Is Too Much High – Intensity Exercise Bad For Your Heart?

Along with following a nutritious diet and avoiding risky behavior like smoking, part of a healthy lifestyle includes exercising regularly. But two new studies published in the journal Heart suggest doing too much high-intensity exercise may increase risks of dying from a heart attack or developing an irregular heart rhythm later in life.

In a linked editorial to the studies, two writers say the results reveal a “J-shaped curve” for health benefits of exercise, whereby more does not always mean better. They also say the research raises questions about intensity and duration of physical activity at different points in life.

The first study was conducted by researchers in Germany, who, for 10 years, 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.

High - Intensity Exercise

Currently, heart disease patients are advised to participate in up to an hour of moderate intensity aerobic activity at least five times a week. The breakdown of study participant activity was as follows:

  • 40% were physically active two to four times per week
  • 30% were physically active more than four times per week
  • 30% were physically active less than two times per week
  • 10% rarely or never did any exercise.

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, results showed that those who did the most strenuous daily exercise were more than twice as likely to die of a heart attack or stroke.

The researchers note that they took into account other influential factors that could have affected the results.

actors that could have affected the results.