2. Sleep Apnea
Sleep apnea is a condition in which breathing stops for more than 10 seconds during sleep. Sleep apnea is a major, though often unrecognized, cause of daytime sleepiness.
Healthline.com (OMS Preferred Provider)

3. Sleep Apnea Information Page: National Institute of Neurological Disorders and Stroke (NINDS)
Sleep apnea is a common sleep disorder characterized by brief interruptions of breathing during sleep.  These episodes usually last 10 seconds or more and occur repeatedly throughout the night.  People with sleep ...
www.ninds.nih.gov