I'll have to differ on this. I train really hard a LOT. Why? Because I like to, and I enjoy keeping up with the youngsters around here. I generally end up taking one day a week off, and occasionally two days but this is because life intrudes on my riding. My legs are sore all the time but it's a sort of pleasant soreness which reminds me of the work I've been doing. I've been carrying this load for years BTW. I don't really think our bodies in general are that much different than they were long ago. It's just that many of us choose not to work that hard. No problem there, but some of us do. It hasn't hurt me yet