Sleep apnea

Sleep apnea is a sleep-related breathing disorder where a person’s breathing repeatedly stops and starts during sleep. These pauses can last from a few seconds to several minutes and often happen many times throughout the night. When breathing stops, the person may make choking or snorting sounds before starting to breathe again. Common signs of sleep apnea include feeling very sleepy during the day, loud snoring, and not feeling rested even after a full night’s sleep.

There are two main types of sleep apnea: obstructive sleep apnea, where the airway gets blocked, and central sleep apnea, where the brain does not send the right signals to breathe. Obstructive sleep apnea is more common and happens when the airway becomes narrowed or blocked during sleep. Central sleep apnea occurs when the brain temporarily stops telling the body to breathe. Both types can affect the body’s oxygen levels and may lead to serious health problems over time.

Sleep apnea is linked to many health issues, including a higher risk of car accidents, high blood pressure, heart disease, stroke, and diabetes. Treating sleep apnea often involves lifestyle changes like losing weight, avoiding alcohol, and quitting smoking, as well as using special breathing devices. Even though treatments exist, many people who could benefit from them do not use them regularly. Sleep apnea affects a large number of people worldwide, especially older adults and those who are overweight.

Signs and symptoms

Sleep apnea can cause loud snoring and pauses in breathing during sleep. People with this condition often feel very tired during the day and might even fall asleep while driving. Some people do not realize they have sleep apnea because their symptoms can vary widely.

If not treated, sleep apnea can lead to serious health problems like diabetes, high blood pressure, and heart disease. It can also affect mood and energy levels, making a person feel irritable or less focused.

Risk factors

Sleep apnea can happen to anyone, no matter their age, gender, or background. But some things can make it more likely. For example, having a larger neck, being overweight, or having big tonsils can increase the chance of sleep apnea.

Other factors that might raise the risk include being older, having certain health conditions, or living with habits like smoking or drinking alcohol. Some health issues, like heart problems or past strokes, can also be linked to a different type of sleep apnea.

Mechanism

Obstructive sleep apnea

Sleep apnea happens when the airway in the throat gets blocked during sleep. This can be due to the shape of the head and neck, or because certain muscles don’t work well while sleeping. When breathing stops, carbon dioxide builds up in the blood. Special sensors in the blood notice this and wake the person up, which opens the airway again so they can breathe. After this, oxygen levels go back to normal and the person falls asleep once more. This process can happen many times during the night, and it stops the person from getting deep, restful sleep.

Central sleep apnea

Another type of sleep apnea happens when the brain does not send the right signals to breathe. This can be caused by problems like heart failure or other serious health issues. When the brain’s signals to breathe are weak, breathing can become irregular or stop for short periods while sleeping.

Complications

Sleep apnea is a serious condition that can affect the whole body. If not treated, it can increase the chance of heart problems, such as high blood pressure, heart failure, irregular heartbeats, and strokes. People with sleep apnea may feel very tired during the day, which can make it dangerous to drive or operate machines.

Sleep apnea is also linked to a higher risk of severe illness from diseases like COVID-19. There is a connection between sleep apnea and memory loss diseases, because poor sleep can damage the brain over time. Treating sleep apnea with special breathing machines can help improve some of these problems.

Diagnosis

Classification

Sleep apnea used to be divided into strict groups, but now doctors see it as a range of problems. True central sleep apnea, where the brain doesn't tell the body to breathe, is very rare. Most sleep apnea involves the airway getting blocked during sleep.

Obstructive sleep apnea

Main article: Obstructive sleep apnea

Doctors diagnose obstructive sleep apnea when someone has trouble breathing during sleep because their airway gets blocked. They look for signs like pauses in breathing or very shallow breaths. To decide how serious it is, they count how often these pauses happen each hour.

Criteria

Doctors look for several signs to diagnose sleep apnea. These include feeling very sleepy during the day, having trouble staying asleep, feeling tired even after sleeping, or having other health problems. They also look for breathing problems during sleep, like stopping breathing or gasping. Tests can show if these problems happen often enough to be sleep apnea.

Polysomnography

The best test for sleep apnea is done overnight in a special sleep lab. Doctors watch many things, like brain waves, breathing, and oxygen levels, to see exactly what is happening while someone sleeps.

Central sleep apnea

Main article: Central sleep apnea

Central sleep apnea is when the brain doesn't send the right signals to breathe. This can happen for different reasons, such as heart problems or certain medicines. Special tests help doctors tell the difference between central sleep apnea and other types.

Mixed apnea

Some people have a mix of obstructive and central sleep apnea. This can show up when treatment for obstructive sleep apnea causes new breathing problems during sleep.

Management

The treatment for a type of sleep apnea called obstructive sleep apnea is different from another type called central sleep apnea. Treatment often begins with changes in behavior, and some people might try a special machine called a continuous positive airway pressure (CPAP) device. Doctors often advise avoiding alcohol, sleeping pills, and other medicines that can relax throat muscles, because these can make breathing stop during sleep.

Sleeping on your side instead of your back can help if your sleep apnea gets worse in that position. For moderate to severe sleep apnea, a CPAP machine is commonly used. This machine sends air through a mask to keep the airway open during sleep. While it works well, some people find it uncomfortable or notice side effects like dry mouth or nose irritation.

Being overweight can contribute to sleep apnea, so losing weight may help. For children, special dental treatments can widen the nasal passages and improve breathing. For adults, there are other dental options and surgeries that can also help open the airway. Doctors often consider these treatments for people who cannot use a CPAP machine or dental devices. There are also newer treatments like electrical stimulation of the airway and special mouthpieces that can help keep the airway open during sleep.

Prognosis

If sleep apnea is not treated, it can be very dangerous because the body does not get enough oxygen. This can harm the liver, especially causing fatty liver disease.

Sleep apnea can also affect the brain. Studies using special pictures of the brain show that people with sleep apnea may have smaller parts of the brain that help with memory. Scientists think that not getting enough oxygen during sleep might hurt these brain areas.

Sleep apnea can cause many health problems. Low oxygen levels in the blood can lead to seizures, even in people who don’t usually have them. For people with heart problems, low oxygen can cause chest pain, irregular heartbeats, or heart attacks. Over time, repeated episodes of sleep apnea can change the blood’s chemistry and cause other health issues.

Epidemiology

In 1993, a study called the Wisconsin Sleep Cohort Study found that about one in every 15 Americans had at least moderate sleep apnea. It also found that among middle-aged people, about 9% of women and 24% of men had it, but many did not know or get treatment.

Untreated sleep apnea can also cost more money. In the U.S., untreated sleep apnea patients cost about $1,336 more each year in health care than people without sleep apnea. This adds up to about $3.4 billion extra each year. It is still not clear if treating sleep apnea saves money on medical costs.

Frequency and population

Sleep disorders such as sleep apnea are a big health concern in the United States. About twenty-two million Americans may have sleep apnea, and many cases, especially moderate or severe ones, are not diagnosed.

Sleep apnea can affect people of any age, but it is more common in men older than 40 who carry extra weight.

History

Long ago, an old German story talked about someone who forgot to breathe while sleeping. Doctors have known about problems with breathing during sleep for a long time, but they didn’t fully understand why it happened.

A famous doctor named William Osler once used a term called "Pickwickian syndrome" after a character from a book by Charles Dickens. This description matches what we now know as obstructive sleep apnea.

Treatment

In 1981, a doctor in Sydney, Australia, created a machine called CPAP to help people breathe better while sleeping. At first, these machines were big and loud, but they got smaller and quieter over time. Because this treatment worked well, many special clinics were set up to help people with sleep problems, especially those who have trouble breathing at night.