>>12842567Humans evolved to sleep at night because there's not much to do during the night when you can't see, so powering down the body saves calories. It also has the advantage of cleaning and repairing the brain.
The brain is the crown of the body - consumes like 25% of our calories while for sedentary people the muscles only use like 8% of calories. The energy used by the liver, heart, kidneys, and lungs can basically be seen as supporting brain power and consciousness. For some reason our brain just runs better with some sleep downtime to do some repairs and cleaning and memory storage. There is also a shift of consciousness during sleep where big problems can be solved by the subconscious mind that our waking state won't be able to solve as effectively.
