Your body runs on an internal clock that causes you to feel sleepier at night and more awake and alert during the day.
This natural sleep-wake cycle, which repeats every 24 hours, is known as the circadian rhythm. It relies on environmental cues like light and dark, meal timing, and physical activity.
Taking steps to get on a more regular sleep schedule may help improve symptoms.
A circadian rhythm sleep disorder can impact many facets of your life. Each disorder type has unique symptoms. Most people with circadian rhythm sleep disorders have one or more of these symptoms:
- difficulty going to sleep
- difficulty staying asleep
- not feeling refreshed after sleeping
- feeling less alert
- memory issues
There are six circadian rhythm sleep disorders. Each one is defined by specific patterns of sleep disruption that result in insomnia or excessive daytime sleepiness. These conditions can have a negative effect on mental and physical health as well as daily functioning.
Advanced sleep-wake phase disorder (ASWPD)
People with this condition go to sleep earlier than most people, typically between 6 p.m. and 9 p.m. They also wake up early, around 2 a.m. to 5 a.m. People with ASWPD are more likely to be older adults.
Delayed sleep-wake phase disorder (DSWPD)
This is the most common circadian rhythm sleep disorder. People with DSWPD typically go to sleep later than others, and either wake up later than most or have trouble waking up on time. This condition is more common in adolescents and young adults.
Non-24-hour sleep-wake rhythm disorder (N24)
People with N24 have sleep patterns that don’t line up with the 24-hour day. Their sleep times become later and later until they’re eventually sleeping during the day. Around 55 to 70 percent of blind people have N24.
Irregular sleep-wake rhythm disorder (ISWRD)
A person with this condition sleeps for short periods that aren’t timed by their circadian system. As a result, they’ll sleep for several short episodes spread across the 24-hour day, with periods of wakefulness in between.
Jet lag disorder
This condition affects people of all ages and can occur when you travel by air across at least two time zones. The body often has difficulty adjusting to the new time. The greater the difference between time zones, the more significant the symptoms are.
Jet lag disorder is usually temporary, and it affects some people more than others.
Shift work disorder
This condition occurs in people who work during the night or early morning hours. People with shift work disorder have difficulty getting enough sleep in the daytime to compensate for lost overnight sleep.
Conditions that influence sleep patterns may be external or internal, and include:
- light exposure
- drinking caffeine at night
- travel across multiple time zones
- non-traditional work hours
- late-night social activities
- levels of physical activity
- medical conditions
- appropriate timing and release of melatonin, a sleep hormone
Disruptions of one or more of these factors may lead to a circadian rhythm sleep disorder.
You’re more likely to experience a circadian rhythm sleep disorder if you have certain medical conditions, such as:
- brain injury
- genetic conditions, like Smith-Magenis syndrome and Huntington’s disease
- neurodegenerative diseases, like Alzheimer’s disease and dementia
Additional risk factors include:
- working night shifts
- traveling frequently
- drinking alcohol or caffeine regularly
- using devices like TVs and smartphones at night
- often going to sleep late
Taking certain medications can also stimulate the body and make sleep difficult. These include:
A sleep medicine specialist can diagnose a circadian rhythm sleep disorder. They’ll likely ask about your symptoms and your medical history and perform a physical exam. To be diagnosed with a circadian rhythm sleep disorder, you must:
- have a disrupted sleep-wake pattern caused by problems with your circadian system
- experience insomnia, excessive sleepiness, or both
- have lower functioning at work or school or see an effect on your overall health
They will also check that you meet the criteria specific to each disorder.
The specialist may recommend that you keep a sleep diary. This diary details when you went to sleep and woke up for 1 to 2 weeks. Another option is actigraphy, where you wear a small sensor to measure periods of being awake and asleep.
A sleep medicine specialist may also suggest a sleep study. This involves sleeping under observation. You may wear sensors to monitor your heart rate, breathing, brain waves, and other functions during the sleep study. This helps rule out other conditions that may affect your sleep, such as obstructive sleep apnea.
The specific circadian rhythm sleep disorder you have will help determine the treatment. The goal of treatment is to realign your circadian rhythm to your desired sleep-wake schedule.
Common methods involve medications, lifestyle changes, and light therapy. A combination of treatments to promote better sleep may help you find relief.
Melatonin, a hormone that regulates sleep-wake cycles, can help promote sleep. Your doctor may prescribe a medication called a melatonin receptor agonist, but you can also buy melatonin supplements over the counter.
Remember to check with your doctor when taking a new supplement.
- flurazepam (Dalmane)
- temazepam (Restoril)
- triazolam (Halcion)
Nonbenzodiazepine sedative-hypnotics are another class of Food and Drug Administration (FDA)-approved medications that treat insomnia. They don’t cause a significant rebound effect, or a return of symptoms, after stopping the medication compared with benzodiazepines.
Still, they may cause confusion, loss of balance, and falls. Medications include:
You may benefit from improving your sleep routine if you have a circadian rhythm sleep disorder. Changes may include:
- avoiding naps during the day
- following a set sleep schedule
- performing quiet activities, such as reading, before going to sleep
- making your bed more comfortable
- avoiding bright lights at night
- sleeping in a cool, quiet room
It’s best to avoid caffeine, nicotine, and strenuous physical activity before bed. It may also help to limit alcohol, which can disrupt sleep. Other beneficial lifestyle habits may include eating at regularly scheduled times and getting enough exercise.
You can also try light therapy at home, which can involve using a light-producing box or indoor lights to adjust your sleep cycle. Using the box in the morning may help you wake up earlier, while evening use may help you delay your sleep. A 2019 research review found that light therapy improved sleep in people with DSWPD.
Getting enough sleep is important for your health. If you have a circadian rhythm sleep disorder, it may place you at greater risk of:
- a weaker immune system
- cardiovascular diseases
- a traffic accident
- trouble concentrating at work or school
Making simple changes to your sleep routine and light exposure may help you adjust your sleep schedule.