Sleep Disorders: Circadian Rhythm Disorder

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. Your normal circadian rhythm is set by the cycle of light and dark over 24 hours. It plays a key role in things like when you sleep and when you wake. Patterns of brain waves, hormone production, cell regrowth, and other activities are linked to this cycle.

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
  • Feeling alert during the day

Other symptoms may include:

  • Poor concentration
  • Impaired performance, including lower cognitive skills
  • Poor coordination
  • Headaches
  • Stomach problems

Circadian Rhythm Disorder Causes

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Things that can cause circadian rhythm disorders include:

  • Shift work
  • Pregnancy
  • Time zone changes
  • Medications
  • Changes in routine, such as staying up late or sleeping in
  • Health conditions including Alzheimer's or Parkinson's disease
  • Mental health disorders
  • Menopause

Circadian Rhythm Disorder Diagnosis

Talk to your doctor if:

  • You sleep poorly for more than 1 month and notice trouble concentrating, forgetfulness, less motivation, or severe daytime sleepiness
  • You have trouble falling asleep
  • You awaken in the morning feeling tired and unrefreshed

Your doctor will begin by asking about your symptoms, taking a medical history, and doing a physical exam.

They may also use:

  • Sleep logs. A sleep log identifies the sleep-wake cycles in your regular environment (when at home and not traveling or working odd hours). You’ll be asked to write down when and how well you sleep over a period of time.
  • Sleep studies. Usually done in a sleep lab, sleep studies monitor you during sleep, measuring levels of oxygen, number of times you stop breathing, and how much you snore.
  • Imaging studies, such as CT scan and MRI, can check for neurological diseases, sinus infections, or blocked airways.
  • Epworth Sleepiness Scale. This questionnaire rates responses to eight situations, on a scale of 0-3, of their associations with sleepiness.
  • Actigraphy. You’ll wear a motion sensor on your nondominant wrist for a week to measure sleep-wake cycles.

Circadian Rhythm Disorder Treatments

Your treatment will depend on your 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 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.

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Medications to treat circadian rhythm disorders include:


This natural hormone is made by a gland in the brain at night (when it’s dark out). Melatonin levels in the body are low during daylight hours and high during the night.

Melatonin supplements, available over-the-counter, may be useful in treating jet lag and sleep-onset insomnia in elderly people with melatonin deficiency. But they haven’t been approved by the FDA, so it isn’t clear how much melatonin is safe and effective.

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