In normal sleep architecture, stage 2 sleep makes up what percent of total sleep time?

In normal sleep architecture, stage 2 sleep makes up what percent of total sleep time?

• A. 5-10%
• B. 25-30%
• C. 40-50%
• D. 50-60%

Answer: (B)

Stage 2 sleep is the most prevalent NREM sleep stage in adults and usually makes up about a quarter to a third of total sleep time. The commonly cited range is 25-30%. This stage is marked by distinctive EEG features like sleep spindles and K-complexes and represents the transitional phase between lighter sleep (Stage 1) and deeper sleep (Stage 3). Because it dominates the night, it accounts for the largest portion of NREM sleep across multiple sleep cycles, with REM periods becoming longer in later cycles. That’s why the 25-30% figure is the best fit for normal sleep architecture.

Stage 2 sleep is the most prevalent NREM sleep stage in adults and usually makes up about a quarter to a third of total sleep time. The commonly cited range is 25-30%. This stage is marked by distinctive EEG features like sleep spindles and K-complexes and represents the transitional phase between lighter sleep (Stage 1) and deeper sleep (Stage 3). Because it dominates the night, it accounts for the largest portion of NREM sleep across multiple sleep cycles, with REM periods becoming longer in later cycles. That’s why the 25-30% figure is the best fit for normal sleep architecture.