The Rhythms of Sleep Flashcards
Sleep alternates between what 2 periods?
- rapid-eye-movement (REM)
- non-rem (NREM)
The cycle between alternating REM and NREM sleep occurs how often?
-every 90 minutes or so
NREM periods are divided into how many stages?
-4
What happens in Stage 1?
- brain waves become small and irregular
- state of light sleep
What happens in Stage 2?
- brain emits occasional short bursts of rapid, high peaking waves (sleep spindles)
- minor noises do not disturb
What happens in Stage 3?
- in addition to sleep spindles, brain emits delta waves (very slow, very high peaks)
- breathing and pulse slows
- muscles are relaxed
What happens in Stage 4?
- delta waves take over
- deep sleep
- sleep stage for sleepwalking
How do the stages of sleep progress?
- sequence of stages takes 30-45min, then it reverses
- instead of going back to stage 1, we enter REM
Describe: transition into REM sleep
- brain emits long bursts of rapid, somewhat irregular waves
- heart rate increases, blood pressure rises, twitches may occur
- skeletal muscles go limp
Why do some call REM sleep “paradoxical sleep”?
-the brain is entirely active, the body is not
As REM and non-REM sleep alternate through the night, what happens?
- stage 3 and 4 get shorter, and may disappear
- time between REM and non-REM is highly variable between the individual and themself
Why is sleep beneficial to us?
- repairs cells
- rids waste
- conserves or replenishes energy sources
- strengthens immune system
- recovers abilities
When do the effects of sleep deprivation become unbearable?
-around 4 or more days in a row
What are the effects of chronic sleep deprivation?
- increased levels of stress hormone Cortisol
- mental flexibility, creativity, and attention suffer
- delusions and hallucinations possible
Define: Sleep Apnea
- breathing periodically stops for a few moments in sleep, can happen unconsciously
- a cause of daytime sleepiness
