Sleep apnea is a condition marked by abnormal breathing during sleep. People with sleep apnea have multiple extended pauses in breath when they sleep. These temporary breathing lapses cause lower-quality sleep and affect the body’s supply of oxygen, leading to potentially serious health consequences.
Sleep apnea is one of the most common sleep disorders in the United States. It can affect children and adults and people of both sexes, although it is more common in men.
Because of sleep apnea’s prevalence and potential health impact, it is important for people to be aware of what sleep apnea is and to know its types, symptoms, causes, and treatments.
What Are the Types of Sleep Apnea?
There are three types1 of sleep apnea:
- Obstructive Sleep Apnea (OSA): OSA occurs when the airway at the back of the throat becomes physically blocked. That obstruction causes temporary lapses in breath.
- Central Sleep Apnea (CSA): CSA happens because there is a problem with the brain’s system for controlling muscles involved in respiration, leading to slower and shallower breathing.
- Mixed Sleep Apnea: When a person has both OSA and CSA at the same time, it is referred to as mixed sleep apnea or complex sleep apnea.
Because the underlying causes are distinct, there are important differences in the symptoms, causes, and treatments of OSA and CSA.
How Common Is Sleep Apnea?
Obstructive sleep apnea is estimated to affect between 2-9% of adults2 in the United States, but many cases are believed to go undiagnosed3, which fits with studies that have found considerably higher rates of OSA. Precise prevalence is hard to determine because studies have used different criteria for diagnosing the condition. A consistent finding, though, is that OSA affects men more than women4. It can occur in people of any age but is more common in older adults.
Central sleep apnea has been found to affect around .9% of adults5 over the age of 40. It is found much more frequently in men than in women.
As this data demonstrates, OSA is much more common than CSA. For this reason, when people talk about “sleep apnea,” they are generally referring to OSA.
What Are the Symptoms of Sleep Apnea?
All three types of sleep apnea share certain common symptoms:
- Disrupted breathing in which a person’s respiration can become labored or even stop for up to a minute at a time
- Excessive daytime sleepiness
- Morning headaches
- Limited attention span or difficulty thinking clearly
Many of these symptoms arise because of poor sleep and decreased oxygen levels that occur as a result of interrupted breathing.
Some additional symptoms are connected to obstructive sleep apnea:
- Snoring, including snoring that is especially loud and involves gasping, choking, or snorting that may cause a person to briefly wake up
- Morning sore throat or dry mouth
- Frequent need to wake up to urinate6 (nocturia)
Chronic snoring is the most common symptom of OSA, but that doesn’t mean that everyone who snores has sleep apnea. Snoring is not a frequent symptom in people with CSA.
In general, a person with sleep apnea is not aware of their breathing problems at night. For that reason, they often only find out about the issue from a bed partner, family member, or roommate. Excessive daytime sleepiness is the most likely symptom to be noticed by people with sleep apnea that live alone.
What Are the Causes of Sleep Apnea?
Obstructive sleep apnea occurs when a person’s airway becomes blocked during sleep. Multiple factors have been found to increase the risk of blockage and OSA:
- Anatomical characteristics. The size and positioning of a person’s neck, jaw, tongue, tonsils, and other tissue near the back of the throat can directly affect airflow.
- Obesity. Being overweight is a leading cause of OSA and may be an underlying risk factor in up to 60% of cases. Obesity contributes to anatomical narrowing of the airway, and research has found that a 10% increase in weight can equate to a six-fold increase7 in OSA risk.
- Use of sedatives, including alcohol. Sedative medications and drugs can cause tissue in the throat to relax, making it easier for the airway to become obstructed.
- Family history. People who have one or more close relatives with OSA are more likely to develop OSA themselves.
- Cigarette smoking. People who smoke, especially heavy smokers, have been found to have OSA at a higher rate8 than people who don’t smoke.
- Sleeping on your back. This sleeping position makes it easier for tissue to collapse9 around the airway and cause blockages.
- Nasal congestion. People whose ability to breathe through the nose is reduced because of congestion are more likely to experience OSA.
- Hormone abnormalities. Hormone conditions like hypothyroidism10(underactive thyroid) and acromegaly11 (excess growth hormone) may increase the risk of OSA by causing swelling of tissue near the airway and/or contributing to a person’s risk of obesity.