I do wonder if this study is confusing, at some level, cause and effect. Yes, I definitely understand the argument that people blame things on "my slowing metab

I do wonder if this study is confusing, at some level, cause and effect. Yes, I definitely understand the argument that people blame things on "my slowing metabolism", but then don't seem to notice that the requirements of middle age (e.g. full time job and especially folks with kids) can make it harder to get exercise. At the same time, I don't have kids, and while I've stayed relatively active into middle age I've definitely noticed that it takes me much longer to recover after strenuous exercise than it did when I was younger. And so it's simply harder to stay as active, because my body is basically telling me "stop!" more often. It's already well documented that testosterone levels in men begin to decline starting in your thirties at about 1% a year, so I think skepticism is in order if researchers would claim that this reduction in testosterone levels would have no impact on activity level and metabolic rate.