Well, there was a time I would push myself no matter what - but I have learned, the hard way (seems this is how I normally learn )

Back when I was a young 40, I suffered a collapse that lasted nearly 5 years due to working 80+ hour days in software, for years, without allowing time for recovery. Since that time, I have never had the energy I once did. Now, perish the thought, we do get older, and recover more slowly. Perhaps I have chronic fatigue syndrome, or as my wife says, I am just normal now.

One quote I liked I read once was someone was trying to build back from an injury and pushing himself and his heart rate. He asked the doctor what is the "record", the doctor responded "zero heart rate".

The point being, you push too far, and the consequences might not be so easy to recover from.

I like that phrase, "proving to yourself you can relax and enjoy yourself..." Yep, still trying to figure that one out.