We all have an internal clock that regulates certain biological functions over a 24-hour period. That clock is referred to as your circadian rhythm. Patterns of hormone production, appetite, and cell regeneration are associated with a person’s circadian rhythm. Your circadian rhythm also plays a role in your sleep-wake cycle.
Most people have a circadian rhythm that involves being awake during the daytime and sleeping at night. Certain factors affect your circadian rhythm including melatonin production. Melatonin is a hormone in the body that helps regulate sleep. Melatonin production is affected by sunlight. When you’re exposed to light, melatonin levels are low. But when light decreases, such as in the evening, your body makes more melatonin, which in turn makes you sleepy.
Keep in mind; there are individual variations in a person’s internal clock. For example, you might feel you are naturally a morning person, or maybe you consider yourself a night owl.
Types of Circadian Rhythm Disorders
As with many body functions, your circadian rhythm can get out of whack for a variety of reasons. For example, the demands of a job, newborn baby or travel can disrupt your body clock. When your internal rhythm is off, it can affect your sleep. There are several circadian rhythm disorders including the following:
Jet Lag: Jet lag is probably one of the best known circadian rhythm disorders. Jet lag is caused by changing time zones, which can disrupt light cues and regular bedtimes. In most cases, jet lag is temporary and regular sleep patterns return.
Sleep Shift Disorder: Sleep shift disorder involves problems sleeping due to your work schedule. In most cases, it occurs due to working overnight or rotating shifts. What happens is when you work overnight, your body needs to stay awake, which goes against your natural circadian rhythm. The conflict between what your internal clock wants to do and what you are forcing yourself to do disrupts normal sleep.
Delayed Sleep Phase Syndrome: Delayed sleep phase syndrome involves the inability to fall asleep at what is considered conventional bedtimes. For example, people with delayed sleep phase syndrome may not fall asleep until 2 or 3 am. Since bedtimes are much later than typical, people with the syndrome usually wake up later in the morning. The problem for people with delayed sleep phase syndrome is their sleep pattern may not match their school or work start time, which leads to excessive daytime sleepiness. The cause of delayed sleep phase syndrome is not entirely understood, but it is more common in teens.
Advanced Sleep Phase Disorder: Advanced sleep phase disorder is the opposite of delayed sleep phase syndrome. It involves problems staying awake during conventional or socially acceptable times. For example, people with advanced sleep phase syndrome may fall asleep at 7-8 pm and wake up very early at 3-4 am. The cause of advanced sleep phase syndrome has not been identified, but it occurs more commonly in the elderly.
Non-24 Hour Sleep-Wake Disorder: People with this disorder have a sleep-wake cycle that is longer than 24 hours. Their sleep and rise times drift a little later each night. Sleep times continue to change and eventually may go all the way around the clock. The condition is most common in people who are blind. It may occur in blind people due to lack of light and dark patterns to regulate sleep.
Symptoms of Circadian Rhythm Disorders
Symptoms of circadian rhythm disorders may vary in severity. Some people only experience problems, such as jet lag when traveling. In other cases, the disorder may be chronic and affect daily living. Circadian rhythm disorders often cause decreased quality of sleep, which can lead to sleep deprivation.
Symptoms of Circadian Rhythm Disorders may include:
- Problems falling asleep
- Daytime sleepiness
- Difficulty concentrating
- Decreased cognitive performance
Treatment for Circadian Rhythm Disorders
Treatment for circadian rhythm disorders may vary based on the severity of symptoms and the specific disorder. In most cases, one of the treatment approaches listed below is recommended.
Lifestyle and Behavioral Changes: In some instances, certain behavior and lifestyle changes may be all that is needed to treat a circadian rhythm disorder. Behavioral changes may include avoiding naps, caffeine and nicotine a few hours before bed. Adjusting exposure to light may also help. For example, if you have delayed sleep phase disorder, avoiding light exposure in the evening including light from cell phones and computers may be useful. Maintaining consistent bedtimes even on the weekends can also be helpful.
Light Therapy: Light therapy may be recommended for certain types of circadian rhythm disorders. Light therapy involves sitting in front of a bright light box for a certain amount of time prescribed by a sleep specialist. The treatment readjusts your body clock and is intended to delay or advance bedtime. The timing of the light therapy is based on the disorder.
Medications: If other treatments are ineffective, medication may be an option to treat a circadian rhythm disorder. Different classifications of medications may be used, such as benzodiazepines or nonbenzodiazepines, which promote sleep. Melatonin, which helps regulate sleep, may also be beneficial. Certain medications may only be recommended short-term due to the possibility of developing dependency.
MaryAnn DePietro, CRT is a medical writer and licensed respiratory therapist with over a decade of clinical experience.
Cleveland Clinic. Circadian Rhythm Disorders. https://my.clevelandclinic.org/health/articles/circadian-rhythm-disorders Retrieved May 2017.
Natural Institute of Health. Circadian Rhythm Abnormalities. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3654533/ Retrieved May 2017.
Stanford Health Care. Types of Circadian Rhythm Disorders. https://stanfordhealthcare.org/medical-conditions/sleep/circadian-rhythm-disorders/types.html Retrieved May 2017.
Circadian Rhythm Disorders FAQ
Are there risk factors for developing a circadian rhythm disorder? Although anyone can develop a circadian rhythm disorder including children and teens, certain factors increase the risk. For instance, people who frequently travel across time zones and those who work the night shift are at an increased risk.
How are circadian rhythm disorders diagnosed? If you suspect you have a circadian rhythm disorder, you should consider seeing a sleep specialist. You may be asked to keep a sleep diary, and a sleep study may also be recommended.
Do I need treatment if I have a circadian rhythm disorder? Since circadian rhythm disorders lead to a lack of quality sleep, treatment is beneficial. Treatments can improve regular sleep patterns and help you get the restorative sleep your body needs.
Is there a way to prevent circadian rhythm disorders? Although it’s not always easy, maintaining a consistent sleep schedule is one of the best ways to prevent a circadian rhythm disorder.