"What does not destroy me, makes me stronger," said philosopher Friedrich Nietzsche. But he never tried getting on a treadmill when he had a mean head cold. For when it comes to exercising while ill, the Nietzchian work ethic should be discarded like a used Kleenex.
From the classic "no pain, no gain" mind-frame to the urban legend that exercise can help burn out a cold and shorten the suffering, misinformation abounds about setting limits on under-the-weather workouts.
"An easy way to think about whether or not to continue your exercise routine when ill is by using the 'above/below the neck' rule," says Bryan Stednitz, MS, Assistant Director Fitness and Wellness in the Recreational Sports division of Indiana University. Stednitz explains that symptoms above the neck (congestion, runny nose) typically mean you have a common cold. He suggests discontinuing your workouts in this case, but admits that some people opt to simply perform a shorter workout at a lighter intensity. He also notes that exercise releases catecholamines, better known as adrenaline, which can help ease the symptoms of a cold. However, exercise will not shorten the duration of the illness.
When it comes to symptoms that manifest themselves below the neck (nausea, vomiting, fever) there is no room for interpretation: Do not continue to work out.
"You should never work out with a fever," says Stednitz adamantly. "Your body maintains your core temperature within very narrow limits, so it's working a lot harder when you have a fever. Exercise will raise your temperature even further, putting you at risk for heat-related injury. As well, your body fluid may be diminished by up to 10 percent with a fever, and exercise could exacerbate this dehydration."
The best judge on whether to lace up the running shoes or slap on the bunny slippers is you. The only question is, are you smart enough to listen?
"The problem is most people don't listen to their bodies," says Stednitz. "Just keep in mind that your immune system is working harder when you're sick, so going lighter on exercise is not a bad thing."