There are quite a lot of people (around 3% of the population) with an abnormality (or duplicate) of the ABCC9 gene who are programmed to run on 6 hours a day, but they usually carry a higher risk of heart disease and other nasty stuff.
In my case (which is apparently ludicrously rare) Its a mutation of the hDEC2 Transcription facilitator linked to the BMAL1 gene.
No side effects. I have to get medicals every year and I'm stupidly healthy despite my shitty lifestyle and morbid fear of salads.
Haven't had a flu or anything for years.
Also, when asked, random girls guess my age at around 27, which I'm quite ok with... :P So I guess I don't LOOK tired either.
I'll go to bed at about 11 tonight, and be up at 3am to start work. Sometimes I grab a 30min disco siesta after lunch if I have time.