We all know that insomnia is on the rise and sleep deprivation can have disastrous results (e.g., mistakes and accidents). This talk by Matthew Walker gives you all the surprising details, but even more interesting is a mention in Dr. Mercola's recent newsletter about sleep:
Quote: Healthy sleep consists of several stages, and you cycle through these stages four to five times during the nightly sleep cycle. As a result, you're progressively descending into deep sleep and ascending toward lighter states of sleep several times, and this cycling is tremendously important, both from a biological and psychological perspective.
During stages 1 and 2, your brain remains active as it begins the editing process where decisions are made about which memories to store and which to discard. During stages 3 and 4, you enter into a deeper, almost coma-like state, during which the actual physiological cleansing and detoxification processes in the brain take place.
Your brain cells actually shrink by about 60 percent during this deep sleep phase. This creates more space in-between the cells, giving your cerebrospinal fluid more space to flush out the debris. Lastly, in stage 5, you enter rapid eye movement (REM) sleep, where dreaming takes place. All of these stages are important, and it's important to cycle through them enough times each night — especially the deeper stages. When stages 3 and 4 are missing, your brain gets clogged with debris associated with Alzheimer's disease and, indeed, sleep deprivation is a risk factor for severe dementia.