Sleep is a very active process, different than being awake, but it has four stages stages. One and two are light, and I can easily wake you up by calling your name. Stage three is deep. Restorative sleep is what we all want. It's where we make our growth hormone that keeps us young or testosterone that keeps us sexy. Our immune proteins that fight off infection and cancer in the world of neurology. Right now, stage three. Sleep is very exciting because it's where we clean up the proteins that are head. That can cause Alzheimer's disease. When we're old, then we have REM sleep, rapid eye movement, Sigmund Freud believed we did our emotional processing during our dreams, but we also know now that's where we'd make our memories. We consolidate memories. All four stages are important. And what should happen in the average adult sleep is cycles of these four stages. One, two, three REM brief awakening, one, two, three REM brief awakening, and each cycle tends to last about 90 minutes, maybe up to 120 minutes. We do this hopefully four or five, six times during the night with the brief awakenings in between sleep is active. It's busy and it's vital for good life.