43 Can sports ever be unhealthy?

Naturally, everything can be harmful if done to excess and the same stands for sports. Actually, I’ve just read an interesting article about marathon runners. There was some research done into the heart condition of marathon runners, and the result of some MR scans showed that athletes involved in challenging sporting events like triathlons or alpine cycle races had stretched heart muscles. Although many went on to make a complete recovery after a week, some showed more permanent injuries. My personal feeling is that extreme endurance exercise probably does cause damage to the heart in some athletes. I don't believe that the human body is designed to exercise for as long as 11 hours a day, so damage to the heart is not implausible.