What percentage of total sleep time (TST) does REM sleep account for in adults?

In adults, REM sleep typically accounts for about 20-25% of total sleep time (TST), although individual variations can occur. This percentage reflects the role that REM sleep plays in health and cognitive function, including memory consolidation and emotional processing. While REM sleep is a critical stage of the sleep cycle, it does not constitute the majority of total sleep duration.

Recognizing that it generally does not exceed 30% is crucial in understanding sleep architecture and its implications for various sleep disorders. The correct answer, indicating that REM sleep makes up less than 30% of total sleep time, is consistent with this well-documented range found in sleep studies. Understanding these percentages is important for assessing sleep quality and diagnosing potential sleep-related issues.