Wednesday 12 September 2012 23:33 to 05:14

(5:40 hours)

I think I probably didn't need the extra sleep last night in the end. I woke up naturally at 4:30am, and went back to sleep, and then woke up just after 5 and got up.

The good thing about waking up naturally is that there is absolutely no tiredness at all!

The fact that I first woke up naturally after 5 hours (300 minutes) suggests that I had 3 full sleep cycles, and that my cycles are about 100 minutes long. It might be worth permanently lengthening my core to 5 hours in the long run.