A Mile-by-Mile Analysis of Running in Subfreezing Temps

Jason Saltmarsh
by Jason Saltmarsh
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A Mile-by-Mile Analysis of Running in Subfreezing Temps

You can run outside all winter long. Really, you can. Of course, you could stay indoors and find a treadmill and a good movie on Netflix, but that’s probably not why you fell in love with running in the first place. You want to run free and be out there exploring new trails and feeling the weather on your face as you nail another epic run — even if it’s a subzero run…

Here’s a mile-by-mile breakdown of how cold weather affects your 5K run and why you feel the way you do when the thermometer drops below 32°F. Understanding why you feel the way you do will help you run better — and worry less — the next time you go for a run.


This is the worst part. It’s like trying to start a car on a cold day. Your body is going to reject the sudden change in aerobic effort with a racing heart. Your muscles and joints are going to scream at you while they slowly warm up. And the cold air will make it hard to breathe. It might even make your teeth hurt. Don’t worry, stick with it, it gets better.

You may wonder how we can breathe such cold air without damaging our lungs. Cold air enters your mouth at freezing temperatures, but heats up and humidifies before filling your lungs. The burning sensation some people feel when breathing in cold air usually goes away after a few breaths and is attributed to the dryness of the air, not the frigid temperature.

Keep going…


At this point, runners usually complain of cold fingers and toes. Your cheeks may burn, and your eyes may tear up in response to the cold wind. This is the point in your run where you think about all the good things about running and how lucky you are to be healthy enough to enjoy it.

Cold fingers and toes are a survival response. Your body notices the drop in temperature and heats your core at the cost of your extremities. Keeping your body warm will help keep your hands and feet warm. Your eyes produce tears to stay hydrated while being subjected to cold, dry air. Sunglasses can help reduce tearing.

Keep going…


By mile three, most runners are feeling comfortable and beginning to sweat under their multiple layers of winter gear. If you overdress, you’ll be uncomfortably hot by now. A good rule of thumb is to add 20°F to the temperature outside, and dress as you would if you were going for a walk. Your internal furnace is linked to how hard you push yourself and your level of cardiovascular fitness. More advanced runners can often wear less and still feel warm, compared with newer runners who may need extra layers.

Run within your capabilities, and don’t go so far that you can’t make it home again. Getting stranded and walking home on frigid days after you’re wet and sweaty is a recipe for hypothermia. Winter running is beautiful and invigorating, but it deserves your respect and full attention.

About the Author

Jason Saltmarsh
Jason Saltmarsh

Jason is a competitive masters runner and freelance writer who covers sports, fitness and healthy living topics for several national magazines and websites.


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