Question

As the sleep cycle evolves through the night, people tend to: A. spend more time in REM sleep and less time in NREM sleep. B. spend more time in NREM sleep and less time in REM sleep. C. spend a more or less equal amount of time in REM sleep and NREM sleep. D. spend more time in stage 4 sleep and less time in REM sleep.

Short answer

Question: As the sleep cycle progresses through the night, people tend to: A) Spend more time in REM sleep and less time in NREM sleep B) Spend more time in NREM sleep and less time in REM sleep C) Spend equal amounts of time in REM and NREM sleep D) Experience only REM sleep throughout the night Answer: A) Spend more time in REM sleep and less time in NREM sleep

Step-by-step solution

Understand the terms

First, let's get an understanding of the two main types of sleep: REM (Rapid Eye Movement) sleep and NREM (Non-REM) sleep. REM sleep is characterized by rapid eye movements, increased brain activity, and vivid dreams. NREM sleep is divided into four stages, from light sleep (stage 1) to deep sleep (stage 4). During NREM sleep, brain activity, heart rate, and breathing slow down.

Sleep cycle progression

Throughout the night, humans go through multiple cycles of NREM and REM sleep, with each cycle lasting approximately 90-120 minutes. In every sleep cycle, we first go through NREM stages (from stage 1 to stage 4) before entering REM sleep. As the night goes on, the amount of time spent in each stage changes.

Changes in REM and NREM sleep

As the sleep cycle evolves through the night, the time spent in REM sleep increases and the time spent in NREM sleep (specifically in deep sleep stages) decreases. So, the answer should reflect this change.

Identify the correct answer

Comparing the given options to our understanding of sleep cycle changes, we can identify the correct answer: Option A) spend more time in REM sleep and less time in NREM sleep.