Obstructive Sleep Apnea (OSA) is a sleep disorder in which the airway becomes blocked during sleep, causing repeated pauses in breathing. This leads to loud snoring, gasping, poor sleep, morning tiredness, and daytime sleepiness. If untreated, OSA can affect the heart, brain, mood, and overall health, but it can be diagnosed with a sleep study and treated with lifestyle changes, CPAP therapy, or medical care.