Chapter 6d Flashcards
Sleep relation to age
sleep duration and the proportion of REM sleep generally decreases as age increases. However, these trends occur at different rates as the proportion of REM sleep stops significantly decreasing from childhood onwards.
Neonatal period and infancy
Neonatal period (1–15 days)
• During this period, sleep duration is the highest it will ever be in the lifespan. New-born babies sleep for approximately 16 hours.
• Approximately 50% of the sleep episode is REM sleep and approximately 50% is NREM sleep.
Infancy (3–24 months)
• Sleep duration decreases to approximately 13.5 hours.
• The proportion of REM and NREM sleep also changes to
approximately 35% REM sleep and approximately 65% NREM sleep.
Childhood and adolescence
Childhood (2–14 years)
• Sleep duration decreases again to approximately 11 hours.
• The proportion of NREM sleep increases slightly to around 80%
of the sleep episode, while REM sleep decreases to approximately
20% of the sleep episode.
• As the childhood period is a significant amount of time, there are
slight variations across this period. For example, sleep duration starts at around 12 hours when children are about two years old, and decreases to around 10 hours when children are about 14 years old. REM sleep also starts at around 25% of the sleep episode and decreases to around 18.5% of the sleep episode.
Adolescence (14–18 years)
• Sleep duration decreases again to approximately 9 hours.
• The proportion of REM and NREM sleep remains fairly constant
at 20% REM and 80% NREM sleep.
• Adolescents also experience a biological delayed sleep onset by
1–2 hours, meaning they are more likely to become sleepier later and wake up later.
Young adult middle adult and old age
Young adulthood (18–30 years)
• Sleep duration decreases again to approximately 7.75 hours.
• The proportion of REM and NREM sleep remains fairly constant at 20% REM and 80% NREM sleep.
Middle adulthood (30–75 years)
• Sleep duration remains at approximately 7–8 hours.
• The proportion of REM and NREM sleep remains fairly constant at 20% REM and 80% NREM sleep.
Old age (75+ years)
• Sleep duration continues to decrease to approximately 6 hours.
• The proportion of REM and NREM sleep remains fairly constant
at 20% REM and 80% NREM sleep.
• Older adults tend to experience advanced sleep phase syndrome,
which is a biological shift forward in their sleep-wake cycle, meaning they become sleepier earlier and wake up earlier.
Why sleep changes during age
An individual’s sleep requirements change because their physical and cognitive needs change over time. REM sleep has been suggested to be important for the brain and cognitive development and rest, whilst NREM sleep has been suggested to be important for physiological rest and development. The explanations for the differences in sleep across the lifespan are discussed in table 2.
Notable differences of sleep
Notable difference in sleep across lifespan:
Neonatal period and infancy
Time spent in REM sleep is significantly high because newborns and infants are experiencing rapid brain development.
Childhood Time spent in REM sleep starts to reduce as the pace of brain development steadies.
Adolescence In adolescence, sleep patterns can change due to various social factors that play a role in the decreased proportion of sleep during adolescence, such as having to wake up early for school and having social commitments during the nighttime. Adolescents are also more prone to delayed circadian phase disorders in which their biological ‘clocks’ are not in alignment with the demands of their environments.
Adulthood and old age In older adults, lower levels of sleep tend to be attributed to ill-health and an increase in the prevalence of sleep disorders, as well as the reduced amount of cognitive and physical growth within this age group.
Sleep requirement
sleep requirements, meaning the amount of sleep an individual requires, at their specific age, in order to healthily function. However, due to other factors (whether internal or external), individuals often do not meet these requirements. This explains why there are some discrepancies (across different sources) in the number of hours individuals sleep at specific stages of the lifespan, as it may either be based on what they require or what they typically average.
Age group sleep requirement
Age . Sleep required. Average sleep
Neonatal period (1–15 days)
14–17
16–18
Infancy (3–24 months)
12–15
13–5
Childhood (2–14 years)
10–14
11
Adolescence (14–18 years)
8–10
9
Young adulthood (18–30 years)
7–9
7.75
Middle adulthood (30–75 years)
7–9
7–8
Old age (75+ years)
7–8
6
