The general assumption among health experts and exercise advocates is that exercise is if good for heart health, then more exercise is better. But now comes research from the University of Illinois at Chicago and Kaiser Permanente suggesting that a great deal of active exercise may actually increase the risk of heart disease. A University of Illinois news release reports that researchers at the school have found that white men who exercise at high levels are 86 percent more likely than people who exercise at low levels to experience a buildup of plaque in the heart arteries by middle age. The researchers looked at 25 years worth of reported physical activity of 3,175 black and white men in the community-based, longitudinal cohort CARDIA study, then assessed the presence of coronary artery calcification, or CAC, a warning sign to doctors that a patient may be at risk for developing heart disease. Researchers categorized participants into three groups: those who exercised below the national guidelines (less than 150 minutes a week); those who met the national guidelines for exercise (150 minutes a week), and those who exercised three-times above the national guidelines (more than 450 minutes a week).
“We expected to see that higher levels of physical activity over time would be associated with lower levels of CAC,†said Deepika Laddu, assistant professor of physical therapy in the UIC College of Applied Health Sciences.
Instead, Laddu and her colleagues found that participants in trajectory group three, or those who exercised the most, were 27 percent more likely than those in trajectory group one to develop CAC by middle age. Laddu noted that the study results show a significantly different level of risk between black and white participants.