Exercise is good for you but some people worry there can be too much of a good thing, especially for middle-aged athletes. Extreme running and high-endurance exercise were a concern to some doctors but a study using coronary calcium scanning, an imaging test that helps physicians classify patients without cardiac symptoms as low, intermediate, or high risk for heart attack, show the fear is unfounded.
Coronary calcium scanning represents how much calcium (and thus cholesterol deposits) has accumulated in the blood vessels that supply the heart. It can help physicians determine the need for medication, lifestyle modification, and other risk-reducing measures because it 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.
But it is a risk factor, not a disease in itself, and that is why the study finding the majority of high-intensity athletes had low levels of coronary calcium, though their odds of having higher levels were 11 percent greater than men who exercised less, will be good for the exercise debate. Most importantly, the researchers found that
Higher cholesterol did not raise the high-intensity athletes' risk for cardiovascular or all-cause mortality
The data from the Cooper Center Longitudinal Study. A total of 21,758 generally healthy men ages 40 to 80 and without cardiovascular disease were followed for mortality between 1998 and 2013. The athletes, a majority of them in middle age, reported their physical activity levels and underwent coronary calcium scanning. Most were predominantly runners, but some were cyclists, swimmers, or rowers. A subgroup of athletes trained in three of these sports.
High-volume, high-intensity exercise was defined in this study as at least five to six hours per week at a pace of 10 minutes per mile. The average amount of high-intensity exercise in this group was eight hours per week.
Women were excluded from the paper because they would have been a confounder, as their mortality rates are lower than for men.
The benefits of exercise far outweigh the minor risk of having a little more coronary calcium
"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," says Dr. Benjamin Levine Professor in Exercise Sciences at UT Southwestern.