Hypopnea: Literally, underbreathing. Breathing that is shallower or slower than normal. Hypopnea is distinct from apnea in which there is no breathing. Hypopnea comes from the Greek roots hypo- (meaning low, under, beneath, down, below normal) and pnoe (meaning breathing). SLIDESHOW Sex-Drive Killers: The Causes of Low Libido See Slideshow From Healthy Resources Good and Bad Foods for PsoriasisBest Foods for Inflammation and PSADiet Tips to Help Boost Heart Health Featured Centers Good and Bad Foods for PsoriasisVideo: Getting Personal on Life With MS Health Solutions From Our Sponsors Shot-Free MS Treatment Your Child and COVID-19