Stage Proportion Balance
topic
Healthy sleep architecture maintains specific proportions of each stage across the night: approximately 5–10% Stage 1, 45–55% Stage 2, 15–25% Stage 3 (slow-wave), and 20–25% REM — proportions that are disrupted by alcohol (suppressing REM), aging (reducing Stage 3), anxiety (extending Stage 1), sleep apnea (fragmenting all stages), and insufficient sleep opportunity (truncating REM-rich later cycles).
Role
Stage proportion imbalance is the hidden mechanism through which the majority of sleep quality problems operate — producing nights of adequate total duration but inadequate restorative composition. The person who sleeps 7.5 hours after two glasses of wine has the duration but not the architecture: their REM is suppressed by acetaldehyde metabolism in the second half of the night, producing emotional dysregulation, reduced creative problem-solving, and impaired memory integration the following day — outcomes they attribute to the wine's hangover rather than to the specific REM suppression it caused.