reathing-related sleep disorders are conditions in which the patient's sleep is interrupted by problems in his or her breathing. These pauses in respirations are termed apneas or hypopneas. Apnea is a Greek word that means “without breath.” Apneas are breathing pauses that last 10 seconds or longer. Hypopnea is a reduction in inspiratory airflow, leading to a drop in the oxygen level in the blood. It comes from the Greek words hypo, meaning “under” or “less than normal,” and pnea, meaning “breath.”