AQA PSYA3 - Biological Rhythms - Lifespan Changes in Sleep

Prenatal sleep

• Okai (1992) studied REM and NREM of unborn babies of 30 pregnant women.
  • By 32 weeks REM could be identified. 
  • This correlates with development of neural structures in the brain which are known to be responsible for sleep stages.

Newborns

• Spend an average of 16 hours sleeping per day.
• Shorter cycle than adults.
• Have 2 sleep stages; quiet sleep and active sleep. 
  • These are immature versions of SWS and REM.
• In first months sleep is equally divided between the two.

Infancy

• By 6 months a circadian rhythm is established.
• By 1 year infants sleep mainly at night.
• SWS lengthens and REM reduces.

Childhood

• 5 years: have adult EEG pattern, but sleep 12 hours per day. Sleep is 30% REM.
• Boys sleep more than girls.
• Need for sleep gradually decreases.

Adolescence

• Sleep increases to 10 hours per day.
• Circadian rhythm changes; feel more awake at night, find it difficult to wake up early (phase delay).

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