This article was originally published in the April 2023 issue of UltraRunning Magazine. Subscribe today for similar features on ultra training, racing and more.
Many of us contend with training in cold weather, some of us even in polar climates. In these regions, where very cold temperatures (-22 degrees), snowstorms and strong winds are commonplace, just setting foot out the door can be a challenge. In this month’s column, I explore how training in the cold can affect your physiology and the steps you can take to minimize the impact on your sporting longevity.
I generally find it harder to train in the winter. Breathing is tougher and the cold weather sometimes makes me cough. Am I doing long-term damage to my lungs? – Sammy A.
Before answering the question, here’s a brief primer on the respiratory system. Before reaching the lungs, the air we breathe must journey through a series of tubes that warm and humidify them. At rest, this task is accomplished quite easily in most people. However, during exercise, when breathing rates increase, the capacity of the “conducting airways” to warm and humidify the air is often exceeded. This allows unconditioned air to reach the small airways, causing them to become dehydrated and inflamed. In turn, they can sometimes constrict and produce mucous (1). Running in the cold can therefore cause a cough in susceptible people.
If repeated over a prolonged period, this mechanism of airway dehydration and inflammation can cause long-term injury to the respiratory system (2, 3). So, the answer to your question is: potentially, yes. People who are susceptible can develop a condition known as exercise-induced bronchoconstriction (EIB) which causes asthma-like symptoms (cough, wheeze, mucous production) during exercise. The prevalence of EIB in the general population is around 10% but is more than twice as common among athletes, especially endurance athletes (4), women and athletes competing in winter sports (5). There isn’t enough data to estimate the prevalence in ultrarunners, but I see little reason why we would be an exception. In fact, biomarkers of airway inflammation increase with exercise duration (6, 7), suggesting we may be particularly at risk.
In ultrarunning, a willingness to train and race in extreme conditions is not just common, it’s considered a virtue. Indeed, we’re perhaps not the best group of athletes at carefully balancing the risks and benefits of competition. But, in my opinion, it’d be unwise to prioritize your commitment to the sport above your long-term respiratory health. This means that, if you live in a harsh climate, where the air is particularly cold and dry during the winter, take some steps to minimize its influence on your lung function. If you have access to the facilities, you could do more training, or a portion of your long runs, indoor on the treadmill. You could try wrapping a buff over your nose and mouth, as the microfibers will trap some of the warm and humid air you expire, allowing it to recirculate. And for people who suffer more intensely in the cold, especially those with EIB or pre-existing asthma, commercial heat exchanger masks can warm and humidify the inspired air. They’re not a panacea, but studies indicate that they may reduce airway heat and water loss during exercise and partially mitigate EIB when exercising in cold, dry environments (8).
How does training through a cold winter affect my performance in a warm race in the spring/summer?
–@ruthb1987
The systems you’re training during the winter—metabolic flexibility, aerobic capacity and economy and musculoskeletal conditioning—are essentially the same as those you’d train in the summer. So, don’t worry that winter training might deprive you of important physiological adaptations. That said, your nutrition and hydration requirements will differ between cold and warm conditions. For example, sweat rates are generally greater in the heat, and cold weather blunts your thirst response (9). The warm weather is also known to increase the body’s dependence on carbohydrate as an energy source (10) and this may predispose to early glycogen depletion. Therefore, the nutrition and hydration strategies you’ve formulated throughout winter training will need to be adapted for racing in the spring. If your event is contested in particularly hot conditions, then some form of structured heat acclimation protocol—repeatedly exercising in the heat to induce favorable thermoregulatory adaptations—may be beneficial (11).
It seems like I know a lot of endurance runners with Raynaud’s. Is there a connection? How do I make the effects less annoying? –@justrunthere
Raynaud’s is a condition where blood vessels in the limbs, particularly hands and feet, periodically and temporarily narrow due to an oversensitivity to cold temperatures, stress and/or anxiety. It can cause pain and discomfort, pins and needles and paleness in the skin. In rare cases, it can cause ulceration of the fingers and toes. The exact cause of Raynaud’s is not known, but between 3–5% of people have the condition, and it’s slightly more common in females (12). There’s very little data on the prevalence in athletes and exercisers. In fact, the only data I’m aware of from ultrarunners showed a prevalence of just 0.5% (13), although this was a relatively small sample from a survey on self-reported illnesses. It could be that Raynaud’s “appears” more common in distance runners because we spend long periods running in the cold, further compromising blood flow to the extremities and thereby exacerbating the symptoms. Cold weather can even trigger Raynaud’s.
Mild cases of Raynaud’s cannot be cured but instead prevented, treated and managed. The obvious advice is to dress appropriately for the temperature. If it’s cold, wear gloves (battery-powered options are available), extra layers and thick socks to prevent excessive heat loss from extremities and retain circulation. Try carrying hand warmers with you on long runs to use if your Raynaud’s is triggered. There is some evidence that supplements containing or stimulating the release of nitric oxide (e.g., beetroot juice, L-arginine) might help improve symptoms of Raynaud’s syndrome, but the evidence is mixed (14–19). If Raynaud’s is causing you severe discomfort, or if there’s concern about long-term tissue damage, your physician might prescribe medications (e.g., calcium channel blockers or vasodilators) which relax and dilate the blood vessels to promote blood flow. In extreme cases, surgery or chemical injections to target the nerves might be indicated. Ultimately, if you have a new case of Raynaud’s, or if it’s disrupting your quality of life, speak with your primary care provider.
References
- Gotshall RW. Exercise-Induced Bronchoconstriction: Drugs. 2002;62(12):1725–39.
- Carlsen K-H. Sports in extreme conditions: The impact of exercise in cold temperatures on asthma and bronchial hyper-responsiveness in athletes. Br J Sports Med. 2012;46(11):796–9.
- Kippelen P, Anderson SD. Airway injury during high-level exercise. Br J Sports Med. 2012;46(6):385–90.
- Boulet L-P, O’Byrne PM. Asthma and Exercise-Induced Bronchoconstriction in Athletes. N Engl J Med. 2015;372(7):641–8.
- Pigakis KM, Stavrou VT, Pantazopoulos I, Daniil Z, Kontopodi AK, Gourgoulianis K. Exercise-Induced Bronchospasm in Elite Athletes. Cureus. 2022;14(1):e20898.
- Araneda O, Guevara A, Contreras C, Lagos N, Berral F. Exhaled Breath Condensate Analysis after Long Distance Races. Int J Sports Med. 2012;33(12):955–61.
- Vezzoli A, Dellanoce C, Mrakic-Sposta S, et al. Oxidative Stress Assessment in Response to Ultraendurance Exercise: Thiols Redox Status and ROS Production according to Duration of a Competitive Race. Oxidative Medicine and Cellular Longevity. 2016;2016:1–13.
- Jackson AR, Hull JH, Hopker JG, et al. The impact of a heat and moisture exchange mask on respiratory symptoms and airway response to exercise in asthma. ERJ Open Res. 2020;6(2):00271–2019.
- Kenefick RW, Hazzard MP, Mahood NV, Castellani JW. Thirst sensations and AVP responses at rest and during exercise-cold exposure. Med Sci Sports Exerc. 2004;36(9):1528–34.
- Gagnon DD, Perrier L, Dorman SC, Oddson B, Larivière C, Serresse O. Ambient temperature influences metabolic substrate oxidation curves during running and cycling in healthy men. Eur J Sport Sci. 2020;20(1):90–9.
- Pryor JL, Johnson EC, Roberts WO, Pryor RR. Application of evidence-based recommendations for heat acclimation: Individual and team sport perspectives. Temperature (Austin). 2019;6(1):37–49.
- Pope J. Raynaud’s phenomenon (primary). BMJ Clin Evid. 2013;2013:1119.
- Hoffman MD, Krishnan E. Health and exercise-related medical issues among 1,212 ultramarathon runners: baseline findings from the Ultrarunners Longitudinal TRAcking (ULTRA) Study. PLoS One. 2014;9(1):e83867.
- Khan F, Belch JJ. Skin blood flow in patients with systemic sclerosis and Raynaud’s phenomenon: effects of oral L-arginine supplementation. J Rheumatol. 1999;26(11):2389–94.
- Shepherd AI, Costello JT, Bailey SJ, et al. “Beet” the cold: beetroot juice supplementation improves peripheral blood flow, endothelial function, and anti-inflammatory status in individuals with Raynaud’s phenomenon. J Appl Physiol (1985). 2019;127(5):1478–90.
- Freedman RR, Girgis R, Mayes MD. Acute effect of nitric oxide on Raynaud’s phenomenon in scleroderma. Lancet. 1999;354(9180):739.
- Rembold CM, Ayers CR. Oral L-arginine can reverse digital necrosis in Raynaud’s phenomenon. Mol Cell Biochem. 2003;244(1–2):139–41.
- Curtiss P, Schwager Z, Lo Sicco K, Franks AG. The clinical effects of l-arginine and asymmetric dimethylarginine: implications for treatment in secondary Raynaud’s phenomenon. J Eur Acad Dermatol Venereol. 2019;33(3):497–503.
- Agostoni A, Marasini B, Biondi ML, et al. L-arginine therapy in Raynaud’s phenomenon? Int J Clin Lab Res. 1991;21(2):202–3.