Human Sleep Evolution

For those landing on this comment, some reference: http://slumberwise.com/science/your-ancestors-didnt-sleep-li...

"The evolution of sleep is inevitable" https://arxiv.org/abs/1610.00293

We don't actually know if 1/3rd downtime is a requirement. For most of our evolutionary history, it has not been economical to remain awake at night, so our intense sleep drive may actually be driven primarily by conservation of energy (since energy has been a major engineering constraint for all of our evolutionary history minus the last several hundred years or so). If that's the case, then with other processes may have evolved to fit themselves into our sleeping time as an opti

There’s no clearly defined biological reason for it, and it is intuitively an evolutionary disadvantage.Sleeping during the night was extremely important for human survival. We evolved to find food during the day. Any waking hours at night time instead of sleeping means a huge amount of extra energy expended to support being awake. Sleep pressure has a huge evolutionary advantage. It may be a disadvantage now.

Is it really such a mystery anymore?Routine maintenance is prudent for any system. Sleep is a maintenance mode.At night, the sun goes down, it gets cold, predators come out. You save a ton of energy and maybe your life by avoiding activity at that time. When its cold you burn extra calories just to stay warm.Haven't biologists got a lot of evidence by now?

Polyphasic sleep seems to be the natural sleep-cycle of humanity, as proven through natural circadian rhythms.Sleeping for 8+ hours at one time, on a regular basis, may just not be natural for a significant percentage of humanity.

Maybe check the references in this article?https://theconversation.com/did-we-used-to-have-two-sleeps-r...

The argument is made that evolution is based on a light-dark cycle, but is also based on predators who prefer to catch prey asleep. Survival favored those who could awaken and stay awake until a threat has passed or until sustenance was secure. Sleep is often a luxury, and not due to unhealthy life always. And often we are entranced by what we are doing, living our dreams. Sleep is personal and largely subjective, there is no universal truth on it as long as we all have different lives.

Did humans evolve to sleep more than 6 hours at a time?

Maybe, but maybe not. Evolution only has to be better suited to the current environment, but it doesn't necessarily need to result in perfect creatures.Creatures could have developed the day/night awake/resting cycle independent of sleep just because at night you want to conserve energy to stay warm, and it's difficult to hunt at night.Once creature developed day/night modality, taking advantage of that time to run repair processes would be an evolutionary advantag