A chronic medical condition where the affected person repeatedly stops breathing during sleep. These episodes last 10 seconds or more and cause oxygen levels in the blood to drop. It can be caused by obstruction of the upper airway, resulting in Obstructive Sleep Apnea, or by a failure of the brain to initiate a breath, called Central Sleep Apnea. It can cause and worsen other medical conditions, including hypertension, heart failure, and diabetes.