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November 08, 2017

Am I harming my airways by running outside in the cold?

'Infrequently Asked Questions' seeks the answer

For runners, there's no more disappointing a moment than when the weather turns too cold to run free-as-a-bird in a tank-top and shorts and, more uncomfortably, when the rapid breaths start sucking in blasts of cold air. 

It's worth asking: Is that frosty air doing you harm?

Curious, we reached out to Gregory Kane, pulmonologist at Jefferson University Hospital

Is it bad for your airways to be running in the cold? I think we all experience the discomfort of breathing in that cold air this time of year,  but it's worth wondering if it's harmful.

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It's not bad at all. But there are some important effects cold air has on the lungs that are really important. The one most relevant to comment on is that cold air is a trigger for exercise-induced asthma. And what's been shown is really scientific in its level of understanding, and that is that cold air leads to an inflammatory release from the airways, and in asthmatic patients, this can trigger a significant asthma attack and limit their ability to exercise effectively. 

This phenomenon does not necessarily occur in a general population, but it's not unusual for people to feel a little bit of trouble breathing in really cold air and the way that you can manage this, if you're an asthmatic patient, is you can retreat with a rescue inhaler, but you can also wear a scarf around the mouth. What that does is create a barrier of air so you can have a little less cold air when you inhale and get a chance for your face and body to warm the air before it pulls in. And also, warming up before you exercise in cold air. It seems that sudden exposure triggers reaction more dramatically than a protracted exposure with a long warmup.

And when you say warmup here, you mean the exercising kind?

Yeah, if you're going for a long walk in the cold, do some stretches or knee-lifts before you go out. If you go jogging in the cold air, do some running in place before going out, along with stretching. It could be doing a little bit of indoor running before you go out. And it could be you keep that scarf more tightly around your face until you really got into your run more fully.

And this applies to people who already have asthma?

Yes, although my sense in talking to people who don't have asthma, they occasionally experience a little difficulty breathing in relation to cold air, whether it relates to some low-level inflammation that's not necessarily at the level of a true diagnosis of asthma or just a sensation hard to describe. But it's not unusual for someone without asthma to experience that reaction.

So we need more research to really know how much trouble the cold air might be causing? 

I think we do. And just to highlight the need for additional research, one of my colleagues a little more than a decade ago did testing among high-school and junior-high athletes in the city and found a surprising level of exercise-induced asthma in city kids. These were kids who did not have a preexisting diagnosis of asthma, did not have asthma suspicion, and they underwent typical tests used to detect exercise-induced asthma and a surprisingly high portion had it. And what that reminds me is not everybody knows they have exercise-induced asthma and experience symptoms in cold air and don't realize what it may be coming from.

Is there a stat for that, people who have [exercise-induced asthma] but don't know?

There's no good statistic. But, the overall incidence appears to be about 7 percent. And in certain calculations, it's higher, particularly in minority populations in inner cities and in persons with underlying allergies. And persons who have certain exposures. So, we know there are probably patients out there who do not realize they have asthma and are experiencing symptoms they don't understand and would benefit from medical intervention--the benefit of it is they could take preventive inhalers or symptom-treatment inhalers and get instruction on how to modify their routine, such as avoiding allergens or making modifications we just discussed.

The problem with running outside is the rate of breathing combined with the cold, right? 

That's correct. 

For example, it's not as if chugging a cold milkshake would cause the same reaction in the airways.

Yes, I think you're right. To put this in perspective, I will tell you that you can trigger an asthma attack in room temperature air with rapid breathing [because our body temperature is higher than an average room] ... It's related to the temperature of the air and the movement of the air in and out of the trachea.

I would say there's really no damage necessarily to the airways; it's really a temporary effect. There might be soreness or tightness but those should be temporary effects and not cause lasting damage.

The big picture, for those without asthma, is there's no harm to running outside in the cold. Except the experience of temporary irritation. Right?

That's correct.