Written and medically reviewed by Kwaku Osafo-Mensah, MDPulmonary Medicine | Sleep Medicine | Diplomate, American Board of Sleep Medicine (ABSM)Medically reviewed: August 2026 Sleep apnea does not always occur evenly throughout the night. For some people, obstructive breathing events become substantially more frequent—or more physiologically significant—during rapid eye movement (REM) sleep. A sleep-study report may … Continue reading REM-Related Sleep Apnea: What Does REM AHI Mean?