Extreme exercise does not raise heart disease risk, Texas researchers say

photoPhoto: UT Southwestern

Exercise is good for us. Everyone knows that. But is there such a thing as too much exercise?

A new study says no, at least as far as heart health goes. Researchers at the Institute for Exercise and Environmental Medicine studied the amount of calcium build-up in the blood vessels of athletes hoping to learn whether extreme athletes were at greater risk of heart disease than more moderate exercisers.

Extreme exercise was defined as at least five to six hours per week at a pace of 10 minutes per mile.

“The question has never been whether exercise is good for you, but whether extreme exercise is bad for you. 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,” said Dr. Benjamin Levine, who led the study published in JAMA Cardiology.


The study looked at 21,758 men with varying levels of physical activity. It found that the presence of elevated levels of coronary artery calcification was more prevalent among highly active men. But there was no increase in all-cause or cardiovascular disease death in the highly active group when compared with those who were less active.

However, Levine cautions against using the protective effect of exercise to excuse poor lifestyle habits.

“You cannot overcome a lifetime of bad behaviors – smoking, high cholesterol, hypertension – just from doing high levels of physical activity, so don’t use that as a magical cure,” said Levine in a news release.

Levine also recommends caution when starting a new training program. “If you want to train for a marathon, you have to have a long-range plan to build up slowly before you achieve those volumes and intensity of exercise.”

No increased risk

“The known benefits of regular physical activity in the general population include decreased mortality, heart disease, diabetes, and many other medical conditions which reminds us how important it is participate in regular physical activity as recommended by the 2018 Physical Activity Guidelines,” said Dr. Laura DeFina, Chief Scientific Officer of The Cooper Institute and co-author of the study.

“The current study shows no increased risk of mortality in high-volume exercisers who have coronary artery calcium. Certainly, these high-volume exercisers should review their cardiovascular disease risk with their primary care doctor or cardiologists and the study results provide helpful clinical guidance,” DeFina said.

“The most important take-home message for the exercising public is that high volumes of exercise are safe. The benefits of exercise far outweigh the minor risk of having a little more coronary calcium,” Levine said.

About coronary calcium

Coronary calcium is a footprint of atherosclerosis, a disease in which plaque builds up in the arteries and gives rise to heart attack and stroke. When coronary calcium is detected in the heart, the clogging process within the blood vessels has begun.

The majority of high-intensity athletes in the study had low levels of coronary calcium, though their odds of having higher levels were 11 percent greater than men who exercised less. Most importantly, the researchers found that higher calcium scores did not raise the high-intensity athletes’ risk for cardiovascular or all-cause mortality.

Women were not included in the study as their mortality rates are lower than for men.

 

About the Author

Truman Lewis
Truman has been a bureau chief and correspondent in D.C., Los Angeles, Phoenix and elsewhere, reporting for radio, television, print and news services, for more than 30 years. Most recently, he has reported extensively on health and consumer issues for ConsumerAffairs.com and FairfaxNews.com.