U4 AOS1 Dot Point 7 and 8 Flashcards
2 theories to explain the purpose of sleep
restorative theory
evolutionary theory
what is the restorative theory of sleep
we sleep in order to recover from depleting activities during the day which use up our physical resources
replenishes energy stores and allows damaged cells to repair
restorative theory REM vs NREM
REM restores and repairs the brain
NREM restores and repairs the body
evidence for the restorative theory (NREM)
tissue repair occurs in stage 3 and 4 NREM sleep
people who ran marathons spent more time in stage 3 and 4 sleep
a study on rats found that sleep deprivation caused tissue breakdown
evidence for the restorative theory (REM)
developing foetus spends more time in REM sleep when their brains are developing quickly
what is REM rebound
if a loss of REM sleep has occurred it will be caught up the next night
limitation of the restorative theory of sleep
more active people don’t sleep more than less active people
what is the evolutionary (circadian) theory of sleep
sleep is a means of survival
evidence for the evolutionary theory of sleep
when asleep organisms are not active and less likely to be seen by predators
humans sleep at night because we have bad night vision
limitations of the evolutionary theory of sleep
eventually we must sleep even if we are in danger
when we are asleep we are vulnerable to predators
trends of sleep across the lifespan
amount of sleep decreases
proportion of REM decreases a lot after 2 years then remains stable
proportion of NREM decreases
proportions of REM and NREM in infants
16 hours
50% REM
proportions of REM and NREM in 2 year olds
12-13 hours
20-25% REM
proportions of REM and NREM at the start of adolescence
9-11 hours
20-25% REM
proportions of REM and NREM in adolescence
9 hours
20-25% REM
