Why are humans who sleep flat on their backs in mortal danger?

Do you often wake up late at night? Do you sleep enough but are still sleepy during the day? Is your work life going well but you are depressed? These problems may be caused by sleep problems, but they may not necessarily be in the brain, they may be in the breathing, the so-called sleep apnea syndrome, also known as sleep apnea, a disease that kills people unknowingly.

According to statistics, about 1 billion people worldwide suffer from varying degrees of mild or severe sleep apnea syndrome, and about 3,000 people die of suffocation every day when they fall asleep.

Many people have the hope that they will end their lives by passing away in their sleep, but sleep apnea syndrome is not that harmless; it does not choose to arrive in one's later years, and too many people wither away before they have experienced the five flavors of life.

There are too many cases of people dying from sleep apnea syndrome, from middle-aged people in their 40s and 50s to young adults in their 20s and 30s, to children as young as a few years old.

In 2017, a 39-year-old man in Hong Kong, China, died from sleep apnea

Sleep apnea syndrome is a highly prevalent respiratory disorder, with 9% of men and 4% of women in the 30- to 60-year-old group suffering from moderate sleep apnea syndrome, according to the 1993 Wisconsin Sleep Study.

The prevalence of sleep apnea syndrome in the middle-aged population is 4.6%, a number that does not seem scary, but translates to the order of millions.

OSA prevalence in some regions of China

What's even scarier is that we often don't realize that we have sleep apnea syndrome, and awareness of the disease is not high, and many people don't realize that they can sleep through the night every day.

So, what causes sleep apnea syndrome?

This question is certainly complex, but we can also expand it to break it down properly. First of all, sleep apnea syndrome also includes obstructive, central, and a mixture of both, with obstructive being the most common.

Obstructive sleep apnea is a phenomenon in which the airway is blocked due to various factors, leading to interruption of airflow from the nose to the mouth, mainly due to the structure of our upper airway.

The pharyngeal structure of humans and other mammals is the same. To meet multiple functions such as vocalization, swallowing, and breathing at the same time, the movable epiglottis cartilage acts as a shunt, allowing food to enter the esophagus and air to enter the trachea.

Also because of this special functional requirement, the pharynx is composed of muscles and soft tissues and lacks bony support structures, making it prone to collapse.

For quadrupeds, normal standing and walking do not lead to changes in the structure of the pharynx, even when lying down and sleeping, the head is at most tilted to the sides.

Humans are special, especially in the supine sleeping position, under the action of gravity, the soft palate and the uvula will move toward the posterior wall of the airway, making the airway narrow or even completely blocked.

This condition does not occur when we are lying down but awake, but once we fall asleep, especially in deep REM sleep when the muscles are completely relaxed, similar to snoring.

Snoring is inseparable from obstructive sleep apnea, and the principle of both is similar, except that snoring is a mild narrowing of the airway, causing the uvula to vibrate and make snoring sounds, which is usually just a nuisance.

If the narrowing of the airway is more serious or even completely blocked, the body continues to maintain the action of breathing, but can not inhale air, the negative pressure instead makes the airway more blocked, and at this time our body can not get oxygen from the outside world, the blood oxygen level is reduced, and the heart is overloaded with work.

Sagittal anatomy of a normal person (left) and OSA (right)

This is similar to blocking the mouth of a vacuum cleaner with a plastic bag and getting into an impasse. If the blockage is not turned off and cleared, the motor of the vacuum cleaner will be overloaded and damaged as well.

Of course, the human body is not that stupid, and after sleep apnea occurs, we tend to wake up from deep sleep, and the airway obstruction is removed after muscle tension, which is the most common manifestation of obstructive sleep apnea syndrome.

First, the sound of grunting starts from small to large and then stops abruptly after resounding through the whole house, and a rough gasping sound comes after a few seconds or even tens of seconds of breath-holding, which may be accompanied by actions such as rolling over and convulsions, and so on, week after week.

Schematic diagram of the typical pathogenesis of sleep apnea during the occurrence of sleep apnea

Clinically, the apnea and hypoventilation index (AHI) will be recorded with professional sleep breathing monitoring instruments, and this index will be used as a criterion to determine the severity of sleep apnea syndrome.

In most countries, an AHI greater than or equal to 5 breaths/hour is considered to have mild sleep apnea syndrome, moderate 15-30 breaths/hour, and severe more than 30 breaths/hour.

Severe patients can have hundreds of apneas or hypoventilation in one night's sleep. The direct consequence is a drop in blood oxygen saturation, which of course can cause death by asphyxiation in the most severe cases, and in mild cases, the heart may be overloaded and lead to related cardiovascular disease attacks, which is still quite dangerous in general.

Even the mildest symptoms may cause a decrease in sleep quality, which simply means that you have slept for 8 hours, but you are still depressed and drowsy every day, which may also lead to serious consequences, such as a car accident in which you cannot focus on driving, and may even lead to depression and other mental problems.

Sleep apnea syndrome, like snoring, is very difficult to detect by itself, and not only that it is also very misleading. Under normal circumstances, if there is enough sleep still sleepy, will suspect the poor quality of sleep and then seek the help of sleeping pills.

However, for poor sleep quality caused by sleep apnea syndrome, it is more dangerous to take sleeping pills or sedatives, which may aggravate the symptoms of apnea and fall into a deadly cycle.

If you are reading this article and have similar mental depression and dozing, you may want to ask your family or housemates, whether they have a sudden suspension of snoring, it is best to go to the hospital and use professional sleep breathing monitoring equipment to monitor.

After so many "why" and "how", it's time to "how".

First of all, from the principle, a general approach is to try not to lie on your back, but choose to lie on your side or side head to minimize the impact of gravity on the pharynx.

According to the study, whether it is mild, moderate, or severe sleep apnea syndrome patients, the use of a side sleeping position can significantly reduce AHI, and can significantly reduce the number of breathing disorder events.

AHI values of OSA patients with different degrees of obstruction in 3 sleeping positions

Secondly, sleep apnea syndrome is also influenced by several factors, including snoring (it is possible to develop the disease without snoring, but snorers are more likely to develop the disease), age, obesity, gender, smoking, alcohol consumption, family history, and abnormal nasopharyngeal and oral structures.

Obesity is one of the most mentioned factors, and it is also a direction that can be changed through efforts, and weight loss is usually a very effective treatment, as is quitting smoking and drinking.

If the condition cannot be improved by these means, surgical treatment can also be sought, and artificial widening of the airway can also be treated for sleep apnea syndrome, of course, there are many types of surgery, and the specific circumstances need to be discussed, here will not expand.

The last and more popular treatment method recently is the use of a continuous positive pressure ventilation system, commonly known as a ventilator, the principle is to open the obstructed airway through the air pressure of the ventilator so that breathing remains open.

The effect of the ventilator is immediate, but there are some criticisms, positive pressure ventilation not only works when you breathe in, but also when you breathe out, which affects the comfort of normal breathing, and some patients respond that it also affects sleep.

In short, for sleep apnea syndrome, we should neither take it seriously nor overly panic, and calmly look at the timely medical treatment, the problem can always be solved. Pay more attention to yourself and your family and friends around you, and promptly reminding and informing them of the risks is the greatest kindness to them.

It is not easy to be born as a human being, even the most relaxed and comfortable sleep should also be a lot of trouble, difficult to fall asleep, shallow sleep is already very torturous, and sleep apnea syndrome brings the risk of death.

This suffocation and helplessness experienced by people are very touching, can only blame the human race is moving too fast, our lives every day to modern progress, but health is regressing, so it is no wonder that some sleep researchers began to take lessons from animals.

Perhaps one day, standing in front of the zoo window, we no longer squint and tease the animals, but quietly appreciate their sweet and peaceful sleep.