Bringing exercise research in from the cold

Exploring the effects of cold-weather exercise

Nicole Graham - 31 January 2017

"Why am I doing this?"

That is the prevailing thought every time most of us don our toques and buffs to head out for some cold weather exercise. Running and other outdoor winter activities such as cross-country skiing can be hard to navigate in Canada's winter months-especially during a cold snap.

Is it safe to run in the extreme cold? What impact does cold-weather exercise have on my health? If you were to do a quick web search, you would find shockingly very little evidence-based guidelines for exercising in cold weather. For this reason, Faculty of Physical Education and Recreation associate professor Michael Kennedy was motivated to investigate effects of cold-weather exercising-namely on lung and respiratory function-with an overall goal of influencing policy.

"With our climate here in Canada and the number of elite and recreational athletes in our communities who train and compete in cold weather, it behooves us to take a closer look at the impacts these conditions have on our health."

Testing the conditions

One of the questions Kennedy has long pondered is, at what temperature does exercise-especially high intensity exercise-become unsafe for your lungs?

To explore this question, Kennedy took his research to the University of Innsbruck in Austria where he spent four months working on the research project.

Michael and his team tested seventeen active females between the ages of 18 and 30 who were used to intense exercise. These research participants completed running trials in random order at the following temperatures: 0, -5, -10, -15 and -20 C (40 per cent humidity). The tests took place in an environmental chamber that housed a treadmill and could operate in sub-zero temperature. Lung function was tested pre and post exercise, while distance, heart rate and perceived exertion were measured during the trial to ensure the participants were exercising at maximal intensity.

More than half of the participants started to experience respiratory distress around the -15 C mark. This distress was more significant in participants who were exercising at high rates of exertion. Interestingly, the participants who were elite Nordic skiers had a more vigorous respiratory response than the recreational athletes, meaning their reaction to the tests were the most severe.

"These results showed quite clearly that heavy intensity physical activity between the temperatures of -15 C and -20 C significantly influenced respiratory symptoms. During the test, based on the results of the measurements, the participants were showing signs of respiratory medical conditions such as exercise-induced asthma and bronchoconstriction."

And although the long-term risk to constant cold-weather exercise is chronic respiratory symptoms and exercise-induced asthma, Kennedy says participants' symptoms were fairly short-lived post-exercise and were completely gone after 30 minutes of rest.

Taking a proactive approach

Knowing the effects of cold weather exercise is only half the battle.

To help prevent symptoms like "runners" cough, wheezing and dry throat, Kennedy recommends elite and recreational athletes alike should cover their mouths with a Buff. The high-quality, polyester microfibre of Buffs provides high breathability and helps with warming air before taking it in, reducing the stress on the lungs to do the warming of the air.

Kennedy also recommends decreasing the intensity of exercise in temperatures colder than -15 C. For example, for those training for a marathon that is taking place in a warmer climate, consider taking it indoors when temperatures dips.

However, for cross-country skiing athletes, Kennedy says gauge your intensity levels and delay your return to a warm environment post exertion.

"Although it sounds counterintuitive, going inside immediately after a cold weather workout causes more stress on the lung because the already-stressed airways have to work harder to humidify the air at a warmer temperature. Take an easy warm down for five to 10 minutes until your breathing returns to resting levels before you head indoors. You will certainly cough less and your lungs won't feel like they are burning as much."

Next steps for Kennedy involve working with colleagues from the University of British Columbia and University of Innsbruck to put forth a case to have guidelines in place for amount of time, exertion levels and temperature for cold-weather exercise and training.

"Prolonged exposure to the elements that cause acute respiratory distress can evolve into a chronic condition as an athlete gets older. It's very important that guidelines are in place to help prevent potential life-long lung complications, especially with youth and young active adults who live in cold-weather climates."

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