What Are Circadian Rhythm Disorders?
Circadian rhythm disorders are problems with your circadian rhythm, the "internal body clock" that keeps your biological processes in step. This cycle lasts about 24 hours. The term circadian comes from Latin words that mean “around the day.” Patterns of brain waves, hormone production, cell regrowth, and other activities are linked to this cycle.
Your circadian rhythm plays a key role in things like when you sleep and when you wake. Your normal circadian clock is set by the cycle of light and dark over 24 hours.
People with circadian rhythm disorders may have problems:
- Falling asleep
- Staying asleep
- Waking up too early and not being able to go back to sleep
- Getting sleep but not feeling refreshed by it
Circadian Rhythm Disorder Causes
Things that can cause circadian rhythm disorders include:
- Shift work
- Time zone changes
- Changes in routine, such as staying up late or sleeping in
- Medical problems including Alzheimer's or Parkinson's disease
- Mental health problems
Common Circadian Rhythm Disorders
- Jet lag, or rapid time zone change syndrome: This involves symptoms like too much sleepiness and a lack of daytime alertness in people who travel across time zones. It gets worse with each time zone crossed, especially when traveling toward the east.
- Shift work sleep disorder: This sleep disorder affects people who frequently rotate shifts or work at night. A conflict between someone’s circadian rhythm and the time of their shift can mean they get up to 4 hours less sleep than the average person.
- Delayed sleep phase syndrome (DSPS): This is a disorder of sleep timing. People with DSPS tend to fall asleep very late at night and have a hard time waking up in time for work, school, or social activities. It’s especially common in teens and young adults.
- Advanced sleep phase syndrome (ASPS): This is a disorder in which a person goes to sleep earlier and wakes earlier than they wanted. For example, they might fall asleep between 6 and 9 p.m. and wake up between 1 and 5 a.m.
- Non-24-hour sleep-wake disorder: This disorder often affects people who are blind because the circadian clock is set by the light-dark cycle. With this condition, that cycle is disturbed. It can cause a serious lack of sleep time and quality at night and sleepiness during daylight hours.
- Irregular sleep-wake rhythm disorder: With this disorder, people’s circadian rhythms are jumbled. They may sleep in a series of naps over 24 hours.
Circadian Rhythm Disorder Diagnosis
Your doctor will ask you to write down when and how well you sleep over a period of time.
You might also need something called actigraphy: You’ll wear a small device on your wrist that will record your movement so your doctor can learn more about your sleep cycle.
Circadian Rhythm Disorder Treatments
Your treatment for circadian rhythm disorder will depend on your specific condition. The goal is to fit your sleep pattern into a schedule that matches up with your lifestyle. Treatments may include:
- Bright light therapy. You reset your rhythm by being around a bright light for a certain time each day.
- Sleep hygiene. You’ll learn how to improve your circadian rhythm with changes to your bedtime routine or sleep environment.
- Chronotherapy. You slowly adjust your bedtime until it reaches the time you want.
- Lifestyle changes. Things like scheduling naps, being careful about your exposure to light, and avoiding caffeine or nicotine for some time before bed can help.
- Medication. Melatonin, stimulants, or hypnotics can change your sleep-wake cycle.