Is it OK to exercise when you have a cold? I have been feeling under the weather recently with a chesty cough and runny nose, but I’m desperate to leave the confines of my sofa. Will working out make me feel worse?
There’s a rule of thumb that says, if you must exercise during a cold, it is OK if your symptoms are above the neck, but not if they’re below. Personally, if I have a badly bunged-up nose and crashing headache, the last thing I feel like doing is pounding a treadmill. In fact on the rare occasion I get a cold, I’m secretly pleased to have the perfect excuse to swap the gym for n extra hour in bed.
It is the second part of the rule of thumb that really matters: your chesty cough suggests you should wait until your symptoms have cleared up plus a couple of days, before you resume your workouts.
Exercise is in its own right a stress on the body’s immune system. During a strenuous physical workout your body accumulates toxic waste as a natural consequence of the extra energy it is creating, and your immune system has to get to work on clearing up the resulting debris. We know that, all things being equal, this process is harmless. Indeed, over time, regular moderate cardiovascular exercise helps to strengthen the body’s immune system, so you are less likely than the average person to get ill (this is especially true the older you get).
When you have an infection, however, all is not equal: your immune system is already busy fighting off the illness, so it’s really not helpful to put it under further strain with a tough workout. If you do, your cough will probably take several days longer to clear up than if you rested up.
There’s another more serious danger, too. If your cold is viral, or is more like flu, or you have a fever (raised body temperature), there’s a slight chance that the infection will affect the muscle wall of your heart. Exercise in such circumstances can be extremely dangerous, and because there is no obvious way of knowing whether this is the case, the only sensible option is to lay off until you are recovered.
You may have been told it’s OK to do “gentle” exercise, and that may be true. But what is “gentle”? The people most likely to want to exercise during illness tend to be the keenest among us. If your idea of gentle is a steady 10km jog, you are best off languishing on your sofa for a while longer.
Regular exercisers often get anxious that they will lose fitness during a layoff for illness. This will not happen over the short-term. Upon your return you should always go easy for the first couple of workouts, building up gradually over two to three weeks until you are back to your pre-illness level of workout and feeling great.