Is it fair to say that the intense physical exertion you engaged in might have made both these conditions worse or made them occur earlier in life than they might have otherwise? I am not trying to place blame; just emphasizing your point that exercise is not always a slam-dunk for good health. Certainly not extreme intensity exercise.
No, it is not “fair to say” that my healthy lifestyle caused these conditions to occur earlier than they might otherwise. Quite the opposite. Both my orthopedic doctor, who did my knees and my cardiac surgeon, who did my heat surgery, told me my family history played the biggest part in me having the same problems as my parents. By exercising and taking care of myself my whole adult life, they told me I managed to delay the onset of the problems, rather than them occurring sooner.
My dad had both of his knees replaced at age 60 and he never ran a day in his life or exercised. He started having heart problems in his 60’s too, as did his dad before him. Lifestyle has little to do with some medical problems. My wife is a thin, healthy 105 lbs and is in great physical shape. She eats a healthy diet like a bird but has high cholesterol. Why? Not because of her lifestyle and eating habits but because her whole family has high cholesterol. It runs in her family. Some of these conditions are unavoidable. They’re caused from the genes you’re born with. Some folks are just blessed with better genes than others.