There are two plausible ways to cut sleep duration without harming cognition: increasing the proportion of slow wave sleep that is spent in deep sleep and reducing REM sleep.
Slow wave sleep is needed for synaptic homeostasis (e.g. see https://www.sciencedirect.com/science/article/abs/pii/S1087079205000420). There are evolutionary trade-offs between time spent awake, time spent in light sleep, and time spent in deep sleep. Deep sleep is more restorative than light sleep but an animal is more likely to be awakened from predators in deep sleep. Humans sleep less than other primates but spend more time in deep sleep than other primates—maybe because our ancestors took turns to stay awake and watch for predators at night?
I’m not so sure what the function of REM sleep is. Maybe something something emotion learning something something? There are cases of people on antidepressants going months with no REM sleep. There are also cases of people on antidepressants who say they have no emotions so I doubt that it’s possible to cut REM sleep without side effects.
I had a Zeo sleep monitor and I noticed that I had more REM sleep when doing hard intellectual work or deliberate practice, or after emotionally intense experiences. I had more deep sleep when exercising hard e.g. sprints or resistance training. This suggests to me that these forms of sleep are respectively associated with learning and body repair.
I also notice that I can learn a lot faster when I have naps and/or ample sleep. And that I recover from hard exercise more quickly.
OK this is all a bit uncertain but not just vacuous speculation.
I would like to see some evidence that orexin does not detract from these alleged effects before using it. Edit—the EA article does provide some evidence for this.
The linked article speaks about a hypothesis and the abstract does not use language indicating certainty. In its text, it speaks about how the hypothesis might be validated which is basically an admission that it’s not validated.
Deep sleep and REM sleep are not the only sleep phases. We spent half of our sleep in light sleep.
There are two plausible ways to cut sleep duration without harming cognition: increasing the proportion of slow wave sleep that is spent in deep sleep and reducing REM sleep.
Slow wave sleep is needed for synaptic homeostasis (e.g. see https://www.sciencedirect.com/science/article/abs/pii/S1087079205000420). There are evolutionary trade-offs between time spent awake, time spent in light sleep, and time spent in deep sleep. Deep sleep is more restorative than light sleep but an animal is more likely to be awakened from predators in deep sleep. Humans sleep less than other primates but spend more time in deep sleep than other primates—maybe because our ancestors took turns to stay awake and watch for predators at night?
I’m not so sure what the function of REM sleep is. Maybe something something emotion learning something something? There are cases of people on antidepressants going months with no REM sleep. There are also cases of people on antidepressants who say they have no emotions so I doubt that it’s possible to cut REM sleep without side effects.
>Function of REM sleep
https://en.wikipedia.org/wiki/Rapid_eye_movement_sleep#Deprivation_effects
I had a Zeo sleep monitor and I noticed that I had more REM sleep when doing hard intellectual work or deliberate practice, or after emotionally intense experiences. I had more deep sleep when exercising hard e.g. sprints or resistance training. This suggests to me that these forms of sleep are respectively associated with learning and body repair.
I also notice that I can learn a lot faster when I have naps and/or ample sleep. And that I recover from hard exercise more quickly.
OK this is all a bit uncertain but not just vacuous speculation.
I would like to see some evidence that orexin does not detract from these alleged effects before using it. Edit—the EA article does provide some evidence for this.
The linked article speaks about a hypothesis and the abstract does not use language indicating certainty. In its text, it speaks about how the hypothesis might be validated which is basically an admission that it’s not validated.
Deep sleep and REM sleep are not the only sleep phases. We spent half of our sleep in light sleep.