Why do we need sleep?

Sleep keeps a child's brain and body working well: the brain clears waste, sorts new memories, and steadies feelings, while the body repairs tissue and supports growth. It is not an off switch. It is nightly maintenance that helps tomorrow feel possible.

One lovely detail is that a sleeping brain has its own rinse cycle. Fluid moves around brain cells more freely at night, carrying away leftovers from a busy day of thinking, noticing, trying, and learning. That quiet work is part of why rest can make a hard thing feel easier.