Doctor K: How much exercise is too much?

Sat., May 16, 2015

Anthony L. Komaroff Universal Uclick

DEAR DOCTOR K: I like really intense exercise, so I expect things to hurt when I’m working out. How do I know if I’m pushing myself too hard?

DEAR READER: The expression “no pain, no gain” has misled many an exercise enthusiast. The fact is, pain and other symptoms during exercise are not normal. You should pay attention when your body is sending you warning signs.

Let’s start with what you should expect. At the height of a workout, you should be breathing a little harder. You should still be able to talk, but you shouldn’t be able to sing. You should feel your heart beating faster than normal during exercise. And you may feel your muscles burn a little.

But certain symptoms during exercise can indicate trouble. What doctors are most worried about is coronary artery disease (CAD). In CAD, atherosclerosis narrows the arteries that supply blood to the heart. When the heart is asked to work harder during exercise, it needs a healthy blood supply most. When the blood supply is reduced, the exercising heart “complains” by causing various symptoms:

• CHEST PAIN. Any chest discomfort that begins after starting exertion is cause for concern. The same thing is true of discomfort in the jaw and shoulders. It’s of particular concern if the discomfort resolves within a minute or two after stopping exertion.

• SHORTNESS OF BREATH. If you get breathless doing an activity that didn’t bother you a week ago, then something is wrong. CAD can cause new and unusual breathlessness without causing chest discomfort.

• LIGHTHEADEDNESS. CAD can cause irregular heart rhythms that make the exercising heart pump inefficiently. If not enough blood is being pumped to the brain, a person feels lightheaded. CAD can lead to the symptom of lightheadedness even when a person has no chest discomfort or breathlessness.

Feeling faint can sometimes happen because of dehydration. Drink plenty of water to prevent this from happening. It can also be a side effect of blood-pressure-lowering medication if you feel lightheaded in the 30 to 60 minutes after you exercise.