New findings published in the Mayo Clinic Proceedings suggests that you can have too much of a good thing when it comes to running and exercise.
According to a statistical analysis of frequent runners, individuals who run 30 miles or more a week have a significantly higher mortality rate than those who run less. Researchers believe certain cardiovascular events can be trigged by what they call, “excessive exercise.”
“[This is] the first data in humans demonstrating a statistically significant increase in cardiovascular risk with the highest levels of exercise,” said lead researchers Paul Williams and Paul Thompson. “Our analysis suggests that the benefits of running and walking do not accrue indefinitely, and that above some level, perhaps 30 miles a week of running, there is a significant increase in cardiovascular mortality.”
Thompson cautioned that the results apply to “cardiac runners,” or those runners who have suffered a previous cardiovascular event.
“It’s a big deal that these were cardiac runners,” he said. “We can’t say that the same results will apply to healthy runners. The two groups are very different.”
Reverse J-Curve
In their findings, researchers suggested that runners who suffered a previous cardiovascular event exhibited a “reverse J-shaped curve” in terms of mortality rate. In laymen’s terms, doctors found that some exercise was better than none, but at a point, too much exercise becomes more problematic than less exercise.
“The evolving picture on exercise is becoming more clear: no other lifestyle factor confers more benefits to health and longevity than does regular moderate physical activity, but excessive exercise may erode some of the benefits,” said cardiologist James O’Keefe.
For their study, researchers followed 2,377 runners and walkers who suffered a previous heart attack for more than 10 years. After analyzing the data, they found:
- Mortality rates decreased by 40 percent if the person ran/walked for roughly 18 miles a week.
- Mortality rates decreased by 60 percent if the person ran/walked about 27 miles per week.
- Those running 30+ miles a week had a similar risk as those who only ran/walked 7-9 miles a week, and they were 2.6 times more likely to suffer a cardiovascular event than those who ran in the mid-20s per week.
Dr. Silverman comments
This is an interesting study. Just like overstressing your feet can lead to stress fractures, overworking your heart after a heart attack can lead to another episode.
Although the findings are significant, the biggest takeaway form the article is that people who exercised in moderation after a heart attack SIGNIFICANTLY lowered their risk of another event, by 40-60 percent. Please, make time to get your workout in a few times a week.
Related source: Runner’s World