I lived on 36 hour days for a good year or so as well. It made being social very difficult, and was not the greatest thing for me overall, although I did get a lot of code written.

A few months ago I finally got a CPAP machine after getting a sleep study due to abnormal blood pressure patterns (my blood pressure wasn't dropping overnight on a 24 hour monitor). I can now wake up feeling alert and ready to go after 6 hours of sleep (even though I could use a little bit more); I haven't felt rested this way in the morning since more than 15 years ago in my 20s. I'm not particularly overweight, nor do I snore, so it's worth checking into if your sleep patterns tend towards abnormal.