Z3: First 'short night' experiment

The first full night with the Zeo confirmed the expected typical sleeping pattern: during the first half of the night, there is little more than light sleep and waking periods. I decided then to do an experiment, and see what would happen if I'd skip that first half of the night. That meant going to sleep around 3 am. This sounded a bit daunting at first, but then again I not infrequently go to bed after 1 am.

The evening of March 21st I felt wakeful (and not tired) enough to go ahead with this plan. I simply went through the usual evening routine, except when it was time to go to sleep... I just carried on. Since the point was to test the ability to stay awake, I opted not to engage in anything too intellectually demanding. It ended up being a rather useful time: I started this blog, wrote the first three entries (with very minimal editing - it's almost 'flow of mind' writing), watched a TED talk, did a set of 15 push-ups, watched some stuff on Netflix, listened to music off youtube while reading and catching up on several backlogged RSS feeds.

Towards 3 am I wrapped the extended day up, put the Zeo on and went to sleep. I was hoping to observe: 1) a very short time to fall asleep, 2) relatively little light sleep, 3) a much higher proportion of REM.

Three and a half hours later, the alarm clock sounded. I woke up, noticed the headband was still on, recalled the plan, and with great interest and curiosity turned to the Zeo bedside console to look at the graph, and saw (a black and white version of) the following:

Even though I wasn't feeling dazed at all, it took me a little while to figure it out. Apparently, the Zeo recorded just the first hour of sleep, most of which was again light sleep, and then... it quit, for no obvious reason. I didn't take the headband off, it was on when I woke up. The three marks on my forehead were there. So why did it stop recording after exactly one hour? No idea.

The first expectation checked out fine: it apparently took me just 5 minutes to fall asleep. The second expectation didn't pan out for the time of recording (just 2 minutes in REM, 1 minute in deep sleep). As for the third, I have no idea, beyond the fact that I remembered plenty of quite vivid dream activity. Who knows, perhaps a big fraction of the remaining 2.5 hours of sleep were spent in REM, but the Zeo failed to record it, and I'm left in the dark.

So after sleeping half a night, what was my day like? In short, and not surprisingly, it was low energy and sleepy. On the other hand, it was not extraordinarily so - it was within the range of what I experience with "a full night" (except again, not infrequently my nights are short). The day seemed to pass rather quickly and wasn't very productive (which can also be explained by the meetings).

Of course, for it to be a reasonable sleep pattern I had to plan for one or more siestas (which I never do). I did the calculation for the simplest possible pattern: biphasic, with a siesta diametrically opposite the 'core' night sleep. That would be, for example, 16:30-17:00 for a half hour siesta.

I had coffee as usual around 8:30. I went for a quick rest from 11:10-11:30, but didn't sleep. Second coffee at 13:30 after lunch. Towards the end of the workday I felt tired enough, and the planned siesta sounded like a good prospect. I dozed off between 16:30-17:00 as intended. Took a while to fall asleep, but it happened, and when the alarm sounded, I felt much refreshed. The commute back home (walk+bus) helped wake me up further. Around 20:00 I had a third cup of coffee, and also did six sets of 15 push-ups without any hardship. At that point, it looked like the first day of this experiment had been successful enough (except for the technological failure), and I was up for trying a second day.