’s very cold, move your workout indoors. At some point, exercising in the cold becomes dangerous—and counterproductive, says Dalleck. “Once you start getting below 5 or 10 degrees, the effort required to bring in enough oxygenated air creates a physiological strain that can actually hurt you. That’s when it’s time to bring your workout inside.” You can recreate the challenge of an outdoor workout by choosing the hill mode on a treadmill, increasing the incline slightly, or doing a quick interval workout.

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