“Researchers analyzed the workout patterns and health of 3,175 black and white men and women aged 18 to 30 over a span of 25 years. The subjects were participants in the Coronary Artery Risk Development in Young Adults study, in which they self-reported their health and exercise in eight follow-up examinations over a quarter of a century. Subjects were also given heart scans so researchers could look at the state of their arteries.
The findings suggested that white men who work out around 8 hours a week or more have nearly double the chance of suffering from heart disease than those who exercised less than two-and-a-half hours a week.”
http://www.sacbee.com/news/nation-world/national/article179463911.ht