Ivan Kurmyshov/ShutterstockThe benefits of exercise are well proven. Working out accelerates weight loss, boosts mood, lowers the risk of illness, helps prevent osteoporosis, lowers blood pressure, reduces chronic pain, and helps increase libido. But can you exercise too much?
According to a new study led by researchers at the University of Illinois at Chicago and Kaiser Permanente, there may be serious dangers of excessive exercise for some people. For the longitudinal, cohort CARDIA study, the team examined the physical activity ranges of 3,175 black and white participants who self-reported physical activity during at least three of eight follow-up examinations over 25 years, from 1985 through 2011.
The results, published in Mayo Clinic Proceedings, show that white men who exercise the most per week are 86 percent more likely to have a buildup of plaque in their heart arteries by middle age, compared to people who exercise at low levels.
Participants were split into three groups, based on their physical activity patterns. Group one exercised below the U.S. Department of Health and Human Services (HHS) national guidelines (less than 150 minutes per week), group two met the national guidelines (150 minutes per week), and group three exercised three times above the national guidelines (more than 450 minutes per week).
Researchers looked for the presence of coronary artery calcification, or CAC, a clinical measure of the accumulation of calcium and plaque in the arteries of the heart. CAC is a warning sign that a patient may be at risk for developing heart disease, the leading cause of death for both men and women in the U.S., according to the U.S. Centers for Disease Control and Prevention. (Watch out for these signs of an unhealthy heart.)
“We expected to see that higher levels of physical activity over time would be associated with lower levels of CAC,” says Deepika Laddu, assistant professor of physical therapy in the UIC College of Applied Health Sciences, as reported on ScienceDaily.
But the study revealed the opposite: group three participants (the ones who exercised the most) were 27 percent more likely than those in group one (those who exercised the least) to develop CAC by middle age (between 43 and 55 years old).
Interestingly, white men were found to be the highest risk group—specifically, those who exercised the most were 86 percent more likely to have CAC. There was no higher odds of CAC for black participants who exercised at this level, and while there was a similar trend for white women, it was not statistically significant.
“Because the study results show a significantly different level of risk between black and white participants based on long-term exercise trajectories, the data provides rationale for further investigation, especially by race, into the other biological mechanisms for CAC risk in people with very high levels of physical activity,” says Laddu.
The researchers stress that this type of plaque buildup over time may be a more stable kind, and less likely to rupture and cause cardiac arrest, but this was not examined in the study. They don’t reveal how much exercise is too much and point out that the results should not encourage anyone—white man or otherwise—to stop exercising. Want to add years to your life? Check out the best science-based anti-aging workout.