If you haven’t been exercising regularly, but suddenly decide to hit the tennis court, you may be in for some trouble, particularly if you’re middle aged or older. “The guy who says ‘I haven’t played racket ball in 30 years, I’m going to go play with my son-in-law. I’m 60 and he’s now 30. Should be a lot of fun,’ that’s the guy who drops dead on the court because he hasn’t played in 20 or 30 years,” says Dr. Franklin. Work up to high intensity sports and activities, like snow shoveling, before diving in full throttle.