From The Desk Of Clarence Bass
Cooper Institute Data Provides Mixed Message on Extreme Exercise
More Coronary Calcium--Lower Mortality
We were wrapping up this month’s Update when a Cooper Institute bulletin arrived about a new study on the possible dangers of extreme exercise, an issue we wrote about in our January Update. It’s an eye-opener you’ll want to know about. The study was published January 30, 2019, in JAMA Cardiology.
Do the health benefits of exercise plateau before fitness peaks? The new study suggests that may be the case.
Six Miles Every Day!
Dr. Laura DeFina, CEO and Chief Science Officer for The Cooper Institute, and colleagues from the Cooper Clinic and UT Southwestern Medical Center observed 21,758 healthy middle-aged men who were examined at the Cooper Clinic between 1998 and 2013. The men had undergone coronary artery calcium scanning and were divided into three categories based on their physical activity level—and then followed for 10 years.
The highest activity level was equivalent to running six miles every day at a 10-minute-per mile pace. An hour seven days a week; a total of 42 miles.
There were two key findings. The men in the highest physical activity category were more likely to have high levels of arterial calcification (mean 807 units) than those in the lowest activity group. The highly active men were nevertheless significantly less likely to die than those in the low activity group.
The researchers concluded: “This study suggests there is evidence that high levels of physical activity…are associated with prevalent CAC but are not associated with increased all-cause or CVD mortality after a decade of follow-up, even in the presence of clinically significant CAC levels.”
“Certainly, these highly active people should review their cardiovascular disease risk with their primary care doctor or cardiologist, but there is no reason to think they can’t continue exercising at high levels,” Dr. DeFina said in The Cooper Institute bulletin.
“The question has never been whether exercise is good for you, but whether extreme exercise is bad for you,” added senior researcher Benjamin D. Levine, MD, director of the Institute for Exercise and Environmental Medicine, a collaboration of UT Southwestern Medical Center and Texas Health Presbyterian Hospital Dallas. “For the past decade or so, there’s been increasing concern that high-volume, high-intensity exercise could injure the heart. We found that high volumes of exercise are safe, even when coronary calcium levels are high.”
The Cooper Institute bulletin ended: “It is safe to say that exercise is still the best preventive medicine for living Well. Into the Future.”
Dr. DeFina told NY Times health reporter Gretchen Reynolds that the outwardly unlikely combination of plaque buildup and low mortality probably occurs because extreme exercise creates a unique type of plaque. “There is some evidence that the plaques” in highly active people “are denser and more stable” than those in sedentary people making them less likely to break free and cause a heart attack.
Scientists are also unsure, she added, how strenuous exercise might prompt the buildup of plaque, while others are unaffected no matter how much they exercise.
“In the meantime,” she told Gretchen, “middle-aged runners and other endurance athletes should pay attention to any heart-related symptoms, such as chest pain or shortness of breath, and talk to their doctors about the desirability of a heart scan.”
Dr. Levine talked to US NEWS Health Day reporter Dennis Thompson about the importance of finding “a meaningful amount of exercise across your lifespan.”
While extreme amounts of exercise don’t appear to harm your heart, you don’t need to do that much exercise to keep yourself healthy, he observed.
“The biggest bang for your buck comes with the conversion from a sedentary to an active lifestyle,” Levine told Mr. Thompson. “Most of the benefit for cardiovascular mortality tends to plateau at about the three- to five-hour-a-week mark.”
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Dr. Cooper’s long standing observation that people running more than 15 miles a week are doing it for reasons other than health seems to be gaining credibility.
See “My Take” on sensible levels of exercise in my earlier article on Overdoing a Good Thing:
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Copyright © 2019 Clarence and Carol Bass. All rights reserved.