REM (Rapid-Eye-Movement) sleep:

Appeared in: IGNOU PB Bsc Nsg.Entrance-2026

Explanation

The human sleep cycle, which includes both NREM and REM stages, repeats approximately every 90 minutes.
REM sleep occurs at the end of each cycle.
The duration of REM sleep periods increases as the night progresses, starting short (e.g., 5-10 minutes) and lengthening to 30 minutes or more in later cycles.

Option A: The recurrence interval is incorrect. The entire sleep cycle is about 90 minutes, not 30 minutes.
Option C: This describes the approximate total duration of REM sleep over an entire 8-hour night, not the length of a single REM episode.
Option D: The recurrence interval is incorrect. A 20-minute cycle is too short; the established ultradian sleep cycle is much longer.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Physiology of Sleep Cycles as background academic context rather than a clinical decision trigger.
Understanding sleep cycles is crucial for nurses when assessing patients with sleep disorders like insomnia, sleep apnea, or narcolepsy.
Many medications, especially CNS depressants (like benzodiazepines) and stimulants, can interfere with the normal sleep architecture, particularly by suppressing REM sleep. This can lead to daytime fatigue and cognitive issues.
Patient education on sleep hygiene often involves explaining the importance of consistent sleep schedules to support the body's natural circadian rhythm and sleep cycles.

How to Approach the Question

First, identify the core concept of the question, which is the timing and duration of REM sleep.
Recall the basic structure of the human sleep cycle. Remember that sleep is not a single state but a series of cycles.
Focus on the key numbers associated with the sleep cycle: the total length of one full cycle (NREM + REM). The most commonly cited average is 90 minutes.
Consider how REM sleep behaves within that cycle. It occurs at the end of the cycle and its duration is not fixed; it gets longer throughout the night.
Evaluate each option against these facts. Eliminate options with incorrect cycle times (e.g., 20 or 30 minutes) and incorrect durations for a single episode (e.g., 100-120 minutes).

Concept Tested & Keywords

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E6 Medicine Harrison 22e Part 1 p. 251-253

E6 Nursing Fundamentals Taylor p. 212-214

Practise the full IGNOU PB Bsc Nsg.Entrance-2026

Attempt every question from this paper in a timed mock, then review the full solution for each one.