I heard somewhere that certain high performing folks only need five hours of sleep a night. I tried this for a week and it was a disaster. Damage to work. Damage to relatonships, etc.
But it did lead me to a years long experiment to discover my limits for sleep (while also struggling to understand how diet and caffeine intake interact).
I just finished a year where I aimed for 49 hours of sleep per week (5 nights of 6 hours, 2 nights of 8 hours, 1 or 2 naps of 1.5-3 hrs), and after 11+ months I started having the same problems I had from the initial 5hr/night experiment that last only a week.
So I've accepted I'm not a 35/hr a week guy. I might be a 45/hr a week guy, with precise diet/exercise/caffeine dosing, but in the meantime I'm comfortable accepting decent productivity at 55/hr a week.