Few would deny it: Running and other forms of cardio exercise benefit overall health.
But is there a point where adverse health effects are possible?
Questions about the safety of intense running are often raised following the death of a runner during a race. On Satuday, a 34-year-old North Kansas City man died at the Rock the Parkway half-marathon. Brandon Lee Russell, known as Flash, was described as an avid runner. He reportedly had no apparent health problems.
His cause of death remains undetermined and could be unrelated to running.
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Some in the running community advocate for light running regimens. James O’Keefe, a Kansas City cardiologist, is one such advocate. In his 2012 paper “Potential Adverse Cardiovascular Effects from Excessive Endurance Exercises,” he aimed to home in on the amount of running necessary to achieve maximal longevity. He found what some may consider light cardio workouts are more conducive to a longer life than more strenuous workout regimens.
In an interview this week, he advocated pairing light running with strength training, stretching or yoga. He defined moderate running as 10-minute miles, two to three times per week, for 1 to 3 miles at a time.
“Serious runners would scoff at that,” O’Keefe said. But “if you’re exercising for longevity, that’s totally different than training for peak fitness.”
One of his co-authors of his 2012 paper, Carl Lavie, continued his research on the topic with a 2015 study, “Effects of Running on Chronic Diseases and Cardiovascular and All-Cause Mortality.” That study concluded negative health consequences of prolonged running are possible but rare, and “the overall benefits of running far outweigh the risk for most individuals and are associated with considerable protection against chronic diseases.”
In O’Keefe’s study, he reported modest workouts “were associated with lower all-cause mortality, whereas higher mileage, faster paces, and more frequent runs were not associated with better survival.”
He was quick to point out that his research is not cause to abandon exercise or even vigorous exercise. But “long-term training for and competing in extreme endurance events may predispose to cardiovascular issues that are not seen in more moderate forms of physical activity.”
The popularity of marathons has increased in past decades. Participation rose 20-fold in the 35 years prior to 2012, according to O’Keefe’s study. Sudden cardiac death is extremely rare in marathoners, and the rate has not increased with the rise in popularity. But more deaths have occurred based on the fact that more people are participating, O’Keefe wrote.
A study published in 2013 found that from 2000 to 2010, there were 40 instances of cardiac arrest in marathons and 19 in half-marathons, out of 10.9 million registered participants. That’s just 0.54 per 100,000 participants. Cardiac arrest occurred more in men than women, and more runners survived than died. But in those who died, the average age was actually younger (39) than in those who survived (49).
“Younger age and no previous knowledge of cardiovascular risk were associated with sudden death,” the authors wrote.
O’Keefe pointed out in a video produced by St. Luke’s Mid America Heart Institute, where he works, that some people may mistakenly think that “if moderate exercise is good, then more is better. The lion’s share of benefits of exercise accrues at relatively moderate levels.”
The heart can be damaged by intense running or other forms of cardio, O’Keefe said. Long periods of extreme exercise — such as spending more than four hours a day prepping for marathons, ultra marathons, triathlons or 200-mile bike rides — can cause irritable heart muscles, irregular heartbeats and scarring in the lower chambers of the heart. The issues are mostly reversible, mending on their own after just a week, according to O’Keefe’s study.
He also reported that almost half of all sudden cardiac deaths during marathons occur in the final mile. Congenital abnormalities are sometimes the cause, he said.
He advised participation in only a few marathons or other extreme events in a lifetime, saying that amount is relatively harmless. He added: “Don’t make a career out of doing this over decades. It’s not good for the heart or blood vessels,” he said.