Many people think this, such as workaholics who brag about needing <4 hours of sleep per night so they can be "productive" in their insanely long awake hours.
There is a set of years, maybe a decade where learning what to do and not to do is learned by spending too much time doing so.
Productivity is a relative thing. Ask folks who take a few days off from a keyboard and notice a boost in speed in typing and making more progress than they were.
The idea of having pushes to rest and recover can be normal.
But time away from the keyboard to think (or not) and be creative (or not) is as important as time at they keyboard to allow the brain to make new connections between everything it's working on.
I just turned 50 and am slowly starting to hate being sleepy. I think(?) I'm getting a restful night's sleep as I typically have, and I'm still active and eat pretty well, but damn... every time I sit down after about 3 pm I feel ready to doze off. I have so much I want to do (not necessarily work, either, but things like reading an engrossing book, watching the movie with the family, etc.), and frequently falling into a groggy state frankly sucks. I'm still experimenting with how to improve the situation.