Of course you can slow down the process through living healthier. My point is: when you are young, you don't need to. You can go weeks having little sleep and be fine. You don't need to actively pursue a healthy lifestyle in order to avoid feeling drained. Your body reaches the peak in your 20s. After that it's a progressive decline.

In your 30s, no matter what you do, your ability to recover starts to decline and you can no longer do stuff consequences free like before.

You say if yourself: as long as you get enough sleep most of the time, you can pull an all nighter and feel fine. Pull 3 in a row and throw in some drinking, and you'll note a sharp difference between 25 year old you and 35 year old you.

Genetics plays a huge role in this. Some people win the lottery. However, by your 40s you realize that some activities might simply be off limits. Repetitive back injuries from lifting too vigorously mean that you have to cut back on deadlifts. You get dehydrated more easily and the symptoms are worse. You need to watch your ankle after having twisted it too many times during football.

You have to accept it and move on. Some magic you had is lost, but you can usually replace it with other magic. You can't play 12h with your friends every day, but now you can afford a nice car for example, etc...

You can't go clubbing 5 days a row, but you have the focus to train for a marathon and finish it.

My post was about recognizing that the circumstances that make certain things possible when we are young simply disappear. Accept this and move on, there are other things that one can do.