At 7:45 a.m. each weekday, while most of his peers at Naperville Central High School in Naperville, Ill., are sitting in class and groggy with sleep, 15-year-old Matt Bray is running sprints, jumping ...

Moderate exercise is good for the heart, but high levels of exercise can cause a phenomenon known as "athletic heart," which comes with risks. When you purchase through links on our site, we may earn ...

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William Cornwell does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond ...

Editor’s Note: This is one of the most-read leadership articles of 2014. Click here to see the full list. “Yes, yes, I know all about it, that’s the thing with the endorphins, that makes you feel good ...