Sleep

As a biological anthropologist (in a previous life) I understand that evolution has no directional goal, it simply states that there is a natural selection for those gene variations that yield a better chance of survival and subsequent reproduction (in that particular environment). We can look at many mammalian and human features and rationalize them with this lens. For example, we are standing on two feet which may have an advantage to see predators in tall grasses, or that we have eyes in the front of our head giving us stereoscopic vision for swinging better in trees.

Those variations gave a survival advantage and were then able to live to spread their genes.

Sleep is a puzzling evolutionary trait, what advantage is there to spending 30% of our lives in an unconscious, paralyzed state which makes us vulnerable to predators, not reproducing, protecting our offspring or getting nutrients? One theory is that mammalian life started out in this sleeping state and over time evolved to live in a waking state, as sleep is the price we paid in order to be in this waking state. Thinking about sleep being our proto-state helps in understanding its function a bit better, at least from an evolutionary point of view. Regardless, sleep is incredibly important in resetting our brain and body’s health. It helps to regulate hormones, our immune system, physical recovery, learning, solidify the creation of new memories, clean out the toxin buildup that accumulates throughout the day in the brain neurons, and emotional regulation just to name a few. There is a lot we do not know about the effects of sleep on the body but we see evidence that lack of sleep can affect every tissue in the body.