Shifts between deeper and lighter sleep
A) occur only during the last half of a night's sleep.
B) occur just once per night unless the sleeper is suddenly awakened.
C) occur throughout the night.
D) are the first sign of sleep deprivation.

Question

Quizplus · Accepted Answer

Shifts between deeper and lighter sleep occur throughout the night. During a typical night's sleep, a person cycles through different stages of sleep, including non-REM (NREM) sleep and REM sleep, with each cycle lasting about 90 minutes. These cycles repeat throughout the night, with the proportion of time spent in each stage changing. In general, the first half of the night is characterized by deeper NREM sleep, while the second half of the night has more REM sleep. Within each stage, there may also be further fluctuations between lighter and deeper sleep.

Shifts Between Deeper and Lighter Sleep