How does sleep architecture change from infancy to adulthood?

• A. Newborns cycle through sleep stages in 50-60 minutes, while adults have cycles of 90-120 minutes
• B. Infants have longer cycles than adults
• C. Sleep architecture is identical across ages
• D. Adults cycle 50-60 minutes, infants 90-120 minutes

Answer: (A)

Sleep architecture changes as the nervous system matures, so typical sleep cycles lengthen from infancy to adulthood. Newborns have relatively short sleep cycles, about 50–60 minutes, as their sleep rapidly moves through lighter sleep, deeper non-REM, and REM stages. As development progresses, the cycles lengthen to roughly 90–120 minutes in adults. Along with longer cycles, the proportion of REM sleep decreases and sleep becomes more consolidated at night, with longer blocks of non-REM sleep between awakenings. This explains why infants often show multiple naps and frequent awakenings, while adults usually experience a longer, more uninterrupted nocturnal sleep. The other statements don’t fit because infant cycles are not longer than adult cycles, and sleep architecture clearly changes with age rather than staying identical.