Why do adults need less sleep than children?

You may have heard that the average amount of sleep for everyone is about 8 hours.  It turns out, that is the average amount of sleep for an adult. When people are younger, they need much more sleep! Did you know that infants can often need 16+ hours of sleep?  Preschoolers often need 12+ hours of sleep.  Teenagers still can need 9-10 hours of sleep. 

This may make you wonder: Why do adults need less sleep than children?

Adults generally use less energy during the day than children, and so they have less need to restore that energy overnight. Sleep is a time when the energy demands of the body are less, and that gives the body time to restore its energy stores. Why do adults generally use less energy than children? Well, adults are no longer growing taller.  All that growth uses a lot of energy!  Some research suggests that in children, the body specifically produces “growth hormones” during sleep; as the name suggests, those growth hormones help with growing bones and muscle. Another reason why adults generally use less energy than children is because on average, adults move around much less than children, and all that movement requires energy! This is one of the reasons why, if you exercise as an adult, you will sleep better. Exercise leads to the release of various chemicals that help the body know when to sleep and when to stay awake.

Children’s brains are also growing and changing super quickly, making new connections based on all the new things they are learning. Sleep helps with all that learning, as we’ve written about in earlier blog posts (You can read lots more about sleep and memory if you scroll through our earlier blog posts). Of course, brains continue to make new connections throughout life, even into later adulthood, so sleep is always important!