Emerging scientific evidence points to a possible threshold of intensity, duration or distance that if crossed could limit the benefits of physical activity. A pair of new studies in the journal Heart raise concerns that prolonged, extreme exercise could negatively affect heart health for certain groups.
In the first study, German researchers followed more than 1,000 people with stable heart disease for a decade. Participants' exercise habits ranged from less than two times a week to more than four times a week. WebMD reports that researchers found:
Compared to those who got regular exercise, the most inactive people were about twice as likely to have a heart attack or stroke, and were about four times more likely to die of heart disease and all causes, the researchers said.
However, Mons' team also found that those who did the most strenuous daily exercise were more than twice as likely to die of a heart attack compared to those who exercised more moderately.
For the second study, Swedish researchers evaluated the potential of endurance exercise to increase the risk of atrial fibrillation. It included 44,000 men who were surveyed about their previous levels of physical activity certain ages and then had their heart health monitored for 12 years. More from the article:
Those who had done intensive exercise for more than five hours a week when they were younger were 19 percent more likely to have developed a heart rhythm disorder called atrial fibrillation by age 60 than those who exercised for less than an hour a week.
That risk increased to 49 percent among those who did more than five hours of exercise at age 30 but did less than an hour a week by the time they were 60. Participants who cycled or walked briskly for an hour or more a day at age 60 were 13 percent less likely to develop atrial fibrillation.
Authors of an accompanying editorial concluded that "the benefits of exercise are definitely not to be questioned," and that the findings could be useful to "maximize benefits obtained by regular exercise while preventing undesirable effects."
Previously: Lack of exercise shown to have largest impact on heart disease risk for women over 30, Study reveals initial findings on health of most extreme runners, Is extreme distance running healthy or harmful? and Untrained marathoners may risk temporary heart damage
Photo by Robin McConnell