Circadian Rhythm Disorders

If you have advanced sleep-wake phase disorder (ASWPD), you may find it very difficult to stay awake in the early evening and wake up too early in the morning. This can interfere with work, school, or social responsibilities.

This is one of the most common circadian rhythm disorders. If you have delayed sleep-wake phase disorder (DSWPD), you may fall asleep later than you would like and find it difficult to wake up on time in the morning. Delayed sleep-wake phase disorder often interferes with work, school, or social responsibilities. You may get too little sleep, which can lead to daytime tiredness or anxiety.

If you have irregular sleep-wake rhythm disorder (ISWRD), you may have several short periods of sleep and wakefulness. You may be unable to sleep during the night and take multiple naps during the day due to excessive sleepiness. You may not feel rested after sleep.

This is often a temporary disorder that may affect you if you travel across at least two time zones in a short period. Your sleep-wake rhythm is out of sync with the local time at your destination, so you may feel sleepy or alert at the wrong time of day or night. Jet lag disorder is often more severe when you travel east, compared with traveling west.

Some people experience social jet lag, in which activities on weekends or days off occur at much later times than on weekdays or workdays. This is not considered a disorder.

This type of circadian rhythm disorder occurs when a person’s sleep-wake rhythm is not in sync with the 24-hour day. When this happens, your sleep times may gradually become more delayed. For example, your sleep time may be delayed to the point that you are going to sleep at noon instead of night. This often happens when light exposure is very limited, and it is common in people who are completely blind. You may have periods of insomnia and daytime sleepiness, followed by periods with no symptoms, when your circadian rhythms happen to align with your environment.

Shift work disorder affects those who work during the night or on a rotating schedule. Because of your work schedule, you may not be able to get uninterrupted quality sleep when your body needs it. Shift work disorder can cause insomnia, fatigue, and sleepiness while working at night.

• Risk Factors will discuss medical conditions, lifestyle habits, and other factors that can increase your chance of developing a circadian rhythm disorder.
• Treatment will discuss healthy lifestyle changes and medicines that your doctor may recommend if you are diagnosed with a circadian rhythm disorder.

The rhythm and timing of your sleep-wake cycle can change with age because of changes in your brain. Teens may naturally have a later bedtime than adults, which raises their risk for delayed sleep-wake phase disorder. Older adults, on the other hand, usually sleep and wake up early. This raises their risk for advanced sleep-wake phase disorder. Older adults are also at higher risk for shift work disorder and jet lag disorder.

People who work during the night have a higher risk for shift work disorder. Jet lag disorder is more common in pilots, flight attendants, athletes, and people who travel often for business.

Your genes may play a role in whether you naturally wake up early in the morning or go to sleep later at night. This genetic preference of an early or late bedtime can raise your risk for advanced or delayed sleep-wake phase disorder if your rhythm is out of sync with your environment or social responsibilities.

Mutations in certain genes can also raise your risk for circadian rhythm disorders. These include the genes that control your body’s circadian clocks and certain genes that affect brain development or health.

Lifestyle habits can raise your risk for circadian rhythm disorders. These include:

• Alcohol use
• Chronic caffeine use
• Frequent air travel
• Illegal drug use
• Lack of exposure to natural light during the day
• Unhealthy sleep habits such as regularly staying up late and nighttime exposure to artificial light, including light from a TV screen, a smartphone, or a very bright alarm clock

Several medical conditions can increase your risk for circadian rhythm disorders, including:

• Autism spectrum disorders
• Certain genetic conditions, such as Smith-Magenis syndrome, Angelman syndrome, and Huntington’s disease
• Conditions that affect eyesight, such as blindness and macular degeneration. This raises the risk for non-24-hour sleep-wake rhythm disorder.
• Conditions that cause damage to the brain, such as traumatic brain injuries, strokes, and brain tumors
• Mental health conditions, such as bipolar disorder, major depression, obsessive-compulsive disorder, and schizophrenia. This raises the risk of delayed sleep-wake phase disorder.
• Neurodegenerative diseases, such as Alzheimer’s disease, dementia, and Parkinson’s disease. These conditions are more common in older adults and can increase your risk for irregular sleep-wake phase disorder.

How do neurodegenerative conditions lead to circadian rhythm disorders?

Men are more likely to have advanced sleep-wake phase disorder than women.

Women may be more likely to experience circadian rhythm disorders at certain stages of life.

• Hormonal changes that happen during pregnancy, after childbirth, and at menopause can cause problems with sleep.
• Discomfort during pregnancy may also prevent good-quality sleep.
• After childbirth, sleep interruptions and nighttime exposure to light while caring for a newborn can increase your risk for circadian rhythm disorders.

To help lower your risk of circadian rhythm disorders, your doctor may recommend that you make healthy lifestyle changes and avoid bright light and caffeine close to your bedtime. While caring for a newborn at night, keep the lights as dim as possible.

You may be able to prevent a circadian rhythm disorder caused by external factors such as your environment.

The following steps may help prevent shift work disorder:

• Take a short nap before your night shift to help prevent sleepiness at work.
• Adopt a sleep schedule on your days off that overlaps with your sleep time on work days.
• Avoid multiple schedule switches between day and night shifts, if possible.

The following steps may help prevent jet lag disorder:

• A few days before traveling across several time zones, begin adjusting your sleep-wake cycle to match the time at your destination. You may gradually change your sleep schedule and use bright light to help advance or delay your waking time.
• If you can, arrive at your destination a few days before an important event, to help you gradually adjust to the local time. Your body adjusts to the time at your destination at a rate of 1 to 1.5 time zones per day.
• Spend plenty of time outside at your destination. Outdoor light may shorten symptoms of jet lag.

• Diagnosis will discuss tests and procedures that your doctor may use to diagnose types of circadian rhythm disorders.
• Living With will discuss what your doctor may recommend to prevent your circadian rhythm disorders from recurring, getting worse, or causing complications.
• Research for Your Health will discuss how we are using current research and advancing research to prevent circadian rhythm disorders.
• Participate in NHLBI Clinical Trials will discuss our open and enrolling clinical studies that are investigating prevention strategies for circadian rhythm disorders.

Common symptoms of circadian rhythm disorders include:

• Consistent difficulty falling asleep, staying asleep, or both
• Excessive daytime sleepiness or sleepiness during shift work
• Fatigue and exhaustion
• Lethargy
• Decreased alertness and difficulty concentrating
• Impaired judgment and trouble controlling mood and emotions
• Aches and pains, including headaches
• Stomach problems, in people who have jet lag disorder

How do circadian rhythm disorders affect judgment?

Circadian rhythm disorders may increase your risk for the following health conditions:

• A weakened immune system, which can lead to infections and poor recovery from illnesses
• Cardiovascular diseases, such as atherosclerosis or stroke
• Cognitive and behavioral disorders, such as decreases in attention, vigilance, concentration, motor skills, and memory. These can lead to reduced productivity, workplace mistakes, or road accidents. In teens and young adults, circadian rhythm disorders can cause risky behavior and problems with concentrating at school, controlling emotions, and coping with stress.
• Digestive disorders, such as stomach ulcers, gastroesophageal reflux disease (GERD), and irritable bowel syndrome. Circadian rhythm disorders may influence the signaling from the brain to the gastrointestinal tract. They may also increase inflammation in the bowel, which can lead to digestive symptoms.
• Fertility problems. Circadian rhythm disorders may disrupt the hormone cycle that controls fertility and reproduction.
• Metabolism disorders, which can lead to diabetes, metabolic syndrome, and overweight and obesity
• Mood disorders, including irritability, anxiety, and depression
• Worsening of other sleep disorders, such as sleep apnea

Do you want to learn more about how circadian rhythm disorders cause problems with metabolism in shift workers?

• Diagnosis will discuss tests and procedures used to detect signs of circadian rhythm disorders and help rule out other conditions that may mimic circadian rhythm disorders.
• Treatment will discuss treatment-related complications or side effects.

Your doctor will want to learn about your signs and symptoms, risk factors, your personal health history, and your family health history to help diagnose a circadian rhythm disorder. To do this, your doctor may do the following:

• Ask when, how long, and how well you sleep.
• Ask when your symptoms began. Symptoms that have lasted for three months or more may indicate a circadian rhythm disorder.
• Ask about your personal and family history of health conditions.
• Perform a physical examination.

Your doctor may have you undergo or use some of the following tests and measurements:

• A sleep diary to help you keep track of when and how long you sleep
• Actigraphy, in which you wear a small motion sensor for three to 14 days to measure your sleep-wake cycles
• Sleep studies to measure how well you sleep and how your body responds to sleep problems.
• Other studies to look at your natural patterns of sleep and wakefulness. Your doctor may repeatedly measure your body temperature and the levels of melatonin and cortisol in your blood or saliva. The way these factors rise and fall over time can help determine the type of circadian rhythm disorder you may have.

Do you want to learn more about how melatonin, cortisol, and body temperature work in someone with a healthy sleep cycle?

To rule out other causes of your symptoms, your doctor may do the following:

• Ask about your use of caffeine, nicotine, alcohol, or illegal drugs, as well as your exposure to artificial light at night. These lifestyle habits may cause insomnia or tiredness.
• Ask you to keep a sleep diary or have a specific type of sleep study to rule out other problems with sleep, such as insomnia, sleep apnea, and narcolepsy
• Ask you whether you have chronic pain that may be preventing good-quality sleep
• Examine you for heart or lung conditions that may prevent good-quality sleep
• Examine you for large tonsils or small airways to help rule out sleep apnea
• For women, ask whether you are pregnant or undergoing menopause

• Return to Risk Factors to review family history, lifestyle, or other environmental factors that increase your risk of developing circadian rhythm disorders.
• Return to Signs, Symptoms, and Complications to review common signs and symptoms of circadian rhythm disorders.

To help reset your sleep-wake cycle, your doctor may recommend that you establish a daily routine with set activities that happen during the day and another set of activities that happen at night. This may help manage the symptoms of circadian rhythm disorders caused by internal or external factors. A daily routine is especially important if you have complete blindness or cannot tolerate changes to your light exposure. Your daily routine may include:

• Adopting a regular meal schedule, especially if you are a shift worker or sleep at irregular times of the day or night.
• Adopting a regular bedtime routine. Sleep in a cool, quiet place and follow a relaxing bedtime routine that limits stress. These practices, along with regular sleep and waking times, can help you fall asleep faster and stay asleep longer.
• Avoiding daytime naps, especially in the afternoon. However, shift workers may benefit from a short nap before the start of their shift.
• Exercising regularly. Your doctor may recommend getting regular physical activity during the daytime and avoiding exercising close to bedtime, which may make it hard to fall asleep.
• Limiting your intake of caffeine, alcohol, nicotine, and some medicines, especially close to bed time
• Managing your exposure to light. Light is the strongest signal in the environment to help reset your sleep-wake cycle. You may need more sunlight during the day and less artificial light at night from TV screens and electronic devices. Artificial light can lower your melatonin levels, making it harder to fall asleep. Light-blocking glasses, screen filters, or smartphone apps can help dim the light from your electronic devices. Dim lighting for a period before bed may also help reduce the symptoms of a circadian rhythm disorder. For shift workers, wearing light-blocking glasses when you are outside during the day may help.

Your doctor may suggest that you try light therapy to treat some types of circadian rhythm disorders. With this approach, you plan time each day to sit in front of a light box, which produces bright light similar to sunlight. Light visors and light glasses may also be effective. Light therapy may help adjust how much melatonin your body makes to reset your sleep-wake cycle.

• To move your sleep and wake times earlier, use the light box when you wake up in the morning. This may also help reduce daytime sleepiness. This method may be used to help treat delayed sleep-wake phase disorder, irregular sleep-wake rhythm disorder, and jet lag disorder when you travel east.
• To move your sleep and wake times later, use the light box late in the afternoon or early in the evening. This method may be used to help treat advanced sleep-wake phase disorder, shift work disorder, and jet lag disorder when you travel west.

Side effects of light therapy may include agitation, eye strain, headaches, migraines, and nausea. Ask your doctor before using light therapy if you have an eye condition or use medicines that make you sensitive to light.

Your doctor may recommend melatonin medicines or supplements to help align your sleep-wake cycle with your environment. The choice depends on the type and severity of your circadian rhythm disorder. Options may include the following:

• Melatonin receptor agonists are medicines to treat non–24-hour sleep-wake rhythm disorder. Side effects can include dizziness and fatigue.
• Melatonin supplements are lab-made versions of the sleep hormone that your doctor may recommend to treat delayed sleep-wake phase disorder, irregular sleep-wake rhythm disorder, and non–24-hour sleep-wake rhythm disorder. These supplements are not regulated by the U.S. Food and Drug Administration. Thus, the dose and purity of these supplements can vary. Talk with your doctor about how to find safe, effective melatonin supplements, as well as any possible side effects or medicine interactions. Side effects of melatonin may include excess sleepiness, headaches, high blood pressure, low blood pressure, stomach upsets, and worsening symptoms of depression.

These medicines may not be recommended for people who have dementia or epilepsy, or who take the blood thinning medicine warfarin. Other people who need to consult a doctor before taking these medicines include women who are pregnant, trying to become pregnant, or breastfeeding.

Other medicines which may be used to treat the symptoms of circadian rhythm disorders include:

• Beta blockers to reduce the levels of melatonin in your body during the day
• Caffeine to help prevent daytime sleepiness. Your doctor may recommend that you avoid caffeine within eight hours of your desired bedtime.
• Sleep-promoting medicines, such as benzodiazepines and zolpidem, to help you fall asleep faster and stay asleep longer. These medicines may cause side effects and complications that may be more severe in older adults and people who have dementia. These complications can include confusion, headaches, poor medicine interactions, long-term dependence, muscle weakness, falls, and nausea.
• Wake-promoting medicines, such as modafinil and armodafinil, to help you stay alert and improve performance during shift work. The effects of these medicines may last only for a short time, and you may still experience some sleepiness.

• Research for Your Health will discuss how we are using current research and advancing research to treat people who have circadian rhythm disorders.
• Participate in NHLBI Clinical Trials will discuss our open and enrolling clinical studies that are investigating treatments for circadian rhythm disorders.
• Living With will discuss what your doctor may recommend including lifelong lifestyle changes and medical care to prevent your condition from recurring, getting worse, or causing complications.

It is important that you follow your doctor’s instructions to help avoid the symptoms and complications of circadian rhythm disorders. You may need to maintain a regular daily schedule, take your medicines as prescribed, and follow your doctor’s instructions for light therapy even when your condition improves. If your circadian rhythm disorder continues after appropriate lifestyle changes and treatments, you may need to adapt your daily routine to an early or late sleep phase.

Talk with your doctor about how often to schedule office visits and medical tests. Between visits, tell your doctor if you have any new symptoms, if your symptoms worsen, or if you have any complications because of your medicines.

Return to Treatment to review possible treatment options for your circadian rhythm disorder.

To monitor your condition and to help prevent complications, your doctor may recommend regular testing. These tests and measurements may include:

• Actigraphy testing to check periods of sleep and activity
• Body weight
• Melatonin levels
• Metabolism

Your doctor may also recommend that you keep a sleep diary to monitor improvements in your pattern of sleep and wakefulness and in your quality of sleep.

To avoid accidents caused by fatigue and daytime sleepiness, it is important to identify when you are too tired to drive, operate heavy machinery, or work. Consider using public transportation if you are too tired to drive.