Should you run when you're sick?

As I recover from a cold (and hope it doesn't lead to a sinus infection), it seems appropriate to consider this age-old question: when the body is fighting off illness, should the athlete keep training? Should he or she train differently? If rest is required, how much rest?

I truly wish there were simple answers to these questions, but in my own experience I haven't found anything simple about the experience of training and racing when sick. Let's say that there are two extreme positions: "old school" and "new school." The old school approach is to consider illness to be one more form of weakness that can be overcome by effort. An old school athlete runs when sick, and eventually gets better and is stronger for the experience ("what doesn't kill me makes me stronger"). The new school approach is to consider illness as a warning sign that the body needs healing before it can resume training. The new school athlete takes two days off, gets better, and gradually works up to hard training again. ("What doesn't kill me still leaves me in a weakened, compromised state that inhibits progressive adaptation and improvement.") So which school is better?

I have taken both approaches in my own running career, and have dispensed both "old school" and "new school" advice to athletes I have coached. The results are inconclusive. Worse than that, the results are contradictory. I once ran a brilliant half-marathon while suffering from the early stages of a cold, and recovered surprisingly quickly. I once ran a 10K race with a cold and developed a frightening case of bronchitis that kept me out of action for nearly a month. I have done track workouts while sick that seemed to hasten my cure, and I have done track workouts when sick that seemed to bring on far worse bouts of illness than what would have been expected. I have skipped track workouts when sick in the hope that I would recover faster, and then have failed to recover faster. It has been, as they say, a mixed bag.

One reason to train through illness is that NOT training doesn't always make you feel better. I mean psychologically as well as physically. One reason to AVOID training through an illness is that hard training has been shown to temporarily weaken the immune system, not a good thing when you are harboring nasty germs.

If I had to summarize the moderate approach, I would say that one should fore-go HARD training while sick, but not necessarily take complete reset. I'd also say avoid all racing when sick unless it is a really important race, for example one you have trained for all season. Thus, if you have a cold or a sore throat or a headache, run easy. Easy running means making it completely aerobic - nothing that involves really hard breathing or placing your body in extreme duress. I think there's little risk that such moderate exercise will lengthen the duration of a common cold. On the other hand, don't do that killer 4 x 1M workout that you had planned. Don't go out for a 15 mile long run in sub-freezing temperature. In other words, don't extend yourself. When you're sick, you're more likely to break.

I haven't even mentioned one of the other factors that comes into play: hypochondria. It turns out that many runners are hypochondriacs. When under mental stress, such as when approaching an important workout or race, they experience symptoms of illness without the actual illness. Far from being crazy, these athletes are actually rather typical. One of the important reasons to not automatically shut it down when you are feeling the early signs of a cold, is to counter this natural tendency to "worry yourself sick." Hypochondria, like other forms of self-doubt, needs to be understood and confronted to be overcome.

Finally, there is the rare malady of the athlete who refuses to take time off, even when continuing to train is obviously counter-productive, if not dangerous. If hypochondria is the result of one kind of insecurity, its opposite is the result of another kind of insecurity: the fear that taking any time off at all is an unacceptable form of weakness. This is where a coach can be very helpful in setting limits that an athlete might not want to set for himself or herself.

So, to conclude, should you run when you're sick?

What, do I look like a doctor?