Blue sky so clear, the sun shining so brightly and blinding as it reflects off the white snow. The crunch of crisp snow under my feet while soaking up vitamin D through the one inch of exposed skin on my face. This is running in sub-zero temperatures and a great way to spend a Sunday morning. OK, truth fully, this isn’t how I spend most Sunday mornings anymore but there was a time. I remember one such time returning from a long run; carrying what felt like an extra 20 pounds of sweat and frost-soaked clothing and hurting everywhere. I believe I said something to my running buddy like “this must be what arthritis feels like”. Now that I am older, I can confirm that some days it doesn’t feel much different. After the run I remember limping to my vehicle and spending much of the day recovering, which for me as an asthmatic, also included coughing.
So, the question I ask myself if it’s safe to run in the cold? Growing up in the northern hemisphere, I know that I am not likely to freeze my lungs by doing activities in the cold weather. I grew up in Fort McMurray and honestly don’t remember too many days that we weren’t allowed out to play at recess, but I do remember a number of days below -20 degrees Celsius. It is also fairly wide spread knowledge that you need to dress appropriately for outdoor activities (layers are best with a synthetic material next to your skin to whisk the moisture away), always wear a hat to prevent loss of body heat through your head and if it’s too cold, hit the treadmill or take a rest day. But what risk is there to your lungs by doing exercise in the extreme cold? Why do I cough more in the wintertime after a run than I do any other time of the year?
The answer to this question lies in the air. Our bodies are amazing machines that are designed to keep us safe and decrease risks from things such cold air. The main reason why your lungs won’t freeze when breathing in cold air is due to a thin layer of liquid that lines our airways that helps to warm and moisten the air before it reaches our lungs. However, as air temperature decreases it also decreases in water content. One of the other things that most people in northern Alberta know is that when the air gets cold, everything dries up; out comes the humidifiers and body cream.
When at rest or during light exercise most people breath through their nose, so by the time the air reaches their lungs it is both warmed and saturated due to the regular functions of our bodies. However, as you work harder, we tend to breathe through our mouths instead of our noses, or a combination of both. We also breathe faster in order to get more air to our lungs and muscles to help keep us moving. This increase breathing frequency, in combination with breathing through our mouths, means that the air reaching our lungs is not as warm or moist as our bodies would like. The cold, dry air causes irritation to the lungs which results in something called bronchoconstriction. This is a narrowing of the air passages in your lungs. Your body’s automatic response will be to cough, to try and get rid of air that is stuck in the lungs and make room for new fresh air. This is a symptom of breathing the cold air and not a cause of lung disease. If you have any issues with your lungs such as asthma, the response to the cold air may result in an increased response to this bronchoconstriction or take longer to recover from the body’s response to the cold air.
As with any training, the more you do it, the easier it will become. This applies to cold weather training as well. The more you run outside in the winter, the easier it will become. You can train or acclimatize your lungs by starting off easy (shorter and slower runs) and gradually making each run more difficult. In addition, concentrate on your breathing and try not to force air in and out of your lungs. Finally, try wearing a moisture-wicking neck warmer over your mouth and nose as this helps to warm the air and traps moisture as your exhale.
My days of long winter runs in sub-zero temperatures are likely over. Not because of incessant coughing more because I finally realized running 40 km wasn’t really that much fun for me anymore. But hey, if it’s your thing, go for it and know that your lungs are safe.
Koskela, H. International journal of circumpolar health: 2007 April; 66(2)91-100