1. SLEEP!

2. Importance of Sleep 1.Sleep Protects: Sleeping in the darkness when predators loomed about kept our ancestors out of harm’s way. 2.Sleep Recuperates: Sleep helps restore and repair brain tissue. 3.Sleep Helps Remembering: Sleep restores and rebuilds our fading memories. 4.Sleep and Growth: During sleep, the pituitary gland releases growth hormone. Older people release less of this hormone and sleep less.

3. The Beginnings of Sleep (sometimes known as Stage 0) o you are actually still relatively awake (although sometimes drowsy) o brain produces small and fast beta waves o You may experience hypnagogic hallucinations (examples: feeling like you are falling or hearing someone call your name) o Another very common event during this period is known as a myoclonic jerk (aka “sleep start” – when you wake up startled) Stage 1 beginning of the sleep cycle relatively light stage of sleep brain produces high amplitude theta waves, which are very slow brain waves. lasts between 5-10 minutes

4. Stage 2  brain begins to produce bursts of rapid, rhythmic brain wave activity known as sleep spindles  lasts for approximately 20 minutes  body temperature starts to decrease and heart rate begins to slow Stage 3 deep, slow brain waves (delta waves) begin to emerge during transitional period between light sleep and a very deep sleep.

5. Stage 4 o sometimes referred to as delta sleep o deep sleep that lasts for approximately 30 minutes o bed-wetting and sleepwalking are most likely to occur at the end of stage 4 sleep. Stage 5 (REM Stage)  REM = rapid eye movement  REM sleep is characterized by:  eye movement  increased respiration rate  increased brain activity.  voluntary muscles become paralyzed.

6. The Sequence of Sleep Stages o Sleep begins in stage 1 and progresses into stages 2, 3 and 4. o After stage 4 sleep, stage 3 and then stage 2 sleep are repeated before entering REM sleep. o Once REM sleep is over, the body usually returns to stage 2 sleep. o Sleep cycles through these stages approximately four or five times throughout the night. o On average, we enter the REM stage approximately 90 minutes after falling asleep. o The first cycle of REM sleep might last only a short amount of time, but each REM cycle becomes longer. REM sleep can last up to an hour as sleep progresses.