i just finished my second 600k, so I don't have that much experience. This year, I slept 2 hours due to schedule difficulties if I had slept for 3 like I wanted. But that really seemed to make things a lot better. Last year, I did not sleep and was having trouble with dozing on the bike. My feet were hurting and so was my crotch. This year, both of those things seemed the same when I went to bed, but were much better when I got up. The saddle sores issue might have been helped last year if I had taken a shower, but letting things settle down also seemed to help.
I've been sick a lot this year so my training has suffered badly. I've been really slow. So it didn't really surprise me that I used most of the 27 hours that are allotted to ride the 400k. I didn't have any problems with sleepiness on that ride, although I did take some 2 minute naps at the controles.
There seems to be some truth to the idea that you should sleep in multiples of 90 minutes. I find that 3 hours is perfect, but 90 minutes often is enough. My randonneuring involves a lot of driving, sometimes in lieu of sleeping. I find that after a 90 minute nap I'm refreshed and don't even get close to dozing.
Last edited by unterhausen; 05-24-10 at 09:28 PM.