Sleep thread: Primates v. Humans

Millions of years ago, the common ancestor of great apes invented tree sleeping platforms (aka: the minimum-viable-bed).

Platforms allow great apes to get more deep sleep.

Other monkeys do a lot of light sleeping, since they need to listen for predators even when they're sleeping.

As the most successful great ape, humans continued iterating on the sleep platform, until we achieved ultimate sleep comfort

Comfortable sleeping isn't just a luxury; It makes us smarter.

Researchers gave orangutans pillows, blankets, and memory foam to sleep with, and found that the orangutans performed better on cognitive tests

In a study of 30 primate species, humans slept the least

Humans: 7 hours per night
Other primates: 9-15 hours per night

We are able to sleep less by sleeping efficiently: more REM sleep (the type where you dream), less NREM sleep.

There are 3 types of NREM (non-REM) sleep

Stage 1: Relaxed wakefulness
Stage 2: Asleep, but easily awakened
Stage 3: Slow-wave-sleep (SWS). You may start to dream, but your dreams will be less vivid and less memorable.

In both stage 1 and 2 non-REM sleep, you are easy to awaken.

Animals that need to stay on guard against predators do more light sleeping. If they did more deep sleep, they'd probably get eaten https://twitter.com/NaturelsMetal/status/1245778243472384001?s=20

By contrast, humans can sleep as deeply we want, since our houses and tribes and beds protect us from predators.

My current hypothesis is that humans don't need light sleep at all. Light sleep is vestigial, and in the coming millennium humans will be able to survive on less and less light sleep, and cut down our average sleep time further.

You may have heard of the "Uberman" sleep schedule where you survive off of six 20-minute naps per day, for a total of 2 hours of sleep https://www.mattressnerd.com/polyphasic-sleep/overviews/uberman-2/

The theory behind the Uberman and other polyphasic sleep schedules, is that when you deprive yourself of sleep, your body skips NREM stage 1 and 2 sleep (which are the vestigial, low-value types of sleep), and goes straight into high-value sleep: SWS (NREM stage 3) and REM.

In fact, your body skips low-value sleep after you pull an all-nighter.

When you finally sleep, the time between initially falling asleep and getting into SWS ("slow wave sleep") is halved.

Paradoxically, by restricting your sleep, your sleep becomes more efficient.

Personally, I'm skeptical of the Uberman sleep schedule or any sleep schedule that is under 4 hours of total sleep. I suspect a high-functioning human should continue getting 2 hours of REM and 2 hours of SWS.

There are other polyphasic schedules that I'm intrigued by. @Malcolm_Ocean follows a bi-phasic sleep schedule.

He gets 2 hours each of REM, SWS, and "light sleep" (stage 1 and 2 NREM).

Most people get the same amount of REM and SWS as Malcolm (2 hours each), but more light sleep.

But if light sleep *is* vestigial, the extra sleep time is unnecessary.

Individuals can sleep less than the CDC-recommended 7-8 hours, and still function at peak cognitive ability.

The key is to improve the quality of your sleep to ensure that you're maximizing REM and SWS.

A few days ago, I started the "Everyman-3" schedule, where I sleep 3.5 hours per night, and take three 20-minute naps. So in total I sleep 4.5 hours per night. https://medium.com/@drewface/30-day-polyphasic-sleep-experiment-58332f882c01

By keeping myself sleep deprived, I'm hoping my sleep becomes more efficient, limiting light sleep to the bare minimum. I'm also taking steps to improve my sleep quality, like getting blackout curtains and a face mask.

Mostly, I'm just bored during quarantine and thought it was time for an experiment