The Flu and You.

An apple a day may help keep the doctor away, but as we head into the heart of the cold and flu season, low-intensity exercise may be just what you need to shore up your immune system. Intend to beat the odds this winter? Don't plan on it. According to the Centers for Disease Control and Prevention, the average American adult suffers two to three respiratory onslaughts a year.

And while experts' opinions differ on whether exercise will help diminish the severity of a cold, most docs and profs do agree on one thing: If you decide to work out, take it easy. Standard practice is to employ an "above-the-neck" check on symptoms. Got a runny nose or a scratchy throat? It's probably OK to begin working out at a lower intensity. If your symptoms retreat after the first few minutes, you may intensify your exercise.

Below-the-neck symptoms, such as vomiting, aching joints, or a hacking cough, are a different story. Exercising under these conditions can actually depress your immunity, leaving you worse off than you were to begin with. Do yourself a favor: grab a bowl of chicken soup and snuggle up under the covers. Sometimes inaction is the best action of all.

Finally, use common sense when you start to feel the portents of a cold or a nasty, lingering flu. Avoid spaces that offer poor ventilation, scrub your hands often with a disinfectant soap, and try not to overdo things. And don't forget to throw that apple into your workout bag.