Ask the Experts: Exercise Well

By Dr. Paul D. Thompson
Her Sports + Fitness

Should I run when I have a cold? How do I know if I'm too sick to exercise?

There are no hard and fast rules for exercising during illness--there is little in the way of solid medical research--so athletes must use common sense. Generally, if you're sick and don't feel like working out, don't. This is simply a corollary of the rule "listen to your body"--it's trying to tell you something.

You can take several days off a training schedule or routine without affecting your overall fitness level, so it's generally better to back off training when you're feeling under the weather. Be sure to get additional sleep and rest. But if a cold sidelines your training right before a big race, and you feel up to it, it's not necessary to cancel your plans.

The only time I prohibit a patient from exercising is when he or she has the flu with muscle aches. A good rule of thumb: If symptoms are only above your neck (like sneezing or a runny nose), you can keep exercising. But if you feel congestion in your chest or if your body aches, it's best to stop working out.

Why? Aches imply that the muscles are involved in the inflammatory process. Since the heart is a muscle, the presence of muscle aches raises the possibility that there is also cardiac inflammation. Some people even get rare viral infections of the heart called "viral myocarditis," which can cause abnormal heart enlargement and other serious problems, especially when the heart muscle is stressed, as it would be during a run. There is also evidence that hard exercise during a viral illness helps the virus survive, keeping you sicker longer.

I'm 40 and training to run my first marathon. My family is worried because they've heard about runners my age dying from heart attacks. Do I need to be concerned?

In a word: No. Multiple studies have shown the benefits of regular exercise outweigh the risks. Also, cardiac events such as heart attacks and sudden death during exercise are very infrequent. They seem much more common because these events are so widely covered by the media, but they are actually quite rare. Among high school and college female athletes, there is estimated to be only one death of this type for every 800,000 women per year. Such deaths are usually caused by inherited cardiac conditions. Among adults older than 30, there is approximately one exercise death for every 16,000 men per year. Almost all of these deaths are due to narrowing of the heart arteries from cholesterol deposits or atherosclerosis. There are even fewer deaths among adult exercising women because the onset of atherosclerosis in women is delayed.

The best approach to preventing such events is to avoid the well-known risk factors for atherosclerosis, such as high blood cholesterol, smoking and high blood pressure.

Of course, it's always a good idea to consult with a doctor before beginning a new program. Start your training slowly and progress gradually, and report any new or suspicious symptoms to your doctor. Some people who have cardiac events during a race had symptoms of heart problems that they ignored.