I'm talking about athletes- not just people who exercise. I mean, you look at marathon runners; pro cyclists; football players, etc. Seems like many barely make it past their 60's.

And I am not aware of any studies on the effects of exercise and health, which take people's genetics or established metabolism into account. Sure, they may say something like "69% of those studied lived an average of 3.7 years longer if they stuck a box of spaghetti on top of their head while hopping up and down on one foot"- but maybe it's because that 69% possessed traits which were conducive to the benefits of such an activity- whereas maybe that same activity was non-beneficial or even harmful to those in the other 31% group, because it was counterproductive to their established traits- but it's just that people with such traits may be in a minority- whether in the general population, or just in the study- the fact remains, that leaving out vital data makes all such studies largely irrelevant. Someone with a slow metabolism may actually be doing themselves harm by doing the same amount of exercise recommended for "the average person"- or conversely, the average person may not be getting enough exercise if the subjects who were being studied were in-fact not so average, but such was noit realized because the attributes which made them not so average, were not even an item being referenced.

This is exactly why we can have "scientists" saying that eggs and salt and butter are b ad for the last 40 years; and that trans-fats are good.....and then all of a sudden, the pendulum swings the other way- and now they are saying the diametric opposite is true. Assuming none of the conclusions are based on out-right fraud or some other agenda, the only other thing which can account for the studies of the very same things giving diametrically opposite results, is that important parameters were were ignored.