How much sleep you need changes as you age. Although the amount of sleep you get each day is important, other aspects of your sleep also contribute to your health and well-being. Good sleep quality is also essential.
https://www.cdc.gov/sleep/about_sleep/how_much_sleep.html
Sleep Evolved Before Brains. Hydras Are Living Proof
https://www.cdc.gov/sleep/about_sleep/how_much_sleep.html
Sleep Evolved Before Brains. Hydras Are Living Proof