Sleep / Editorial

What happens to our breathing during sleep?

Introductory · 8 min read · ■■■□ moderate evidence

During the day we can hold our breath or speed it up if we want. Once we fall asleep, the brain takes over completely. All night, without our noticing, we keep breathing in and out. Most nights this happens quietly. On some nights, though, something changes in the throat: snoring starts first, and sometimes breathing stops altogether for a while.

In this article we explain from the beginning what happens to breathing during sleep, which of it is harmless, and what deserves attention.

Breathing through the night

Sleep is not one long stretch. A night is made of cycles that each last 80 to 100 minutes, and there are usually four to six of them¹. In each cycle we move from light sleep into deep sleep, then into REM sleep, when most dreams happen. In REM the muscles go slack and stay still, and this stage gets longer towards morning¹.

It is not only the arms and legs that relax. As we fall asleep, the muscle in the tongue relaxes too: in one study of this muscle, about half of the nerve cells that fire with each breath fell completely silent at the moment of falling asleep⁷. This is why, in some people, breathing problems are worst in REM sleep, in the early hours of the morning⁸.

The three states of the throat

Part of the passage from the nose to the lungs is not surrounded by bone: the soft palate, the base of the tongue and the walls of the pharynx are flexible tissue (Figure 1).

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1. Nasal cavity. Most breathing comes in here. The air is warmed and moistened on the way.
2. Hard palate. The bony front part of the roof of the mouth. It does not move during sleep.
3. Soft palate. The flexible, muscular part behind the hard palate, with the uvula at its tip. One of the tissues that vibrates in snoring.
4. Tongue. A large mass of muscle. Like the other muscles, it relaxes during sleep.
5. Tongue base. The back of the tongue, facing the throat. It can slide backwards when you lie on your back and the muscles relax.
6. Pharynx. The passage for air coming from the nose and mouth. This is where the airway narrows during sleep.
7. Back wall of the pharynx. The wall in front of the spine. When the airway closes, the soft palate and tongue base rest against it.
8. Epiglottis. The flap that covers the entrance to the windpipe when you swallow.
9. Hyoid bone. A small bone that the tongue and throat muscles attach to.

When the muscles relax, this soft section narrows a little². The narrowing has three states (Figure 2):

• Airway open. Air passes quietly. This is quiet breathing.
• Airway narrowed. Air rushing through the narrow gap makes the soft tissues vibrate. The sound of that vibration is snoring.
• Airway closed. No air gets through. The chest and belly keep trying to breathe, but no sound comes from the mouth or nose. This is called apnea. The brain restarts the muscles with a brief awakening; that deep, rasping first breath is the moment it happens².

Airway openAir passes quietly.

Airway narrowedThe tongue base and soft palate slide back; air rushing through the narrow gap makes the tissues vibrate.

Airway closedThe soft palate and tongue base rest against the back wall; no air passes and the sound stops.

These awakenings are usually not remembered in the morning. The person thinks they slept through the night, but their sleep was broken up again and again.

Snoring does not mean being ill

Snoring is very common. In a nationwide study of 5,021 adults from every region of Türkiye, one in ten (9.6%) said they snored almost every night³. In most of these people, breathing does not stop. The classification used by sleep physicians does not count snoring on its own as a disease either; it lists it among the "normal variants"⁴.

So there is no need to panic because the person next to you snores. What is worth listening to is not the sound itself, but the gaps in it.

The real sign: silence

It is three in the morning. The person beside you is snoring; a steady sound you have been used to for years. Then the sound suddenly stops. The room is quiet. One, two, three seconds. Five. Ten. Then a deep, rasping breath, and the snoring carries on where it left off.

Most people do not notice that silence, and those who do usually think "well, it passed". Yet this may be the moment the airway closed completely. In sleep apnea the airway closes tens, sometimes hundreds of times a night. Doctors measure it by how many times it happens per hour. Worldwide, about 936 million people aged 30 to 69 are estimated to have mild or more severe sleep apnea, and 425 million of them moderate or severe sleep apnea⁹. In the study from Türkiye, 13.7% of adults came out as high risk for sleep-disordered breathing³.

Most people do not know this, because they cannot hear their own sleep. A study in the United States estimated that 93% of women and 82% of men with moderate or severe sleep apnea had not been diagnosed¹⁰. These figures are from the 1990s¹⁰; we could not find a newer large study that answers the same question today. But the core of the problem has not changed: apnea is usually noticed not by the person sleeping, but by the person next to them.

Not every silence is apnea. The person may have turned over, closed their mouth or settled into quiet breathing. That is why a single night of listening is not enough to decide. What matters are long, repeated silences: longer than ten seconds, ending in a deep gasp, and coming back again and again through the night.

What can sound tell, and what can it not?

A phone microphone hears snoring well. In a study that tested three snoring apps in a sleep laboratory, the snoring the apps counted agreed with what the laboratory counted¹¹. A model trained on home recordings estimated the share of the night spent snoring almost exactly as the experts had marked it¹².

Telling from sound alone whether breathing has stopped is harder. A pooled analysis of eleven studies on phone-based sleep apnea screening found that methods relying on sound alone caught most people with apnea, but were less good than methods measuring movement and oxygen at telling apart people without apnea⁵. An international expert group also did not consider sound alone enough to grade how serious snoring is¹³.

In short, sound is a good clue, not a diagnosis. Sleep apnea is diagnosed with a sleep test, done in a laboratory or at home⁶.

When to see a doctor?

We have gathered what you can bring and what you can ask when you see a doctor on a separate page.

What can you do tonight?

If someone next to you snores, listen to the silences and make a note: roughly how many seconds they lasted, how many times they happened in the night, whether the person was lying on their back, and whether each one ended with a deep gasp. When you talk to a doctor, these few lines say far more than "they snore a lot".

If you are the one snoring, look at what makes it worse. Sleeping on your back, alcohol and late meals in the evening, weight and a blocked nose can all make snoring worse. We also look at which remedies work and which are only popular on social media, with sources, in the Myth or fact? column.

If you are curious, you can listen to clips from real sleep laboratory recordings to hear what snoring and pauses in breathing sound like.

In depthmechanisms, studies, limitations

Pathophysiology. Obstructive sleep apnea does not have a single cause. A narrow or easily collapsible upper airway is the basic predisposition; it is accompanied, in varying proportions, by an insufficient dilator muscle response during sleep, a low arousal threshold and an oversensitive ventilatory control (high loop gain)². Snoring is the vibration of the soft palate, uvula and tongue base in the partly collapsed segment; most events end with a cortical arousal, and sleep becomes fragmented².

Site of collapse. Collapse can occur behind the soft palate, behind the tongue base, or at both; its site and pattern differ between people². Below is the sound of the same three states, recorded above the bed in a sleep laboratory. In the spectrogram each breath shows up as a vertical band; in apnea the bands stop within the intervals marked by the expert.

ABC

• A. Retropalatal region: velopharynx; between the velum palatinum and the posterior pharyngeal wall.
• B. Retroglossal region: oropharynx; between the radix linguae and the posterior pharyngeal wall.
• C. Epiglottis: the flap over the larynx.

• Airway open: quiet breathing

  

• Airway narrowed: regular snoring

  

• Airway closed: recurrent obstructive apnea

  

  obstructive apneaobstructive apneaobstructive apnea

Definition and thresholds. According to ICSD-3-TR, a diagnosis of OSA requires at least 5 predominantly obstructive respiratory events per hour on PSG or HSAT together with symptoms or an associated condition, or at least 15 events per hour regardless of symptoms⁴. Under the AASM rule, a hypopnea is scored as a 30% reduction in airflow accompanied by a 3% desaturation or an arousal¹⁴; in centres using the 4% rule, the AHI of the same night comes out lower, and this difference is not evenly spread across age groups¹⁵.

Prevalence. In the Swiss HypnoLaus cohort (aged 40 to 85), an AHI of 15 or more was found in 49.7% of men and 23.4% of women¹⁶. A literature-based global estimate projects 936 million mild or worse and 425 million moderate or severe cases between the ages of 30 and 69⁹. In TAPES (Türkiye, n=5,021), high risk on the Berlin questionnaire was 13.7% and habitual snoring 9.6%; because it is questionnaire based, this is not PSG-confirmed prevalence³.

Performance of acoustic methods. In a meta-analysis of eleven studies (AHI 15 or more), the pooled sensitivity of phone-based methods was 0.91 and the specificity 0.88. In the sound-only subgroup (5 studies), sensitivity held at 0.88 while specificity fell to 0.81; in the movement-based subgroup specificity was 0.96⁵. A deep learning model tested per person on home recordings reported r=0.97 agreement for the snoring ratio¹². In commercial apps, agreement between snore counts and PSG is good, while the relationship with AHI is moderate and varies by app¹¹. There is no consensus on the definition, thresholds and microphone position for objectively measuring snoring¹⁷.

Guideline. The AASM diagnostic guideline recommends that questionnaires and clinical prediction tools not be used to diagnose OSA without PSG or HSAT. In a patient with excessive daytime sleepiness plus at least two of habitual loud snoring, witnessed apnea or gasping or choking, and diagnosed hypertension, the likelihood of moderate to severe OSA is high; such a patient should have PSG or a technically adequate HSAT⁶.

Limitations. The most often cited estimate of the share of undiagnosed disease dates from 1997 and comes from a sample of employed adults in the United States¹⁰; there is no current, population-based, PSG-confirmed counterpart. We could not find national prevalence data for Türkiye measured with PSG.

@misc{nefesly2026whathappenstoourbreathingduringsleep,
  author = {{Nefesly}},
  title = {What happens to our breathing during sleep?},
  year = {2026},
  howpublished = {\url{https://nefesly.com/en/guide/what-happens-to-our-breathing-during-sleep/}},
  note = {Last updated 2026-10-29; accessed 2026-10-30}
}