Stages of sleep

NREM 1 sleep

light sleep,

-small, irregular beta waves that transition into alpha waves

NREM 2 sleep

sleep spindles appear, broken up by K complexes (large, slow waves); skeletal muscles relax

NREM 3

 delta waves, deep sleep 

-breathing and heart rate decrease 

-restorative sleep- helps the immune system, replenishment of hormones

REM

eyes move vigorously, associated w/ dreaming; brain waves: theta &beta

-Each sleep cycle is 90 min; as hours of sleep increase the time spent in NREM sleep decreases while REM sleep gets longer

-Sleep period goes from 1,2,3,4 and then retreats back to 1, and then enters REM 

-this sleep is for the brain 

If we do not get enough REM sleep then we can have REM Rebound 

Paradoxical Sleep

-the fact that REM is a very deep stage of sleep yet our brain waves resemble those observed when we are awake but the body is paralyzed from the neck down  

-brain is active and heart rate and blood pressure elevate

Night Terrors

-sleep disorder characterized by a frightened facial features and sounds

-can move and thrash around 

-little/no recall of event in the morning 

-NREM sleep disorder 

-more common in younger children

Sleep Apnea

person frequently stops breathing during the night and brain sends out an alert of lack of oxygen causing the sleeper to snort in air

-awakening himself to some degree but often without complete awareness

-correlated with obesity and muscle mass

Narcolepsy

inability to stay awake

-sudden, involuntary sleep where the person quickly enters REM sleep 

Insomnia

-lack of sleep: trouble falling asleep or staying asleep

-common occurrence when we are distressed

Somnambulism

-also known as sleepwalking 

-NREM sleep disorder where people will move around and perform activities while they are sleeping

REM Rebound

-if (in a REM deprivation studied) an individual is awakened at the onset of each REM period for some time, and then is allowed to sleep normally, the sleeper tends to have longer REM periods

-suggests that bodies need REM