The data for extreme endurance athletes such as marathoners is mixed. It&#x27;s very possible that racing at long distances is a risk factor.<p>The data on intense weight-lifting on the other hand is much more conclusive. Heart enargement, aortic dissection and a host of other heart related risks are sharply higher for extreme weightlifters.<p>Lifting a couple of days a week and doing cardio 3-4 days a week and not going completely nuts with either is probably the safest. But sometimes it&#x27;s fun to go nuts and shoot for a goal. In the big scheme of things, there are a lot worse hobbies to have.