Normal Sleep, Snoring, and Sleep Apnea

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man suffering from sleep apnea is sound asleep
Not all snorers have apnea, although they typically do. Your sleeping partner may notice pauses in breathing if you have apnea.

Why do we sleep?

No one knows why we sleep. People used to believe that sleep was a time for resting our brains. Polysomnography was then developed. This technology allows scientists to make electrical recordings of brain activity during sleep. Scientists were shocked to find that brains do not remain inactive during sleep.

One theory suggested that sleep is necessary to combat body fatigue. Although our bodies seem to be able to recover from fatigue while we sleep, studies have shown that our brains, and not our muscles, require sleep to function properly.

How much sleep do we need?

There are many factors that influence how much sleep you need.

We used to believe that babies required 21 hours of sleep each night. But, we now know that infants’ sleep requirements vary greatly from one infant to the next. Sixteen-year-olds need about 10 to 11 hours of sleep per night, while an adult needs around 8 hours.

Occasionally, healthy and alert adults can get 4 hours of sleep but this is very rare. Habitually, the average amount of sleep is about 3 hours per night. It has never been proven that anyone needs no sleep.

What happens when people are repeatedly deprived of sleep? The body’s physiological systems are affected by sleep deprivation: hormones and immune system, blood pressure regulation as well as the digestive system and urine production.

Many of our physiological functions have a 24-hour rhythm. Our biological clock is synchronized by the rhythms of going to bed and getting up in the morning. If a person is having trouble sleeping or has an irregular sleep schedule (for example, shift work), it does not send signals to the biological clock to reset its own clock each day and maintain synchronized rhythms.

The body will show signs of a disturbance if the daily rhythms don’t match, such as when someone works the night shift. Shift workers are more likely to suffer from digestive problems, headaches, or other types of cancer.

People who are sleep-deprived experience drowsiness from time to time. This is because their biological clock attempts to get them to go to sleep. Their ability to concentrate and ability to think dullens. Teenagers and school-age children are particularly affected by sleep deprivation. Many of them are severely sleep-deprived.

People who are sleep-deprived may also experience irritability, disorientation, and dreamlike hallucinations. The body’s reactions become slower and more erratic. Sleep-deprived drivers are more likely to cause accidents in their cars. Studies show that driving tasks like driving can be impeded by a person who sleeps only 7 hours per night. For one to have a high level of reaction time, nine hours must sleep every night.

Partial sleep deprivation by itself is not fatal. It can lead to fatalities if it affects the ability of the driver or passenger to drive safely on the highway. An average of four people are killed each time a long-haul truck driver crashes and falls asleep behind the wheel. Driving drunk while asleep is the same as driving drunk.

Sleep quantity, sleep quality and sleep debt

Each person needs to get a certain amount of sleep each night in order to be at their best. We can build up debt if we don’t get enough sleep. This can lead to feeling drowsy throughout the day and a greater likelihood of falling asleep quickly.

However, the quality of our sleep is only one aspect. Quality of sleep is equally important. Is it in long, uninterrupted blocks or broken up into smaller pieces? Is there enough deep sleep?

Sleep apnea is a condition that causes sleep to be interrupted repeatedly during the night. This reduces sleep quality and quantity. It also breaks down the structure and continuity of sleep. Sleep apnea causes people to miss some important and normal stages of sleep.

Let’s take a closer look at what happens in your brain when you sleep.

The Stages of Normal Sleep

The sequence of stages the brain goes through in the night determines the quality of sleep.

Your brain and body begin to settle down after you go to bed. There are two types of sleep: REM (rapid-eye movement) and nonREM (or NREM). REM and NREM sleep alternate during the night.

NREM sleep is quiet sleep. Your brain activity and breathing are slow and steady, and your body is calm and relaxed. Although you may have dreams, they will likely be more thought-like than emotionally.

Active sleep is REM sleep. REM sleep causes active changes to your physiology. Your breathing may become irregular. For several seconds, you may find your breathing stops. Your body temperature increases and blood circulation to your brain increases.

Your large muscles, your leg and arm muscles become paralyzed. You can’t move them other than a few twitches of the fingertips and face. Your eye muscles are activated and your eyes move back and forth like they’re playing ping-pong.

This is what gave rise to the term REM (rapid eye movement) sleep. REM sleep is where most of your dreams occur. REM sleep is where you will experience the most vivid, intense, and emotional dreams.

NREM is the first stage of a typical night’s sleep. NREM sleep progresses through four stages during the first hour, from light to deep sleep. Then, around 70 to 90 minutes after the start of sleep, the deepest levels of sleep begin to light to allow for the first REM phase. The first REM period lasts approximately 10 minutes. This is when the sleep cycle shifts into stage 2 NREM sleep. After that, the cycle begins all over again.

This process takes approximately 90 minutes and continues throughout the night. The REM periods are shorter in the morning. REM periods get longer in the second half of a night. They can last up to 60 minutes. Short periods of stage 2 NREM are also common.

Age affects the amount of REM sleep that a person gets during a normal night. Newborn babies sleep in REM for approximately half of their time. REM sleep is now less than one-quarter of the total time we sleep.

We all need REM sleep. However, we don’t know why. It could be related to REM dreams, which are when we “process” our emotions from waking life.

Our bodies seem to have an automatic mechanism that tries our best to get the right amount of REM sleep. People who are deprived REM sleep but then allowed to go to sleep normally often experience REM rebound.

This is when they have REM-like sleep for a prolonged period of time. It’s as if the bodies are catching up on what they missed and a sense that they have been deprived. People who experience REM rebound often dream more vividly and often have scarier dreams than usual.

Normal breathing during sleep

Breathing Centers and Reflexes

Automatic reflexes control your breathing during sleep. These reflexes are controlled by nerve system sensors that continuously monitor your blood chemistry and send signals to your brain’s breathing centers. Your breathing muscles are then able to control how strong and fast you can breathe at any given time. The brain’s respiratory centers regulate this activity, which is one reason for sleep apnea.

Sensors and “Setpoints”

Your carotid bodies are a group of sensors that monitor your blood chemistry. They are located in your neck’s carotid veins. They detect oxygen levels in your blood and react to low oxygen levels. These sensors aren’t the most important for your breathing reflex, even though oxygen is vital for life, especially for brain cells.

The medulla, a primitive and deep part of your brain, has a more powerful set of sensors. These sensors detect an increase in carbon dioxide levels in your cerebrospinal liquid (the fluid that bathes you brain and spinal cord).

Your body produces carbon dioxide as a waste gas when it uses up oxygen. Your cerebrospinal fluid has a high level of carbon dioxide. This is a sign that your body requires to breathe. You inhale carbon dioxide when you breathe and then exhale it immediately to get fresh air.

The “setpoint” is the concentration of carbon dioxide at which the sensors are activated. Although oxygen sensors work in the same way, their setpoints are less sensitive during sleep.

Depending on whether you are awake, asleep, or between, the setpoints that trigger your breath reflexes can change. The setpoints that trigger your breathing reflexes during sleep are not as sensitive to low oxygen or high carbon dioxide as when you’re awake.

This is because your body is less dependent on oxygen and your breathing is more shallow. Also, the air in your lungs is exchanging less vigorously. As you go from sleeping to waking, your setpoints change.

The setpoints can change even during sleep. REM sleep is characterized by a decrease in the sensitivity of breathing. It is possible to tolerate more carbon dioxide, and oxygen concentrations can drop very low during REM sleep before breathing reflexes are triggered.

Another factor that contributes to sleep apnea is the sensitivity of the setpoints.

Breathing Muscles

Breathing requires several muscle groups to be used in many places. These include the diaphragm (the intercostal and other muscles attached to the ribs), rib cage (the intercostal, rib and other muscles), the soft palate, tongue, upper and lower pharynx, the throat area behind your mouth, and the voice box (the larynx).

These muscles work together to ensure normal breathing. When you inhale, for example, your rib muscles contract and your tongue muscles stabilize your tongue position. Your soft palate muscles then become taut to keep your airway open.

Another factor that contributes to sleep apnea is the coordination of these muscle groups during breathing.


Snoring is when your soft palate vibrates (the back of your mouth). This can be caused by a variety of factors. During sleep, your soft palate and tongue muscle tone tend to decrease. They can become more relaxed and collapse together.

This can lead to snoring. Tonsils and the tongue can also produce sounds that alter or enhance the quality of snoring.

Snoring is affected by the position of the sleeper. Your tongue can fall toward your throat when you lie on your stomach. This will cause your airway to be blocked.

Snoring can also be caused by obstructions to your airway. You are more likely to snore when you have large adenoids, a large tongue, or your nasal passages become swollen due to allergies or colds.

Snoring can be caused by weight gain. This is because fat tissue builds up in the neck, which can narrow the airway.

Age can also play a role. Because muscle tone decreases with age, older people are more likely to snore.

After menopause, women are more likely to snore.

Snoring can also be aggravated by alcohol, certain medications, or physical exhaustion.

Sleep apnea is more than mere snoring. People snore even if they don’t experience the sleep-related interruptions and breathing problems that can be associated with sleep apnea. Although it isn’t a serious health risk, occasional or light snoring that doesn’t interrupt breathing can cause significant discomfort for a partner. Here are some solutions for occasional, harmless snoring:

  • You can sleep on your side. Asleep position monitor can be used to train you to sleep on your side.
  • Before you go to bed, avoid alcohol.
  • Talk to your doctor if you have any prescriptions or over-the-counter medications that may be aggravating your snoring.
  • Ask your doctor for an antihistamine if you have nasal congestion. There are also nasal strips that can be used to relieve congestion. These nasal strips can be purchased at pharmacies.
  • Reduce your body weight.
  • If necessary, the partner sleeping beside you can use soft foam earplugs. These earplugs are available at many pharmacies and industrial safety shops.

Simple Snoring can turn into sleep apnea

When the vibrations of the throat and tongue are accompanied by a variety of factors discussed earlier in this article, such as an instability in the breathing reflexes or a structural narrowing (for example, due to weight gain or enlarged tonsils), then snoring can turn into sleep apnea.

Sleep-disordered sleeping can be very severe and vary from person to person. Some people may experience snoring, which can be mild or occasional, that gradually becomes more severe and frequent, which could indicate sleep apnea.

This is often seen in adolescents when there is heavy snoring and, occasionally, brief apnea events. The picture can change gradually to more severe snoring and longer periods of nonbreathing. The pattern can become obstructive sleep apnea later in life.

This may lead to a longer period of nonbreathing and disrupted sleep patterns, as well as fluctuations in blood oxygen, daytime drowsiness, and a disruption in the structure of sleep. Even if you have never suffered from sleep apnea in your life, some people over 50 may experience a loss of muscle tone as a trigger for the development of sleep disorder.

It is possible for snoring to progress to sleep apnea in certain people, and you may end up needing sleep apnea surgery. This depends on all the factors that we have discussed here: breathing reflexes and the structure of the lungs, muscle coordination and inherited tendencies.


These are the most important aspects to sleep:

  • How much sleep do you get
  • Quality of sleep
  • The amount of rapid eye movement (REM) sleep
  • Sleep apnea can interfere with any of these.
  • Sleep apnea can be caused by an abnormality in the breathing reflex.
  • A loss of muscle tone in the throat and tongue can cause snoring.
  • The vibration of the soft tongue is responsible for most of the sounds associated with snoring.
  • It is possible to have snoring that doesn’t stop your breathing. These tips can help you reduce or eliminate snoring.

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