NREM Stages Flashcards
NREM stage 2
Light sleep, decreased body movement, respiration, blood pressure and temperature and heart rate.
Mostly theta waves
Slower and more amplitude than stage 1
Sleep spindles ( frequency) and k complex (amplitude) occurs.
NREM stage 1
It is the earliest stage of sleep.
Gradual loss of awareness, relaxed muscles, irregular breathing.
Decrease in heart rate, respiration, body temperature and muscle tension.
Hypnic jerk
Decrease in alpha waves and increase in theta waves.
Lasts for about 5-10 minutes
How long does stage 2 last for?
20 minutes
NREM stage 3
Moderately deep sleep.
Further reduced heart rate, respiration, blood pressure, body temperature.
Very relaxed state - mostly delta waves.
Also called slow wave sleep
How long does NREM stage 3 sleep last for ?
Up to 30 minutes duration but it decreases as the night progresses.
What waves occur in NREM stage 3?
Theta and Delta (50% is delta)
What happens in NREM stage 4
Deepest stage of sleep. Extremely relaxed, little or no movement.
Physiologically similar to stage 3
May experience night terrors, sleep talking and sleep walking
How long does NREM stage 4 last for?
20 minutes but decreases as the night progresses
What happens in REM sleep
Eyeballs move rapidly under eyelids during sleep and is mostly associated with dreaming.
EEG shows mostly beta waves
Physiological reading are higher but person appears to be completely inert - paradoxical sleep.
Most dreaming occurs in this stage and dreams and more vivid and memorable then NREM sleep
What are the two main theories of the purpose of sleep?
Restorative theory
The survival or adaptive theory
What is the restorative theory and what does it suggest
The restorative theory suggests that sleep is vital for replenishing and revitalising the physiological processes that keep the mind and body functioning at our optimal level.
What is NREM sleep essential for?
NREM is essential for the restoration of our body, including repair of muscle and tissue damage and muscle fatigue.
