Now that fall's officially here, it's time to get down to business. But while it’s important to work hard in the studio, make sure you know when to take a break. A recent study in the Mayo Clinic Proceedings found that exercise, like anything else, can be harmful when over done. According to Dr. James O’Keefe of the Mid America Heart Institute of St. Luke’s Hospital, when an athlete exercises intensely for excessive amounts of time, the heart muscle begins to tear and releases troponin, the same enzyme that signals damage during a heart attack. Although extreme exercise doesn’t have any immediate effects, all that abuse piles up and can lead to long-term damage. So before you push yourself too far for too long, remember: Everything in moderation.