Exercise and your Immune Systems

[dolphinboy]

According to this WebMD article, regular exercise will boost your immune system and keep you from catching colds, flu, etc. Of course, you also have to eat well, wash your hands frequently and get enough sleep, but “studies have shown” that people who exercise regularly get fewer colds, etc.

Let’s stipulate that exercise somehow helps your immune system and that there is evidence showing that. What I can’t seem to find is the exact mechanism whereby regular exercise boosts something or increases the production of something that benefits your immune system. Can someone explain to me the relationship between regular exercise and an increased immune system? For example, do extra white blood cells get created when you exercise? Or something like that?

[dolphinboy]

Is there a doctor in the house? Someone must know the answer. I have never stumped this group before.

[nelliebly]

Definitely not a doctor, but someone with a compromised immune system who exercises a lot. This article in the New York Times may help:

In general, and this is true in both mice and men, says Jeffrey A. Woods, a professor of kinesiology and community health at the University of Illinois and one of the scientists involved, viruses evoke an increase in what are called T1-type helper immune cells. These T1-helper cells induce inflammation and other changes in the body that represent a first line of defense against an invading virus. But if the inflammation, at first so helpful, continues for too long, it becomes counterproductive. The immune system needs, then, at some point to lessen the amount of T1-mediated inflammatory response, so that, in fighting the virus, it doesn’t accidentally harm its own host. The immune system does this by gradually increasing the amount of another kind of immune cell, T2-helper cells, which produce mostly an anti-inflammatory immune response. They’re water to the T1 fire. But the balance between the T1- and T2-helper cells must be exquisitely calibrated.

[MikeF]

I know that I don’t get as many colds when I am on a regular workout schedule. I always attributed it to the fact that I sleep much better and assumed (or heard) sleep had something to do with the keeping the immune system in top form. That said, I have a cold right now and have been working out for months. No, IANAD.

[mmmiiikkkeee]

My (non-doctor) understanding is that exercise (and eating right and sleeping right etc…) basically makes the whole body more fit and reduces stress, which allows the rest of the body including the immune system to function better.

There’s no literal “boost” to the system… I think that term is misused. AFAIK you can’t really make your immune system stronger except by developing new antibodies which only comes by exposure to viruses (or immunizations). The actual immune response itself is the elevated temperatures and extra snot and so forth, and I don’t think anyone wants their immune system to kick into a higher gear and make them feel even more congested.

It’s more reducing the extra stresses on the body and allowing the immune system to function as well as it can, rather than making it work “better”.