1. I think I’m coming down with something
The most important piece of advice a doctor can give a runner is a fairly simple rule of thumb – if you’re running a fever, you definitely shouldn’t go running. Otherwise you don’t really have to give up your run if you’re feeling a bit under the weather. But you also shouldn’t push yourself to your limits or beyond. Moderate exercise can activate your immune system. Intensive activity, on the other hand, doesn’t boost your body’s defences, but weakens them instead. Marathon runners, for example, need several weeks for their immune systems to return to normal. After an illness with fever, it’s usually best to take a one-week break from running. Top athletes – or all athletes, really – can be somewhat neurotic when it comes to their training schedules, however. If they aren’t able to work out for three days, they have the feeling that they’re going to lose all the progress they’ve made. To put it bluntly, that’s just ridiculous. In the long term, a one-week break will not harm your performance. Quite the opposite, in fact – your illness will linger much longer if you start exercising again too soon. And if you have a fever, in the worst case there is a danger of the heart muscles becoming inflamed, a condition that can even be fatal.