Is there such a thing as too much exercise?! An article published in todays Mayo Clinic Proceedings discusses exercise and longevity, and with very appropriate timing given the upcoming marathon season. Accumulating evidence suggests that exercise practices which are ideal for promoting health and longevity may not necessarily be the high intensity, high volume endurance training, but are more likely to be more moderate physical activity or shorter sessions of vigorous training. One would assume that the longer and more vigorous the activity, the more benefit that accrues, but the studies show something different. The studies show that cardiac and mortality benefit continue to increase from none.....to low levels....to moderate levels.....to a reasonable amount of vigorous activity (30 min 5 times a week)......but extreme exercise, which can cause cardiac overuse injury (with elevations in certain cardiac blood markers to prove it) may actually increase the possibility of adverse cardiac consequences. This can range from sudden cardiac death, to rhythm disturbances of the heart, to accelerated plaque formation, to premature aging of the heart. In a study of over 1000 individuals followed for 10 years, the most sedentary group had a two to four fold increase in risk of heart attack and death, while the group performing strenuous activity on a DAILY basis were also TWICE as likely to die as the group performing more moderate physical activity. More intense exercise of more than 5 hours a week beginning in the 30s has been linked to higher rates of atrial fibrillation later in life. On the contrary, moderate physical activity was shown to decrease atrial fibrillation later in life. Interestingly, in a large group of competitive cross country skiers, those with the most races completed and best times had the highest chances of atrial fibrillation (an irregular rhythm which increases stroke risk). Wait.........what??? This doesnt make sense...... How about the upcoming marathon? Long term marathon running was paradoxically associated with increased, NOT decreased, cardiac plaque. Cardiac catheterizations in long term marathoners showed significantly greater hard and soft plaque than sedentary controls. Bottom line....too much of a good thing might be bad, and thats what these studies show. I still believe strongly that exercise is medicine......important to do MOST days of the week. Vigorous activity is fine, but more than 60 minutes a day, more than 5 days a week seemed to be the tipping point where benefits were exceeded by risks. My best advice to patients (which I give regularly) is stop the chronic cardio and do some strength training.
Posted on: Mon, 22 Sep 2014 23:39:13 +0000
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