Can Running in the Cold Hurt Your Lungs?

by Ryan Drummond of Threshold Athletic Coaching

Here in the northeastern U.S, winter has arrived, and with it lower temperatures for running outdoors. Many of us are anecdotally aware that running in the cold can be “hard on your lungs.” But what does that actually mean, and how cold does it have to be to be concerned about the effects?

The effect of cold weather running is measured with spirometry tests performed pre- and post- exercise in temperature controlled environments. Theses tests measure the volume of exhaled air and the rate of airflow at specific points of exhalation. Runners are tested in temperature ranges from 32 F to -4 F (0 C to -20 C) and at varying intensities from aerobic to VO2max zones. Reductions in airflow can mean the airways are restricted to due to the cold (and dry) air entering the lungs. This condition is called Exercise Induced Bronchoconstriction (EIB), also informally called Exercise Induced Asthma.

For low-intensity exercise (70% VO2max and below), there is not much difference in airflow testing pre and post exercise. So for long runs and easy runs, there is not much to worry about concerning EIB. (Assuming one has normal lung function.) But as intensity and breathing rates increase, airflow begins to suffer around 14 F (-10 C) and colder. If you must run high intensity workouts in these conditions, it is recommended to keep your sessions short and to warm the air as much as you can with a buff our other breathable clothing option around the mouth. Nasal breathing also helps as that airway is designed to warm and humidify incoming air before entering the lungs.  

References:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7739679/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6031196/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5705483/
https://www.mayoclinic.org/diseases-conditions/exercise-induced-asthma/symptoms-causes/syc-20372300
https://www.aafp.org/afp/2004/0301/p1107.html