High-intensity exercise may raise heart attack risk
While exercise has always been part of a heart-healthy lifestyle, two new studies published in the journal Heart say that too much of it can raise the risk of heart attack or an arrhythmia later in life. In an editorial linked to the studies, two writers say the results show that more doesn’t always equal better and that perhaps high-intensity exercise may be better suited at certain points in life.
The first study was conducted by researchers in Germany, who assessed the frequency and intensity of physical activity in more than 1,000 individuals with stable coronary artery heart disease for 10 years. Participants were mostly in their 60s and had participated in a cardiac rehabilitation program to help them exercise regularly. The researchers tracked survival of all participants as part of the study. The results showed that though the most physically inactive were twice as likely to have a heart attack or stroke as those who were physically active and were four times as likely to die of all causes, they also indicated that those who did the most strenuous daily exercise were more than twice as likely to die of a heart attack or stroke.
In the second study, conducted by researchers in Sweden, more than 44,000 men between the ages of 45 and 79 were asked about their physical activity tendencies during the ages of 15, 30, 50 and during the past year of their life. For an average of 12 years, the researchers tracked the participants’ heart health to determine how many developed an irregular heart rhythm.
The results showed that men who exercised intensely for more than five hours a week were 19 percent more likely to develop an irregular heartbeat by 60 years of age, compared with those who exercised less than one hour a week. However, those who did slightly less-intense exercises - such as cycling or briskly walking - for an hour a day or more at the age of 60 were 13 percent less likely to develop an irregular heartbeat than those who did not exercise at all.
The authors of the editorial suggest that while exercise is important, maximum cardiovascular benefits are obtained if performed at moderate doses and that these benefits are lost with (very high) intensity and prolonged efforts.