<unk>  (SWSD) is a circadian rhythm sleep disorder characterized by insomnia, excessive sleepiness, or both affecting people whose<unk>  hours overlap with the typical sleep period. Insomnia can be the difficulty to fall asleep or to wake up before the individual has slept enough. About 20% of the<unk> ing population participates in<unk> <unk> . SWSD commonly goes undiagnosed, so it's estimated that 10–40% of<unk> <unk> ers suffer from SWSD. The excessive sleepiness appears when the individual has to be productive, awake and alert. Both symptoms are predominant in SWSD. There are numerous<unk> <unk>  schedules, and they may be permanent, intermittent, or rotating; consequently, the manifestations of SWSD are quite variable. Most people with different schedules than the ordinary one (from 8 AM to 6 PM) might have these symptoms but the difference is that SWSD is continual, long-term, and starts to interfere with the individual's life.
Shift work sleep disorder
Circadian rhythm sleep disorder
Central sleep apnea
Sleep apnea
Sleep disorder
Sleep deprivation
Obstructive sleep apnea
Sleep-related breathing disorder