Getting enough sleep is vital to your physical and emotional health. Important things to know:

• Most adults need seven to eight hours of sleep.
• One in three American adults report regularly sleeping less than seven hours a night, according to the Centers for Disease Control and Prevention.
• Two in three high school students report sleeping less than eight hours a night, according to 2017 CDC data.
• Too little sleep can lead to a variety of short- and long-term problems.
• At least 40 million Americans have a long-term sleep disorder, according to the National Institute of Neurological Disorders and Stroke.

What are sleep disorders?

Sleep disorders are conditions that disrupt your ability to get enough high-quality sleep. The International Classification of Sleep Disorders — the most widely used system — identifies six major categories, plus a category for additional types.

Why is sleep so important?

Scientists believe we need sleep to do things such as:

• Learn and preserve memories
• Clear toxins from brain cells
• Regulate hormones
• Repair damaged tissues
• Control emotions and behavior

Not getting enough sleep can put you at risk for short- and long-term problems, such as:

• Increased risk of obesity, diabetes and depression.
• Learning, emotional and behavior issues.
• Weakened immune system.
• Increased risk of work or car accidents. The National Highway Transportation Safety Administration blames drowsy driving for nearly 800 deaths in 2017.
• Relationship conflicts

Who gets sleep disorders?

Tens of millions of Americans have a sleep disorder, according to estimates. Precise numbers are difficult to pin down, though, because:

• Data is often based on surveys, not monitored sleep tests.
• Definitions of terms such as insomnia vary.
• Statistics are repeated without the original source, or they trace back to a source that’s 10 or more years old.
• Sleep disorders are intertwined with many other conditions.

Available information includes:

• The portion of Americans with sleep apnea surged from the 1980s to 2010, according to a study published in the American Journal of Epidemiology in 2013. Scientists linked the increase to the rise in obesity rates.
• The study estimated that among adults ages 30 to 70, about 13% of men (about one in eight) and about 6% of women (about one in 17) had moderate to severe obstructive sleep apnea.
• About one in six U.S. adults reported having trouble falling asleep four or more times in the previous week, according to the CDC’s 2012-14 National Health Survey.

Causes of sleep disorders

Sleep disorders can be caused by physical, emotional and mental health issues. They can also be linked to other conditions. Factors include:

• Weight: If you carry excess weight, fat deposits around your nose and throat may block your breathing. This can cause apnea, in which breathing repeatedly stops for a few or more seconds during sleep.
• Mental health: Trauma, depression, mental illnesses and stress can lead to insomnia and other sleep disorders.
• Shift work: Night shift workers often have trouble getting enough sleep to stay healthy. A growing body of research shows possible connections between night shift work and diseases such as cancer.
• Hormone changes in women: Hormone shifts in menstruation, pregnancy and menopause can affect sleep patterns. Hot flashes during menopause, for example, can disrupt sleep.
• Long distance travel: Frequent business and professional travelers across multiple time zones often struggle to sleep enough hours to maintain good health.
• Environmental conditions: Nighttime light and noise, particularly in cities, may disrupt your body’s circadian rhythm (body clock) and upset your sleep routine.
• Chronic medical conditions: People with health issues such as Alzheimer’s disease, Parkinson’s disease, chronic headaches, heart disease or cancer often develop sleep disorders.
• Secondhand sleep issues: Partners who snore, grind teeth or talk in their sleep, or children who awaken during the night, can disrupt the sleep of others.
• Medications: Antidepressants, antihistamines, asthma medications, and drugs and alcohol all may contribute to insomnia.

Symptoms of sleep disorders

If you have any of these signs or symptoms, see your doctor. Your doctor might want to refer you to a specialist or schedule you for a sleep study.

• Long periods of not breathing, which may indicate apnea
• Excessive daytime sleepiness
• Deep snoring, noise or restlessness while sleeping
• Irregular breathing or increased movement during sleep
• Difficulty falling asleep
• Headaches upon waking
• Consistent nightmares
• Physical reactions to dreams

Types of sleep disorders

The International Classification of Sleep Disorders defines six categories, plus a category for disorders that don’t fit a category. Among the categories are dozens of subtypes.

Some common sleep disorder categories and types are:

Insomnia: People with insomnia can’t go to sleep or stay asleep at night. Chronic insomnia may be a symptom of other problems, such as depression or anxiety, chronic stress or pain. Insomnia is considered “acute” if it’s short term, lasting a night to a few weeks. Insomnia is considered chronic if it occurs at least three nights a week for three months.

Obstructive sleep apnea: This occurs when the soft tissues in your throat block your upper airway, cutting off your oxygen supply for a few seconds. You wake up and breathe again. These hundreds of brief awakenings cause daytime sleepiness, the main symptom of the disorder.

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Central sleep apnea: This type is rare but important to understand because of the link to opioid use. It occurs when you repeatedly stop breathing during sleep because your brain does not prompt your body to breathe. In addition to opioids, it is sometimes associated with congestive heart failure or prior stroke.

Narcolepsy: People with this chronic genetic disorder may experience:

• Severe daytime sleepiness
• Dreamlike hallucinations while falling asleep or waking up
• Temporary muscle weakness

Diagnosis can be difficult, and treatment is often with medication. Scientists know that narcolepsy involves the body's central nervous system, but they have not identified its cause.

Restless legs syndrome: This neurological disorder triggers an irresistible urge to move your legs shortly after you get into bed, in the middle of the night or during the day. It is twice as common in women than men and becomes more common with age.

Periodic limb movement disorder: This is repetitive cramping or jerking of the legs during sleep. Most people with restless legs syndrome also have this disorder.

Teeth grinding: Also called bruxism, this condition is more common among heavy drinkers, smokers or people who are under stress. Some teeth grinders use a mouth guard at night to reduce wear on their teeth.

Snoring: This common breathing problem occurs when air flows past relaxed tissues in your throat, causing vibrations in the mouth and upper throat. It is sometimes linked to obstructive sleep apnea. Learn about OHSU treatment options for snoring. 

Circadian rhythm (body clock) disorders: Common disruptions of our circadian rhythms are jet lag and night shift work. Habits and techniques can help you lessen the effects of a disruptive schedule.

Parasomnias (abnormal movements): These disorders may be symptoms of other health or emotional issues. They include:

• Sleepwalking: This occurs when the parts of your brain that control walking and physical activities stay active while you sleep. It is common among both adults and children. It is rarely dangerous.
• Sleep terrors: Also called night terrors, this form of sleepwalking may cause people to scream, break into a sweat or get out of bed abruptly.

 Sleep talking: Also known as somniloquy, this common behavior in adults and children does not need treatment.

Learn how OHSU researcher Matthew Butler, Ph.D., seeks to understand how clocks in body tissues operate.

Learn more

• Sleep and Sleep Disorders, Centers for Disease Control and Prevention
• Sleep Science and Sleep Disorders, National Heart, Lung, and Blood Institute
• Sleep Disorders: In Depth, National Center for Complementary and Integrative Health 
• Sleep Disorders, American Sleep Association
• Brain Basics: Understanding Sleep, National Institute of Neurological Disorders and Stroke
• What are Sleep Deprivation and Deficiency? National Heart, Lung, and Blood Institute
• Essentials in Sleep,  American Academy of Sleep Medicine
• Insomnia, National Heart, Lung, and Blood Institute
• Narcolepsy, National Heart, Lung, and Blood Institute
• Sleep Apnea, National Heart, Lung, and Blood Institute
• Sleep Apnea, U.S. National Library of Medicine