Is running really good for the heart?

But, recent news stories about runners suffering sudden cardiac arrest (SCA) and other heart-related complications mid-race might leave some wondering if there may actually be a risk to running.

Just weeks ago ABC News reported about a man who had an SCA while running the Key West half marathon, The Telegraph shared news of a runner in the London marathon who collapsed three miles before the finish line in April 2016, and Philadelphia Magazine reported in 2015 that two athletes suffered an SCA during the Broad Street Run.

"Running, or any kind high-intensity exercise, puts a strain on the heart muscle, as it does on lung tissue, and leg and arm muscles," said Neel Chokshi, MD, an assistant professor of Clinical Cardiovascular Medicine, and medical director of the Penn Sports Cardiology and Fitness Program. "While evidence suggests an increased risk of cardiac events during high intensity exercise, the overall likelihood of such events is ultimately very, very low. There is more far research to support running and exercise as a benefit to heart health, rather than a detriment."

The World Health Organization (WHO) suggest that adults ages 18 to 64 do at least 150 minutes of a moderate exercise or at least 75 minutes of high-intensity physical activity each week. Guidelines also recommend adding muscle strengthening exercises into the routine two or more days per week.

Based on these recommendations, a casual runner could log eight miles per week at about a nine-minute mile pace. But what about someone training for something more rigorous, like a marathon, or triathlon? Is there more risk for competitive athletes, who run say 20 to 40 miles a week -- or 210 to 300 minutes of vigorous exercise -- effectively tripling or quadrupling this recommendation?

"It's important to understand that the likelihood of cardiac events is greatest in those individuals who have a low baseline level of physical activity and suddenly jump into moderate to high intensity exercise," Chokshi said. "So, as long as you train in a progressive manner, gradually increasing mileage, pace of a run, or amount and type of exercise, and you listen to your body, your heart and lungs will adapt at the same rate. This will allow you to continue your training while minimizing risk of injury to both your heart and other muscles."

And this same advice applies to anyone looking incorporate more exercise into their routine. Everyone should be aware of the possible risks and listen to their bodies, but the most important thing is engaging in some level of activity each day or week -- which has been shown to have immense heart and overall health benefits.

A recent study published in JAMA Internal Medicine found that even those who exercised for fewer than the recommended time (150 minutes of moderate or 75 minutes of vigorous exercise per week) showed a decrease in risk of death, when compared to those who had little to no physical activity each day. More, researchers concluded that any amount of physical activity lowered risk of death, specifically from heart disease, by approximately 40 percent, as compared to those who led a sedentary lifestyle.

In an Associated Press article about the study, Daniel Rader, MD, chair of Genetics and director of Penn's Preventive Cardiovascular Program, said, "People who exercise more regularly report that they feel like they have a better quality of life," among other benefits. However, he added, "even if you only have time to do something once a week, this study would suggest it's still worth doing."

This seems promising for those who find 150 minutes of exercising to be daunting, for those who are coming back from an injury, looking to take the first step toward leading a more active lifestyle. The main message seems to be 'anything is better than nothing.' But for some, the question of how to minimize any risk from exercise still remains.

Chokshi said, "in general, most individuals who increase their workouts gradually and feel well while doing so are at low risk and require no medical evaluation. But, patients with pre-existing heart conditions or those who experience heart-related symptoms such as chest pain, shortness of breath or palpitations during exercise, may be at increased risk during exertion. This group should work in closely with their physician to understand risk factors, determine if any pre-exercise testing is needed, and to create an exercise regime that can help reduce risk of an exercise-induced cardiac event, while still maintaining a healthy lifestyle."

But if most people have little to no risk for a cardiac event while exercising, why has there been so much buzz linking exercise to SCA?

As a 2016 paper from the American College of Cardiology's (ACC's) Sports and Exercise Cardiology Leadership Council points out, "the public media has embraced the idea that exercise may harm the heart and disseminated this message, thereby diverting attention away from the benefits of exercise as a potent intervention for the primary and secondary prevention of heart disease."

So perhaps we don't need to cut back on exercise, but instead need to read past the headlines to understand what is really good (or bad) for our hearts. For Chokshi, the recommendation to exercise as a preventative measure will continue, as will his focus on clinical and research efforts evaluating the effects of rigorous, and regular, exercise on the heart.