The difference between someone recovering after a drain or severe injury or setback, and someone being debilitated because of that in the long term, leading to what is called “aging” these days, is gene repair.
When I was little, I grew up with a lot of bikers in the extended foster family, church, neighborhood. One of the most popular bikes was the Royal Enfield “Bullet” bike. It had a huge exhaust pipe that used to get really really hot.
You see that big exhaust pipe, Ed? Imagine that hot enough to fry eggs on.