Obstructive Sleep Apnea (OSA) is characterized by what main issue during sleep?

Obstructive Sleep Apnea (OSA) is primarily characterized by repetitive upper airway obstruction during sleep. This condition leads to temporary interruptions in breathing, often resulting in decreased oxygen levels and fragmented sleep. The obstruction typically occurs when the tissues in the throat relax excessively during sleep, causing a blockage of the airway. These episodes can occur numerous times throughout the night, prompting the brain to partially wake the person in order to reopen the airway, which disrupts sleep cycles and can severely impact overall quality of sleep.

While excessive dreaming, chronic sleepwalking, and daytime sleepiness are associated with various sleep disorders, they are not the defining characteristic of OSA. Daytime sleepiness can occur as a consequence of the fragmented sleep caused by the repetitive airway obstructions, but it does not address the underlying mechanism of OSA itself. Understanding OSA's primary issue of upper airway obstruction is crucial for recognizing its health implications and potential treatments.