1. Sleep and other good stuff

2. Biological Rhythms  Annual cycles- migration, hibernation  28 day cycles- menstruation  24-25 hour cycles- body temp., hormone secretion  90 minute cycles- cycle through sleep stages

3. Circadian Rhythm  Regular body clock that operates on a 25 hour cycle  People’s clocks vary… night owls vs. early birds  Can be disturbed by many external factors

4. Sleep Stages  While awake, and in twilight, alpha waves  Stage 1 –Lasts about 5 minutes –May experience hallucinations

5. Sleep Stages cntd.  Stage 2 –Lasts about 20 minutes –Characterized by sleep spindles (rapid bursts of brain-wave activity) –Sleep talking can occur –People are clearly asleep at this point

6. Sleep Stages cntd.  Stages 3 & 4 –Beginning of slow wave sleep (Delta waves) –At this point, it’s very hard to wake people up –Lasts about 30 minutes –End of stage 4 marked by bed wetting or sleep walking (somnambulism) in children

7. Sleep Stages Information  Ascend from stage 4 up through stage 2  Spend about ½ the night in stage 2  Instead of going back to stage 1, REM occurs  Time spent in stage 4 decreases until no longer exists

8. Rapid Eye Movement  Heart rate rises  Breathing becomes rapid & irregular  Eyes dart about even though lids are shut  Most vivid dreams occur during this stage

9. Eight Hours a Day???  NOT TRUE!!!  Babies spend 2/3 of their time sleeping  Adults spend less than 1/3 sleeping  If left to sleep, most will sleep 9 hours

10. Sleep Debt  Brain keeps track of how many hours you sleep about every 2 weeks  Brain isn’t satisfied by 5 hours, 5 hours, 5 hours, 13 hours  It wants consistency

11. Sleep Deprivation  2 nd leading cause of fatal car accidents  Can also lower your immune system  Accidents increase immediately after daylight saving (spring ahead) –Canada – 7% higher on the Monday after –U.S. – 17% higher on the Monday after

12. Why do we need sleep?  Sleep protects us from the dangers of night  Restores body tissues, especially the brain  May play a role in growth process – during sleep, pituitary gland releases growth hormones