I too, get minimal sleep as well. Its just how I've always been. Life will not allow more! I'll get between 4 and 5 hours (if I'm lucky) due to a new baby, kids, and work. I've always been a 5hr a night sleeper though. I've just always functioned on 5 hrs. Once every other week or so, if training catches up with me, I'll get more, if I can. I'll train 20-22 hrs in season, and go 10hr in IM distance. I find that really utilizing the taper is the most important part. That, and not letting your immune system drop.
I work early. Thats how I start my day. I always assumed others were not getting a full 8 as well! Others who get up at 4am and go for a swim, and THEN go to work, THEN get a run or ride in later in the day or whatever they do, are they now going to bed at 8pm every night?!? My 9 year old doesn't even go to bed at 8pm! Am I supposed to cash out before my child does every night?!? I guess for non-parents its easier? My grandpa used to say "its the highlander in us." (I'm Scottish) Back in the day, you'd sleep lightly, and only a few hours a night, otherwise you'd get your horse stolen in the middle of the night or something... Worked for William Wallace, right?!?! I guess some are just wired differently than others! That said... I imagine if I got more sleep, I'd see better results!!!

Best of luck to ya!


-Edit.... Rereading the TITLE of the thread... I get 5 hrs of sleep a night... If it starts shifting to 4 hrs... Then I REALLY feel it. Its a fine line. And for me, anything less than 5hrs I start feeling right away!