Exercise Is Good For You

But some cardiologists worry that too much is bad for the heart. Lisa Rosenbaum examines their claims:

After reviewing the data and interviewing experts in the field, my own impression is that among people without known cardiovascular disease there is no compelling data to suggest that mortality significantly differs between moderate and extreme exercisers. There is thus no way to precisely define an upper limit of exercise for an average healthy individual. I suspect, though, that part of what sustains the “too much exercise can kill you” myth is the widespread recognition of the so-called exercise paradox. That is, while consistent exercise decreases the likelihood that you will have a heart attack, if you are destined to have one it is more likely to happen while you are exercising. That’s why no one can issue a blanket statement that extreme exercise is safe. It’s also why so many researchers have attempted to figure out how to make extreme exercise as safe as possible.