Is It Possible to Exercise Too Much?

dear all

For apparently healthy people, there simply isn’t much evidence of a U- or J-shaped mortality curve, with mortality rising at very high levels of activity. Several recent studies have reinforced this, including a study^[7] from Sweden on physical activity and the risk for heart failure, which followed almost 40,000 people for more than a decade and showed that the protective effects of activity were more robust than the differences in traditional risk factors for heart failure might suggest.

In their defense, the individuals who are promulgating the “too much exercise hypothesis” argue that they are talking about a very small subset of people who participate repeatedly in marathons and triathlons and are way out there on the “dose” part of the curve.^[8]

A new study^[9] from the outstanding exercise cardiology research group in Dallas shows that intensely competitive lifelong master athletes have hearts that remain highly compliant as they age and retain impressive levels of ventricular performance. Earlier studies on ultramarathoners have shown that they have big coronary arteries that also dilate more.^[10] These physiology studies would seem to refute worries that too much exercise might make the heart stiff and injure the coronary arteries over time. On the population front, data from Sweden^[11] on nearly 75,000 men and women who have participated in long-distance marathon skiing show that those who finished more races (and presumably trained for more years) had lower mortality. So, in terms of mortality in healthy people, data that support the “too much exercise hypothesis” are hard to find

Exercise is not a “vaccine” against coronary artery disease in specific populations or against mortality in general, but it does have powerful protective effects with pretty well-described dose-response curves for mortality and cardiovascular outcomes. Thus, maybe we should all be worrying more about the vast majority of people who do nothing vs yapping about the unproven and hypothetical possibility that a tiny group of people might be doing too much

from medscape