Last night I slept great. I woke up feeling very rested. I can remember only three situations when I woke up feeling more refreshed. (a) On a certain camping trip. (b) When I was on my feet for ten hours. (c) After eating a lot of pork fat. I cannot simulate camping trips, and standing ten hours/day was very hard. The pork-fat effect was repeatable, in the sense that I slept better after eating pork fat, but I never ate that much pork fat again. It was too much.
Why did I sleep so well? I can think of several possible reasons.
1. Random noise. Let’s say there are 20 factors that affect my sleep and they just happened to all line up in a good direction.
Another set of possible reasons derive from what was unusual about yesterday. I can think of five things:
2. I had yogurt and blueberries and honey about 6:30 pm. (In addition to 1 tablespoon honey at bedtime.)
3. I forgot to hang a blackout curtain that darkens my bedroom. Usually I hang two. Last night, by mistake, only one.
4. I started eating dark chocolate daily two days ago. Maybe the good stuff in it (the flavones) accumulates in the brain so that the good effects get larger day by day.
5. I watched faces in the morning a half-hour later than usual. Usually I start watching them at 6:00 am. Yesterday I started at 6:30 am. I had forgotten about this difference until I looked at my records.
6. I switched to a new brand of honey (from a German brand to a Canadian one).
#1 is unlikely. #2 vaguely corresponds to the idea that honey helps us sleep because it supplies energy. Maybe honey at 6:30 fills up the liver (with glycogen) and honey at bedtime goes into the blood. But I’ve eaten plenty of meals at 6:30 without any obvious effect. Maybe they were too low-carb. I don’t know if making my room very very dark (two curtains) is better than making my room dark (one curtain) but there is no obvious reason making my bedroom less dark would improve sleep (#3). I have never heard anyone say chocolate (#4) improved their sleep. Morning faces did improve sleep but the mood improvement was much more obvious (#5). I’ve tried several brands of honey; there was no obvious difference between them, arguing against #6.
As the day wore on I found myself in a good mood but not a great mood, arguing against #5.
I’d say #2 is the most plausible, the rest less plausible, with #1 the least plausible. But I will test all of them.
More (a day later) I did #3 (only one curtain), #4 (chocolate), #5 (later faces), and #6 (new honey) again. I did not sleep exceptionally well. That makes #1 and #2 more plausible.