Children's Hospital Colorado

Circadian Rhythm

What are circadian rhythm sleep disorders?

A circadian rhythm sleep disorder describes when a child or teenager's internal body clock causes them to sleep at a time that is not normal for the rest of the family. The circadian rhythm refers to the natural, biological patterns humans and other animals experience in a day.

Teenagers are often described as "night owls" or are late to bed and late to rise. The usual night owl has no problems with daytime function; but occasionally, teenagers can develop a true problem, where they are severely sleepy in the daytime, unable to wake for school, lack the ability to go to bed early, or experience school failure or truancy. This is known as delayed sleep phase disorder, which is one kind of circadian rhythm sleep disorder. Delayed sleep phase is caused by genes that may be passed down from parents, which explains why "night owls" tend to run in families.

What causes circadian rhythm sleep disorders such as delayed sleep phase disorder?

The human body has a natural sleep rhythm which has a cycle of about 24 hours, called the circadian rhythm. The circadian rhythm affects sleep, body temperature, hormone functions and attention or school performance. These daily patterns are influenced by light during the day and darkness at night.

For example, changes in daylight are the main reason for the change in the circadian rhythm when a person travels to a new time zone, known as "jet lag." People get jet lag when their circadian rhythm does not agree with the normal wake and sleep times of the new environment. Delayed sleep phase disorder is another example of a Circadian Rhythm Sleep Disorder.

Who gets circadian rhythm sleep disorders?

The most common cause of daytime sleepiness is not getting enough sleep at night. But, some children with a delayed sleep gene will begin to experience delayed sleep phase problems as they become teenagers. Adolescence or puberty causes the gene to be expressed or "turn on." If allowed, affected teens would go to bed very late or in the wee hours of the morning, sleep soundly for more than eight hours, and wake up refreshed in the early afternoon.

One consequence can be difficulty falling asleep at a "normal" time or waking up in the morning to get to school on time. When an adolescent has nighttime insomnia, difficulty waking up in the morning or daytime sleepiness, a circadian rhythm sleep disorder such as delayed sleep phase disorder should be considered as a potential cause.

Helpful resources

  • The National Sleep Foundation offers a lot of information about sleep disorders, including this article about circadian rhythms.
  • American Academy of Sleep Medicine has more information about sleep research and how sleep disorders are treated.
  • Healthy Children provides parents with health information on a variety of health issues and is from the American Academy of Pediatrics.
  • Medline Plus provides easy-to-understand information based on the latest medical research with links to pictures, related topics, and other trusted sources.

What are the signs and symptoms of circadian rhythm sleep disorders?

  • Difficulty waking up in the morning or trouble getting to school on time
  • Insomnia, or difficulty falling or staying sleep
  • Daytime symptoms such as sleepiness, moodiness or irritability
  • Cognitive impairment, including failing classes or decreased school performance
  • Chronic absenteeism due to sleeping late
  • Early morning awakening can happen, but is less likely

What tests are used to diagnose circadian rhythm sleep disorders?

While there is no test to diagnose circadian rhythm sleep disorders or delayed sleep phase disorder, a thorough medical history, physical examination and review of sleep history can point to the diagnosis. Other helpful tools include keeping a sleep log or diary for several weeks that documents bedtime, wakeup time, how long it takes to fall asleep, if you feel rested, etc. These often show that teenagers "sleep in" or try to "catch up" on the weekends when their circadian rhythm does not interfere with school.

Another way to demonstrate a child or teen's natural sleeping pattern is to have him or her wear an actigraphy watch. The device looks like a wristwatch, but records the patient's movement, how much sleep occurs, how long it takes to fall asleep, how much time is spent awake throughout the night and the amount of light in the room. Results of an actigraph study can show a delayed sleep phase disorder and to help guide treatment.

If you are suspicious that your child or teen may have delayed sleep phase disorder, think about how he or she behaves during the day: What times is he most hungry?  When is she most alert?  How often is he late for school? An individual with delayed sleep phase disorder will not have an appetite in the morning but will be hungry at night. An affected teen will be tired in the morning and become more alert during the evening.

How do providers at Children's Hospital Colorado make a diagnosis?

For adolescents who have symptoms of a sleep disorder, a complete sleep evaluation is should be done to detect a possible circadian rhythm sleep disorder. Our providers may use sleep logs or actigraphy to help make the diagnosis.

How are circadian rhythm sleep disorders treated?

Treatment of circadian rhythm disorders starts by finding out a child's natural sleep patterns, then using sleep hygiene techniques or bright light therapy to help reset those patterns to be closer to desired wake and sleep times.

Sleep logs should be kept for at least two weeks to establish a child's natural sleep patterns. Sleep logs show providers the child's natural wake-up time and approximately how many hours of sleep the child needs. Ideally, these logs are collected during a vacation when kids and teens can sleep according to their own internal clocks. Otherwise, providers estimate natural wake-up time by looking at weekend sleep patterns.

In a clinic visit with the patient and parents, the desired wake-up time is decided. Since light is the body's biological "time keeper" the most reasonable approach to correct a child's circadian rhythm is with light therapy. Light therapy can range from exposure to natural sunlight to using a prescription light-box. Light therapy treatment plans are developed to shift patients' sleep times and wake times to match the family's goals. This plan is individualized for each patient, based on the patient's current sleep cycle and family situation.

Once the desired wake-up time is reached, it is important to maintain constant bedtime and wake up times. Even on weekends, teens should wake up within two hours of their weekday schedule, meaning no sleeping in on weekends. Naps should be avoided. Patients and parents need to be motivated for therapy to be successful. Sometimes, it helps to see a sleep psychologist.

Before starting medicine, over the counter remedies or bright light therapy, patients and parents should consult a provider at the Children's Hospital Colorado Sleep Center because certain conditions, such as bipolar disorder, may be worsened if not properly treated. Using bright light therapy inappropriately can make a delayed sleep phase disorder worse.

It is important not to miss other causes of daytime sleepiness or sleep disruptions, such as snoring and obstructive sleep apnea, movement disorders, narcolepsy and many others.

Patients should also follow these recommendations to improve their sleep hygiene:

  • Remain active and expose yourself to bright light during the day.
  • In children who are school age or older, napping during the day should be avoided because naps "steal" from nighttime sleep.
  • Regular exercise in the late afternoon or early evening can promote sleep, but avoid strenuous activity just prior to bed.
  • Quiet activities prior to sleep allow one to relax. This includes reading (with the light behind you, not shining directly into your face) and listening to soft music or relaxation tapes.
  • Avoid bright lights in the evening, especially 1 to 2 hours before bed. This includes television, computers, video games and cell phones.
  • Keep the bedroom environment comfortable, quiet and dark with a cool temperature and comfortable bed.
  • Beds are only for sleeping and not for other daily activities, like TV or homework.
  • Only stay in bed for as long as you are sleeping.
  • Turn the clock away from you.
  • Ignore intrusive ideas and thoughts. Write them down to give yourself or your child permission to forget them until the next day.
  • Caffeine stays active in the body for about 10 hours, so avoid caffeine after lunchtime (or altogether).
  • Everyone should be aware that nicotine and alcohol make sleep restless.

Why choose Children's Hospital Colorado for your child's circadian rhythm disorder?

The Sleep Clinic at Children's Colorado is made up of a team of providers that includes sleep physicians who specialize in pediatric pulmonology and pediatric ENT, a sleep-specialized psychologist, two sleep-specialized nurse practitioners and a sleep-specialized respiratory therapist.

We see children who have been referred from all over the Rocky Mountain region for evaluation of any and all sleep concerns. We will develop an individualized plan of diagnosing and treating your child's sleep issues with you. Our providers are actively involved in pediatric sleep research and train doctors to become pediatric sleep medicine specialists.

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