I’ve been fighting some relentless cold bug for the past few weeks, it seems. Nothing serious, just feeling depleted. But it’s not getting better, and I woke up this morning wondering whether my immune system had taken the day off. On days like this, my body tells me to get more sleep and generally take it easy. Then I’ll go do some work in the yard or climb on my bike and feel recharged almost immediately — but only temporarily.
It’s a bit of a puzzle to me, this relationship between exercise and my immune system. Should I push through my exhaustion and force myself to work out in order to rev up my body’s defenses, or is it more prudent to spend the day on the couch with a purring cat and a good book? According to this 2009 study from the University of Illinois, it appears the answer is both yes and no.
Viruses like the one I suspect is knocking me down these days, trigger the production of what are called T1-helper cells as a first line of defense. These cells create inflammation in the body to fight off the virus. This is all fine, up to a point, but if that inflammation lingers too long, it can begin to do more harm than good. That’s when the immune system sends in reinforcements in the form of T2-helper cells, which are designed to cool the inflammation. In an ideal situation, this all happens seamlessly, and you soon start to feel better.
Moderation to Build Immunity
But if, like me, you’re battling some stubborn bug to a draw, the intensity and duration of your workout can tilt the balance of power. If you go too hard or too long, you may suppress the initial immune response and leave yourself open to a full-on viral invasion. And if you ignore exercise altogether, those T1 cells could hang around too long and begin to do some damage. Moderate exercise, on the other hand, can deliver those T2 cells at the appropriate time, bolstering your defenses and knocking out the virus.
That’s the idea, anyway. And it probably explains why my symptoms seemed to vanish this afternoon while I was raking leaves. I’ll take that to mean I was exerting myself just enough. But now, here I am slumped over a keyboard and longing for a nap. So what do I do? Climb on my bike? Crank out 30 pushups?
Maybe I need to ponder my options for a bit. On the couch. With a book. And where did that cat go?