I totally agree that some moderate regular exercise is extremely beneficial for both mind and body. Moderate exercise has been shown to benefit the heart and movement helps keep joints supple and mobile. I somewhat disagree with exercises that can do damage though, such as lifting heavy weights, pounding the pavements stressing knee joints, and playing golf which in time can harm hip joints because of the unnatural movements involved in a powerful swing. Exercise which involves all the limbs and joints is probably best, like swimming, dancing, and playing tennis. As with a lot in life I believe that moderation is the key... We are anatomically and physically much the same as early man, the hunter gatherer, who would walk for miles in a day or run for short bursts and then take a break..
You put it so correctly!
We see so many people exaggerting just to show off. Just visit a gym when a bunch of macho men are training, to me it's just too much energy wasted to wear your body off. Moderation is everything and always adjust your training programme to your body's needs and capabilities. That way you gain physical and mental well-being. It's like my Greek ancestors said: A healthy mind in a healthy body (Νους υγιης εν σωματι υγιη)