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Cold-weather exercise hard on the lungs

Amy Kenny
Crystal Schick/Yukon News file Runners in the Yukon Arctic Ultra marathon race down the Yukon River near the Marwell industrial area in Whitehorse on Feb. 3, 2019.

Amy Kenny

Special to the Yukon News

It might make you feel pretty tough to go for a run or a ski when it’s -35 C, but according to Dr. Michael Kennedy, it’s also tough on your lungs.

Kennedy, an associate professor with the faculty of kinesiology, sport and recreation at the University of Alberta, has spent the last few years studying the impact of cold weather sports on the lungs of athletes.

He likens the experience to scratching your forearm—the faster you scratch, the more irritated your skin gets. The same is true of your lungs in colder weather. The faster you’re moving and breathing in temperatures of (for the purposes of his studies) -15 C and colder, the more irritated your lungs get.

“You’re scratching your lungs on a cellular level,” Kennedy says over the phone from Edmonton.

On some level, we’ve all experienced it.

“In the Yukon, you maybe go outside and go get groceries, you aren’t covering your mouth and it’s -25 C outside and inside [the store], it’s +20 C, that can trigger some symptoms like cough,” says Kennedy.

It starts to become a more serious issue when done consistently and vigorously.

In 2019, Kennedy published a study in Respiratory Physiology & Neurobiology. During the course of the study he followed 16 men and women (who reportedly were regular cold-weather exercisers) as they completed a five-kilometre run in -15 C.

All 16 participants reported some sort of respiratory difficulty after the run, with more than half showing airway constriction on a level that would be consistent with someone who experiences exercise-induce asthma.

Arctic Ultra athletes battle -30 temperatures and colder as they attempt to race from Whitehorse north along the Yukon River on Feb. 1, 2018. (Crystal Schick/Yukon News file)

In another study looking at elite women cross-country skiers, he found similar results. Kennedy had participants complete the Leicester Cough Questionnaire (used in clinical studies as the “gold standard of cough questionnaires,” he says) and a recovery-stress questionnaire three separate times during the course of a year. There was little change early in the season, but during the winter months, Kennedy saw an increase in sputum eosinophils, one of the cardinal features of asthma.

“It was just to give us a sense of whether a super fit cross country skier would have the same score as a severe asthmatic with COPD and heart failure,” he says. “Ironically, they do. That’s interesting.”

Kennedy says he thinks that, to some degree, there’s a normalization among cross-country skiers and some biathletes, of chronic respiratory syndrome, but he says it can have greater consequences than just an annoying cough.

Some of the elite Canadian skiers he’s worked with have reported loss of sleep (and waking up feeling exhausted) due to coughing, as well as a general sense of being distressed.

Though he says northerners may have a different threshold than the -15 C he’s studied in the south, he says there are some things cold-weather athletes everywhere can do to mitigate potential damage.

Wearing a buff, wool scarf, or face mask can help. Not only does it allow some space for the air to be heated before it’s inhaled, a mask or scarf will usually gather moisture, which pre-humidifies the air before it’s inhaled. Both of these are important, as two of the three key factors affecting the lungs are cold conditions and dry conditions. Both cause the airway to constrict. In the case of cold, the lungs can also have an inflammatory response.

The third factor is shear stress; the flow rate of air coming into the lungs. To combat that, Kennedy says slowing your stride can help.

“If you’re talking, you’re breathing 10 litres of air per minute,” he says. “Running, you’re running at five to 10-fold that rate … slow down. If you’re used to running a five-minute kilometre and it’s super cold out, slow down.

“And if it’s really, really cold, take it inside,” he says. “Your lungs are going to thank you.”

Going forward, Kennedy is hoping to study skiers at the Canadian cross-country ski nationals to see how their lungs respond over five days of competition. The study has been approved for athletes down to 14, which Kennedy says is exciting in terms of prevention and understanding whether there’s a point in an athlete’s career at which things get worse.

He also has an online survey looking at the factors that impact lungs.

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