Which sleep disorder is strongly associated with obesity and nocturnal hypoxemia?

• A. Obstructive sleep apnea is strongly associated with obesity and nocturnal hypoxemia.
• B. Central sleep apnea is strongly associated with obesity and nocturnal hypoxemia.
• C. REM sleep behavior disorder is strongly associated with obesity.
• D. Circadian rhythm sleep-wake disorder is strongly associated with obesity.

Answer: (A)

Obstructive sleep apnea is driven by airway collapse during sleep, and obesity greatly increases the risk of this collapse. Extra soft tissue around the pharynx and a larger neck circumference narrow the airway, making it prone to obstruction when breathing stops or becomes shallow at night. Each obstructive event causes a dip in blood oxygen levels—nocturnal hypoxemia—and often brief awakenings to restart breathing. This combination—airway obstruction plus periodic desaturation—is the hallmark link to obesity and nocturnal hypoxemia.

Central sleep apnea, by contrast, comes from a lack of respiratory effort due to brain control of breathing, not from airway anatomy, so the association with obesity and nocturnal hypoxemia isn’t as strong. REM sleep behavior disorder involves dream-enacting movements during REM and isn’t primarily about oxygen desaturation or obesity. Circadian rhythm sleep-wake disorders involve misalignment of the sleep–wake cycle rather than oxygenation during sleep.

So the sleep disorder that best fits both obesity and nocturnal hypoxemia is obstructive sleep apnea.