The types of circadian rhythm disorders are advanced or delayed sleep-wake phase disorder, irregular or non\u201324-hour sleep-wake rhythm disorder, and shift work or jet lag disorder. The type you may have is based on your pattern of sleep and wakefulness.
\nTo better understand circadian disorders, read our How Sleep Works Health Topic.
\nIf you have advanced sleep-wake phase disorder (ASWPD), you may find it very difficult to stay awake in the early evening and wake up too early in the morning. This can interfere with work, school, or social responsibilities.
\nThis is one of the most common circadian rhythm disorders. If you have delayed sleep-wake phase disorder (DSWPD), you may fall asleep later than you would like and find it difficult to wake up on time in the morning. Delayed sleep-wake phase disorder often interferes with work, school, or social responsibilities. You may get too little sleep, which can lead to daytime tiredness or anxiety.
\nIf you have irregular sleep-wake rhythm disorder (ISWRD), you may have several short periods of sleep and wakefulness. You may be unable to sleep during the night and take multiple naps during the day due to excessive sleepiness. You may not feel rested after sleep.
\nThis is often a temporary disorder that may affect you if you travel across at least two time zones in a short period. Your sleep-wake rhythm is out of sync with the local time at your destination, so you may feel sleepy or alert at the wrong time of day or night. Jet lag disorder is often more severe when you travel east, compared with traveling west.
\nSome people experience social jet lag, in which activities on weekends or days off occur at much later times than on weekdays or workdays. This is not considered a disorder.
\nThis type of circadian rhythm disorder occurs when a person\u2019s sleep-wake rhythm is not in sync with the 24-hour day. When this happens, your sleep times may gradually become more delayed. For example, your sleep time may be delayed to the point that you are going to sleep at noon instead of night. This often happens when light exposure is very limited, and it is common in people who are completely blind. You may have periods of insomnia and daytime sleepiness, followed by periods with no symptoms symptom (SIMP-tum):
A problem that a patient experiences that may indicate disease but cannot be seen and does not show up on medical tests or procedures; some examples include headache, fatigue, nausea, or pain. , when your circadian rhythms happen to align with your environment.
Shift work disorder affects those who work during the night or on a rotating schedule. Because of your work schedule, you may not be able to get uninterrupted quality sleep when your body needs it. Shift work disorder can cause insomnia, fatigue fatigue (fuh-TEEG):
A condition following a period of mental or physical activity that is marked by extreme tiredness or weariness and inability to function due to lack of energy. Fatigue may be acute or chronic. , and sleepiness while working at night.