Basically the thesis of that Peter Attia book is that, past the basic "stop smoking don't be fat get some sleep" stuff you should be doing for your health, the thing that takes a lot of people down (or severely degrades their quality of life in their final years rendering them useuless and contributing to other factors leading up to their death) is an injury that they never bounce back from. It's hard to build muscle and recover as we age, most of us are fat and weak, you toddle along for a long time and then have a bad fall and get laid up for a few months (losing hard to regain muscle) and never regain your quality of life or your physical health.
Anyways, that piqued my interest because while I don't care that much about having a body builders body or being able to do feats of strength, I want to be able to get through the airport and roll out of bed and walk at a brisk pace and etc etc etc deep into old age. Interesting to see the observations here of that thing he talks about - having to fight to regain strength after injury.