When I wore a younger mans clothes, I experienced this often and after a while was unhappy without more adrenaline. Nowadays they call these people "adrenaline junkies" and it is very similar to addiction to chemicals. The highest highs come in competition that also includes life endangering acts. Mine was downhill ski racing and the like. That was seasonal so I had to find replacements in the off season. This lead to dangerous and risky behavior.
After children I did it with a suit on. Taking way too many risks and putting my neck way too far out there. It was not until my forties that I really got over it.
The down time is very much like depression. Except that during the down time there is the effort that goes into doing it again.
In fact adrenaline is a drug. Just one supplied by the body. When it wears off there is a huge let down.