Sleep and other good stuff

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

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

Sleep Stages

While awake, and in twilight, alpha waves

Stage 1– Lasts about 5

minutes

– May experience hallucinations

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

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

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

Rapid Eye Movement

Heart rate risesBreathing becomes

rapid & irregularEyes dart about even

though lids are shutMost vivid dreams

occur during this stage

Eight Hours a Day???

NOT TRUE!!!Babies spend 2/3 of

their time sleepingAdults spend less than

1/3 sleeping If left to sleep, most

will sleep 9 hours

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

Sleep Deprivation

2nd 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

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