Bed sheet

src: www.vikingwaterford.com A bed sheet is a rectangular piece of cloth used as bedding, being placed immediately below or above bed occup...

Sleep apnea

src: ent.uci.edu Sleep apnea , also spelled sleep apnoea , is a sleep disorder characterized by pauses in breathing or periods of shallow br...

Biphasic and polyphasic sleep

src: i.ytimg.com Biphasic sleep (or diphasic , bimodal or bifurcated sleep ) is the practice of sleeping during two periods over 24 hours,...

Narcolepsy

src: www.empowher.com Narcolepsy is a long-term neurological disorder that involves a decreased ability to regulate sleep-wake cycles. Symp...