You kinda do - it's one of the most common causes of sleepyness during the day. Obstruction of airways during sleep (apnea -> transient oxygen deprivation -> stress -> short interruptions of sleep and arousal). And it's common too: >40% has some kind of sleep apnea. 20% stress, 10% restless legs, and 10% because of obstructive sleep apnea (OSAS, obesity). I bet OSAS is a lot more common than that in the US.