running extreme cold

Can Running in Extreme Cold Permanently Hurt Your Lungs?

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By Corrine Malcolm,
CTS Ultrarunning Coach

You’re right, you’re not going to “freeze your lungs”… however, exercising and competing in extreme environmental conditions can have a long lasting negative impact on your lung health. Every winter runners flood my social media feed covered in various forms of human icicles, temperatures flash across the screen “0F” “-16F” “-36F”, wind chills dropping the skin temperature lower. Every winter I cringe and have to ask, “at what cost?” Is there a specific purpose to be gained, aside from “proving your own toughness”, by slogging out the miles as temperatures dip below zero?

Of course, you may live in a cold, wintery place. I myself grew up in Northern Wisconsin and routinely had school canceled growing up when the temperatures would dip, almost every February, to -35F. Growing up as a cross-country skier, winter and cold were an unavoidable part of my childhood. In college I studied exercise and environmental physiology and watched my teammates struggle with “skiers’ cough”, which for some turned into what we thought at the time was asthma. I began to wonder, what does happen to our lungs as we train and race over time? The answer is an increased risk for developing a hyper-reactive airway, or what is now called exercise induced bronchospasm (EIB), what was originally called exercised induced asthma.

Exercise Induced Bronchospasm

I like to think of EIB as an overuse injury of the lungs. The cells that line your lungs are incredible, and they have an amazing capacity to repair themselves quickly. However, this repeated injury-repair cycle is responsible for adaption and structural change that is not always positive. When you exercise your ventilation rate increases, and when combined with another variable like cold and/or dry air (note that the issue with extremely cold air is that it is extremely dry), you cause water to evaporate from the airway surface liquid that makes up the lining of your bronchioles at a rate your body cannot keep up with. This drying causes a shift in the osmotic gradient, or the movement of liquid, of the cells lining your airway, which stimulates the release of inflammatory mediators. These inflammatory mediators, like histamine, can influence the smooth muscles of the bronchioles, causing constriction, mucus build-up, and edema (swelling) (1).

bronchospasm

 

Now, this is a slow and progressive problem. One day of running in extreme cold does not guarantee a lifetime of breathing issues. However, continued training in extreme environments does heighten your risk. There are certainly factors that may predispose you for developing EIB, including; high intensity activities, history of asthma, allergies, a history of atopy (or being hyperallergric, and allergic rhinitis (an allergic reaction to airborne allergens) (5). Additionally, the environmental conditions you regularly train and race in are known risk factors, including cold air, dry air, high pollen counts, pollution, insecticides, fertilizers, wildfire smoke, chlorination, car exhaust, etc (5).

Risks Over Time

As I mentioned above, this airway inflammation and airway limitation appear to progressively worsen over a season and over a lifetime in many endurance athletes, with 90% of the asthmatic population and 20% of the general population reportedly developing EIB (1,2, 5). You might be thinking to yourself, so that one time run is probably okay, and honestly you might be right. However, what we gathered in the lab on skiers was that even after a single week of training or racing in single digit temperatures all of the skiers in the study suffered a varying decrease in measures of expiratory volume (amount of air you can forcefully exhale), which could translate to a decrease in performance.

That’s right, if not for your general health, do it for your performance. The demands we place on our pulmonary system as endurance athletes is immense, sometimes so much so that we exceed the capacity of that system. The repeated drying of your airway surfaces over time can cause a thickening of those membranes (2). This causes a reduction in our ability to combat the evaporation of the liquid surface of our airways (1) so that your airways become more sensitive to irritants over time. This makes EIB progressive in nature, and ultimately leads to a ventilatory limitation during performance as a result of those permanent airway-structure changes due to frequent environmental exposure (3,4).

Protecting Your Lungs

So what can you do to protect your lungs? As my yoga teacher told me this past fall as the Bay Area was inundated by smoke from forest fires just north of us, “It’s a time to listen to your body, not your ego.”

Move your intervals inside.

If you can avoid doing intervals outside when the temperatures dip into the single digits, do so. It’s not so much the running that is the issue but the increased breathing rate during intervals that can cause the problem. It’s for that very reasons that the international ski federations do not allow races to take place if temperatures are below -4F to try to limit exposure of the athletes. Think of this as improving the quality of the work you are able to do.

Invest in a mask.

A Buff will not do. A Buff is great at protecting your skin from cold air, wind, and sun exposure. What it cannot do is effectively warm the air you are inhaling. There are relatively affordable masks designed exactly for the purpose of training and racing in extreme cold. AirTrim, made popular by Scandinavian skiers, is a great product.

Shorten the total duration.

Part of the lung equation is a combination of how hard you are working and how long you are working. Along with moving the hard work inside when the temperatures dip below zero, think about shortening your total workout length. Cold exposure is harder on your body metabolically (you have to stay warm after all) and so your typical run will have a higher stress load on your system.

Corrine Malcolm has a B.S. in Health and Human Performance, and she is a Masters candidate in Biomedical Physiology. In 2016, she won the USATF 50 Mile Trail Championships and represented the US at IAU Trail Running World Championships. It is her passion to combine two of her loves, science and sport, as a coach for CTS.

References

  1. Rundell, K., & Jenkinson, D. (2002). Exercise-induced Bronchospasm in the Elite Athlete. Sports Medicine, 583-600.
  2. Kippelen, P., Fitch, K., Anderson, S., Bougault, V., Boulet, L., Rundell, K., Malcolm, S., & Mckenzie, D. (2012). Respiratory health of elite athletes- preventing airway injury: A critical review. British Journal of Sports Medicine, 471-476.
  3. Sheel, A., Macnutt, M., & Querido, J. (2010). The pulmonary system during exercise in hypoxia and the cold. Experimental Physiology, 422-430.
  4. Boulet, L. (2012). Cough and upper airway disorders in elite athletes a critical review. British Journal of Sports Medicine, 46(4), 417-21.
  5. Molis, M. A., & Molis, W. E. (2010). Exercise-Induced Bronchospasm.Sports Health: A Multidisciplinary Approach,2(4), 311-317. doi:10.1177/1941738110373735

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Comments 10

  1. What a fascinating and informative article! I work with skiers of all kinds, so this is great information for me to pass along. Also explains why my husband, a lifelong skier and hockey player, starting getting cold induced breathing trouble in his 50’s. Thanks for a great read – I will share with my clients!

  2. Very interesting! I never had issues until I moved from a tropical to a cold climate. Years after living in Chicago, I developed EIB and need to use an inhaler for high intensity excercise (indoors or out). And note that I never went outside un temps under 35-40F! My husband has it worse. He gets pneumonia every February unless he stays indoors all winter.

  3. Thanks for this enlightening article Corrine.
    I used to regularly climb 8k in 4 or 5 hrs. here in Palm Springs, Ca. almost weekly.
    Most climbs were fine, but occasionally, I would literally feel like I was an out of shape mess.
    Every little section that kicked up, brought me into a zone, (much lower threshold than normal), of almost gasping for air.
    After much study, I thought it could be related to lack of hydration. I drink more than most, (usually close to a gallon on a climb like that), including electrolytes.
    I’m wondering if 30 years of desert, dry-air training, (used to run some trail marathons & 50k’s), plus my current regular training here, (including road bike rides in 100+f), may be causing / have contributed.
    I can still train hard, still get very heat-acclimated where I can handle our conditions, but occasionally have one of those days.
    Any thoughts appreciated,
    Scott

    1. Hi Scott,
      Thanks for your interesting question. Yes lots of desert, dry-air training over the years could cause EIB. Interestingly there is no literature on total-body hydration and EIB symptoms, that being said, anecdotally I do know some athletes with diagnosed EIB who do think their symptoms are worse when they are dehydrated.
      I wrote an article for irunfar about EIB and other similar breathing conditions that we see in ultra runners that you might find interesting: https://www.irunfar.com/2018/04/take-my-breath-away-non-asthma-breathing-problems-in-endurance-running.html

      Corrine

      Corrine

  4. Corrine, appreciate this article and noting cold and the long term effects of exercising in it as something that can damage the lungs. One question I have is in your opinion, how cold is too cold to exercise? I know -4 F is a guideline. BUT!!! At 50 now, growing up in michigan and truly enjoying winter sports, all my life, I am observing my friends who I played hockey with growing up, seem to be developing more respiratory/pulmonary problems, EIB, at an alarming number. I can’t say its age at this point because they have started having trouble with EIB for example since we started hitting 40. With temps not being that cold playing ice hockey, compared to outdoors sports, I point it to the intense efforts given in hockey. I think you described it accurately in giving work beyond one’s physiological capacity that damages the lungs when exposed to cold. I also think that giving that amount of effort and starting at a young age or in developing lungs may contribute to problems. Can you give any reason for this or have any studies, please share and last, if you had a temp you would say avoid going out in to ski, or hike or bike, without a mask what would it be. All the best.

    1. Hi Heath, yes EIB is actually really common in hockey players, speed skaters, and even swimmers because it’s a combination of ventilated rapidly and inhaling irritant. That irritant for hockey players is actually thought to be the ice resurfacing agents, and for swimmers the chlorine. There’s currently no set temperature recommendation for when to put a mask on, and it would likely change based on the population (age, general health, etc). For going out in colder temperatures I would mostly pay attention to your effort level, with single digit temperatures, keeping your ventilation rate lower (easier effort). There is more and more research coming out trying to better look at the longterm effects of exercising in adverse environments, but a lot of it right now if using cautious self judgement.

  5. Corrine, this is a really helpful article and gives me insight into what a doc diagnosed me as having this past summer, when I had respiratory distress after a summer of high-altitude training and then “gunky” raspy lungs, shortness of breath and inability to breath deeply during the nighttime of the Ouray 100 (high altitude cold/dry air). He said I was experiencing exercise-induced bronchial spasms gave me an inhaler to use prophylactically next time I’m training or racing like that; do you think albuterol will help the condition of EIB? Thanks for your info.

    1. Sarah, I had no idea this happened last year! It’s scary when you don’t know what it is. We do see EIB develop in those long cold dry air (altitude is notorious for) during high attitude races like Leadville, The Bear (+dust), HardRock, etc. If it is EIB an inhaler should help manage symptoms when they arise, as it’s a bronchodilator. If it is exercise-induced laryngeal obstruction (EILO, formerly known as vocal-cord dysfunction) a bronchodilator won’t work, but it sounds like they have you on the right treatment plan. I wrote an article in 2018 for irunfar in greater detail about all these different breathing problems we see in ultra runners: https://www.irunfar.com/2018/04/take-my-breath-away-non-asthma-breathing-problems-in-endurance-running.html

      1. Super helpful, thanks Corrine. Yes, my lungs were a big limiting factor for me last summer and I believe ultimately caused my DNF at Ouray after 26 hours because I couldn’t get the oxygen my system needed, so my pace slowed to a crawl. I was literally pausing every couple of steps to try to catch my breath, but it hurt to breathe in and I could hear & feel fluttery and raspy crud in my lungs. I was catastrophizing that it might be high-altitude pulmonary edema, which added to my stress, but doc said no, “just” bronchial spasms & constriction. I really need to manage these symptoms if I hope to ever succeed in a high-altitude long ultra. Really appreciate your med/sci articles.

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