I want to summarize what I’ve learned about how to sleep well. I’ve found about a dozen changes that helped. Taken together they suggest the importance of four dimensions:
1. Healthy brain. My sleep greatly improved when I ate a lot of pork fat. (As far as I can tell, butter produced the same effect.) I wasn’t getting enough animal fat. My sleep also improved when I started eating honey at bedtime. I assume honey raised blood sugar to better levels during sleep, improving brain performance. The great importance of this, I believe, is why we evolved preferences that push us to eat strongly sweet foods, such as fruit, separately and later, i.e., dessert. Bedtime honey also caused my muscles to grow more in response to exercise — a sign of better sleep, since muscles grow during sleep. I have never measured the effect of flaxseed/flaxseed oil on my sleep but the brain benefit was so clear in other ways I’d be surprised if it didn’t improve sleep.
2. Strong oscillation. Sleep is controlled by three oscillators. The larger the amplitude of their summed output, the deeper sleep.
One oscillator — the well-known one — is sensitive to the light/dark cycle (especially blue light). It makes us active and awake during the day, inactive and asleep at night. Its amplitude depends on the amplitude of the light/dark cycle, which can be increased by sunlight or a darker bedroom, and less blue light in the evening. Vitamin D3 in the morning seems to have the same effect as sunlight, and is much more convenient.
A second oscillator is sensitive to when we eat. To ensure we’re active when food is available, it wakes us up about three hours earlier. If you usually eat at noon, for example, it will wake you up at 9 am. I realized the practical importance of this oscillator, which is well known to circadian-rhythm researchers, when I found that not eating breakfast reduced how often I woke up too early.
The third oscillator is controlled by the sight of faces — what you see during a conversation. It also controls mood, making us happy, eager, and serene during the day and unhappy, reluctant, and irritable at night . If things are working properly, most of the bad mood will happen while we are asleep. During a critical period in the morning, faces “push” this oscillator much as you push a swing. It evolved to synchronize the sleep and mood of a community so that everyone is awake, happy and eager to work at the same time. Two people cannot work together if one of them is asleep.
3. “Poison” avoidance. Alcohol and caffeine can make my sleep worse, no surprise there.
4. Muscle growth. Exercise that causes muscle growth deepens sleep, whereas aerobic exercise does not. (Aerobic exercise may make you fall asleep faster, which has never been a problem of mine.) Standing more than 8 hours during the day produced better sleep; less standing (such as 6 hours) did not. This was too hard to be practical. Later I found that standing on one leg to exhaustion had similar effects. That was practical — I still do it.
A recent editorial in the New York Times described mainstream thinking:
The brief course of sleep therapy teaches patients to establish a regular wake-up time; get out of bed during waking periods; avoid reading, watching TV or other activities in bed; and eliminate daytime napping, among other tactics. It is distinct from standard sleep advice, like avoiding coffee and strenuous exercise too close to bedtime.
I imagine the health experts of 1950 gave similar advice.
Chris Masterjohn’s comments about sleep (thanks to Stuart King for the link) illustrate what a very smart very well-informed person figured out. Like me, he stresses animal fat and the light/dark cycle (morning sunlight and dark bedroom). Unlike me, he thinks a cool room helps. I have varied room temperature and didn’t notice a difference. He mentions Vitamin B6 but I eat enough meat that I am unlikely to be deficient. He says carbs help but doesn’t narrow it down to honey at bedtime. He doesn’t mention morning faces or morning Vitamin D. Neither Chris nor I emphasize magnesium, which some people praise highly.