A good night’s sleep is crucial for a healthy and productive day, not to mention a good and healthy life. A simple way to understand why we sleep is to think of what our bodies do when we exercise or even just go for a long walk. After a time (shorter for some, longer for others), we get tired and have to rest our aching muscles. We may sit down, drink some water, or eat an apple. We feel rested and then resume our activities. We need to rest because we burn and use energy. The brain works the same way. When we think, read, or speak, we use energy. There are biochemical waste products that build up even in our brains, and the brain needs to rest through sleeping. This allows the brain to get rid of those biochemical wastes and recoup that energy. Our brain needs rest (in …