An Overview of Diurnal Sleep and Disorders

From the Latin diurnus, meaning “of the day” or “daily,” diurnal refers to being active during, occurring in or pertaining to the daytime or repeating once every 24 hours.

Woman in eye mask asleep in bed
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The opposite of nocturnal, humans are a diurnal species because we are active during the day and sleep at night (unless we happen to work the night shift). Many flowers have a diurnal pattern, opening their blooms every morning.

If you have trouble sleeping during the night and instead sleep during the day, or your job forces you to keep nighttime hours, you may have or be at risk for a sleep disorder. Here are a few circadian rhythm disorders that can affect your daytime activity level and lead to diurnal sleep.

Shift Work Sleep Disorder

Shift work sleep disorder (SWSD) affects people who work at night or who work a frequently rotating schedule, and is most common in people who work between 10 p.m. and 6 a.m. These schedules go against the body's natural circadian rhythm, forcing workers to sleep during the day, instead of following the natural diurnal pattern. These people often have trouble adjusting to different sleep and week schedules, which interferes with sleep. If sleep interruption as a result of your work schedule is constant or very frequent and results in difficulty sleeping or feeling excessively tired, you likely have SWSD. If you aren't able to change your shift, talk to your healthcare provider for tips to find relief, which could include sleep medication in extreme cases.

Delayed Sleep Phase Syndrome

Most common in teenagers, delayed sleep phase syndrome is characterized by staying up very late into the night. It's not an issue to stay up until 2 a.m. if you're able to stay in bed until 10 or 11 a.m., but this becomes a problem if you have obligations, such as school or work, that require you to be up early. If you're unable to fall asleep earlier in order to avoid daytime sleepiness, you should talk to your healthcare provider. He or she may suggest therapy, lightbox therapy or possibly the use of supplements such as melatonin.


Another circadian rhythm disorder, narcolepsy works against the body's preferred diurnal pattern. It is a nervous system disorder that occurs when the body fails to regulate sleep and wakefulness, resulting in excessive daytime sleepiness and uncontrollable episodes of falling asleep during the day, even with enough sleep. These sudden episodes of falling asleep can happen at any time and during any activity, which can be very dangerous. Be sure to seek treatment, as certain medications can help.

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  • Cleveland Clinic. (2013, December 11). Narcolepsy Symptoms & Treatment | Cleveland Clinic.

  • Cleveland Clinic. (2013, May 15). Delayed Sleep Phase Syndrome: DSPS Symptoms, Causes, and Treatment.

  • Cleveland Clinic. (2013, October 22). Shift Work Sleep Disorder.

By Brandon Peters, MD
Brandon Peters, MD, is a board-certified neurologist and sleep medicine specialist.