Sunday, November 28, 2010

Run Run Rudolf

I consider myself a fairly healthy person and I rarely get sick. However, there is one activity that never fails to put me under the weather: flying. No matter how hard I try, no matter how much I wash my hands and try not to touch my face, any flight inevitably leads to some kind of illness. It usually ends up being a common cold, but I remember a nasty Christmas holiday spent in bed with a stomach flu. In any case, my recent flight home from San Diego was no exception, and here I am, still battling a stupid cold. So naturally, I looked for an article on how to prevent colds.

In a recent study, researchers followed over a thousand adults (18-85 years old) for 12 weeks during the fall and winter seasons. Over this time, the participants had to report two measures: any symptoms of upper respiratory tract infection (such as a cold), and how much they exercised.

While running in the cold winter air might sound like a counterproductive measure to prevent colds, the researchers found that participants who reported being physically active (aerobic exercise) five days a week or more experienced significantly less cold and flu symptoms (a 43% reduction in number of days with an illness). This relationship held true event when several factors were controlled for, such as dietary habits (eating lots of fruits and veggies) and stress levels.

Why might exercise prevent colds? While we don't have a clear cut answer to this question, animal studies suggest a few leads. When you exercise, you increase the circulation of cells that are important for immunity and that are involved in fighting off the bad guys. More specifically, exercise has been shown to boost macrophages (cells that eat up invaders) in your lungs. In addition, exercise can lower the levels of immunity-compromising stress hormones.

Is there anything exercise can't do? Now I need researchers to study how one can be motivated to exercise when they are sitting in a comfy chair by the fire with a mug of chai tea and a pile of work to do and it's below zero outside. Tell me something I don't know, right?

Reference: Upper respiratory tract infection is reduced in physically fit and active adults. (2010) Nieman DC et al. [Epud ahead of print].

4 Responses to “Run Run Rudolf”

Anonymous said...

This is great, SC! Fits with my experience, too - both the travel aftermath and being outside (even in cooler weather) -> no cold or reduced symptoms.

I've been thinking the whole fresh air vs. indoor trapped/multiplying viruses was the primary component of reasons for the results seen.

But, of course, I am willing to say a resounding 'no' to answer the question about what exercise cannot do. The next question you pose, well, I'll work on answer.

PS You might want to read my next post, hopefully up by tomorrow.

Thanks for your comment, Barbara! It's always nice when real life confirms the science.

I wish I could confirm that fresh air does the trick, but the study didn't distinguish from exercise indoors vs outdoors. I think that in addition to the fresh air, you have to get the blood moving. :)

I'll keep an eye out for your next post!

Carole said...

Wow! Same here! Just about every time I fly I end up with a cold, and I rarely get them. I always figured it was the re-circulated air (germs) on planes.

Thanks for your input, Carole! I too figure the plane thing is due to recirculating air. I also tend to bring snack food on plane rides, which I then eat with my hands, and that probably doesn't help, but I can't bear the thought of flying without a little bag of goodies. :)

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