Obstructive sleep apnea is normally at its worst when the patient is:

Obstructive sleep apnea is normally at its worst when the patient is:

• A. In stage 2 on their side
• B. In REM on their back
• C. In stage 3 on their side
• D. In stage 2 on their side

Answer: (B)

Airway stability in obstructive sleep apnea is strongly affected by both sleep stage and body position. During REM sleep, most skeletal muscles—including the pharyngeal dilators that keep the throat open—lose tone due to physiological atonia. This makes the upper airway more collapsible. Lying on the back adds another factor: gravity pulls soft tissues of the throat toward the posterior pharyngeal wall, further narrowing or blocking the airway. Put together, being in REM sleep while supine creates the greatest tendency for the airway to collapse, leading to the most obstructive events. In contrast, sleeping on the side helps pull the tongue and soft tissues away from the back of the throat, and non-REM stages (like stage 2 or stage 3) maintain relatively more muscle tone, so obstructions are generally less severe.

Airway stability in obstructive sleep apnea is strongly affected by both sleep stage and body position. During REM sleep, most skeletal muscles—including the pharyngeal dilators that keep the throat open—lose tone due to physiological atonia. This makes the upper airway more collapsible. Lying on the back adds another factor: gravity pulls soft tissues of the throat toward the posterior pharyngeal wall, further narrowing or blocking the airway.

Put together, being in REM sleep while supine creates the greatest tendency for the airway to collapse, leading to the most obstructive events. In contrast, sleeping on the side helps pull the tongue and soft tissues away from the back of the throat, and non-REM stages (like stage 2 or stage 3) maintain relatively more muscle tone, so obstructions are generally less severe.