TABLE 1.

Schematic synthesis of the most noticeable sleep changes across lifespan.

Sleep dynamics across lifespan	Perinatal	Childhood	Adulthood	Elderly
Sleep macrostructure	AS evolves into REM sleep and QS evolves in NREM sleep (0–4/6 months)	Decline of TST/WASO/SWS/REM sleep stage/number of sleep cycles	Decrease in sleep duration, SE, SWS and REM sleep stages	Higher sample entropy in NREM N2 and REM sleep stages
	Short ultradian cycle (30–70 min)	Increase of 1) mean cycle duration; 2) number of stage shift,; 3) N2 stage percentage	Increase in light sleep stages of NREM sleep; increase of SE	Decrease of SE/higher rate of sleeps disorders (e.g., OSA and insomnia)
	Mean sleep duration: 12.8 h	Mean sleep duration: 11.7 (toddler) 10.4 (3–5 years old)	Every 10 years reduction of total sleep time by 10 min and sleep efficiency by 1%–2%
Sleep microstructure	Alternating periods of short-duration, high-voltage activity separated by lower-voltage activity (TA); appearance of sleep spindles (3 months); High levels of CAP fluctuations (mainly subtypes A1)	Increase density and coherence of sleep spindles; persistence of high levels of CAP oscillations	Gradual increase of CAP rate (subtypes A2 and A3; decrease of subtypes A1)	Decline in K-complex and spindles amplitude and density; Steeper increase of CAP rate (subtypes A2 and A3; decrease of subtypes A1)

AS, active sleep; QS, quiet sleep; TST, total sleep time; WASO, wake after sleep onset; SWS, slow wave sleep; SE, sleep efficiency; OSA, obstructive sleep apnea; TA, trace alternant; CAP, Cyclic alternating pattern.