"Non-24-hour sleep–wake disorder (non-24, N24SWD, or N24) is one of several chronic circadian rhythm sleep disorders (CRSDs). It is defined as a "chronic steady pattern comprising daily delays in sleep onset and wake times in some people living in a society. Symptoms result when the non-entrained (free-running) endogenous circadian rhythm drifts out of alignment with the light–dark cycle in nature.

Although this sleep disorder is more common in blind people, Non-24 may also be comorbid with bipolar disorder, depression, and traumatic brain injury. People with non-24 experience daily shifts in the circadian rhythm such as peak time of alertness, body temperature minimum, metabolism and hormone secretion. These shifts do not align with the natural light–dark cycle. Non-24-hour sleep–wake disorder causes a person's sleep–wake cycle to move around the clock every day, to a degree dependent on the length of the cycle. This is known as free-running sleep.

People with the disorder may have an especially hard time adjusting to changes in "regular" sleep–wake cycles, such as vacations, stress, evening activities, time changes like daylight saving time, travel to different time zones, illness, medications (especially stimulants or sedatives), changes in daylight hours in different seasons, and growth spurts, which are typically known to cause fatigue. They also show lower sleep propensity after total sleep deprivation than do normal sleepers.

Non-24 can begin at any age, not uncommonly in childhood. It is sometimes preceded by delayed sleep phase disorder.

👍🏼🌟🏆 appreciated
pls leave a 👍🏼 before🗨️comment💬
thanks 🧡 yall"