Exercise, Heart | featured news

Could exercise actually be bad for some healthy people? A well-known group of researchers, including one who helped write the scientific paper justifying national guidelines that promote exercise for all, say the answer may be a qualified yes.

Competitors dive into the water at the start of the Hy-Vee Triathlon on Sunday, June 13, 2010, in West Des Moines, Iowa. On Sunday during the Nautica New York City Triathlon, two competitors experienced problems during the swim phase of the race, and later died.

Exercising or having sex roughly triples a person's risk of heart attack in the hours immediately afterward, especially if the person does those activities infrequently, according to a new analysis in the Journal of the American Medical Association.