Wow that sounds amazing. Did you see anyone (like a doctor or a researcher) and ask for an explanation of how you can do this?
As far as I remember it wasn't always like that. Eventually at some point around my 20s I start working more and more hours and never got "break". Eventually I think my body got used to _knowing_ how many hours per night it can expect and adjusted. That or perhaps a heart attack is coming any day now at 35 (knock on the wood)