What Happens If You Stop Breathing in Your Sleep

Oxygen Levels Drop and Long-term Health Problems Develop

If you happen to be a firsthand witness, it can be a little scary to watch someone stop breathing during sleep. What happens if you stop breathing in your sleep? Why does it occur? Learn about some of the potential causes, including sleep apnea, and what short- and long-term consequences may occur.

When Breathing Stops in Sleep

Breathing disturbances can commonly be observed during sleep. The most frequently noted is snoring.

When the tissues of the upper airway vibrate during breathing, this causes the sound of snoring. It is also possible for breathing to completely stop, but what causes this?

Pauses in breathing during sleep are called sleep apnea, from the Greek for “no breath”. These events by definition last at least 10 seconds but they can last up to several minutes. Most often, this is due to obstructive sleep apnea (OSA). OSA occurs when the tissues of the upper airway – the tongue, soft palate, and uvula – collapse and disturb normal airflow. There may still be an effort to breathe, with the chest and abdomen moving, but air is not normally moving past the obstruction within the throat. As a result, airflow is reduced or is simply not observed to be moving through the nose or mouth during these periods.

There are other potential causes of disturbed breathing in sleep to consider. Less commonly, the breathing pattern may be abnormal due to a failure of the brainstem to stimulate breathing.

This occurs in central sleep apnea, Cheyne-Stokes respiration, and congenital central hypoventilation syndrome. The first two conditions may be present in heart failure, with narcotic use, or near death. The latter disorder is rarely present in some children at birth.

With improper breathing, the blood’s oxygen levels drop.

The brain’s sensors recognize that inadequate breathing is occurring, with increased carbon dioxide levels, and stimulates an awakening. This occurs with a burst of cortisol hormone. This stress response spikes the heart rate and blood pressure and can lead to other problems over the long term. The person experiencing it may wake up gasping or choking and an observer may witness a loud snort and movement of the body.

When Does Sleep Apnea Become Serious?

The severity of sleep apnea varies. It is thought to be normal for pauses in breathing to occur up to 5 times per hour in adults and once per hour in children. These events may even occur as part of normal sleep stage transitions. If breathing disruptions occur more frequently, sleep apnea may be diagnosed with a sleep study. The following categories are used to classify sleep apnea based on the apnea-hypopnea index (AHI):

  • Mild: 5-15 events per hour
  • Moderate: 15-30 events per hour
  • Severe: More than 30 events per hour

It is also important to recognize the degree of oxygen deprivation that occurs with these events.

When oxygen levels fall below 90%, this is called hypoxemia. In the setting of heart or lung disease, the oxygen levels may drop drastically with each apnea event. As a result, there can be a greater stress placed on the body overnight. Chronic oxygen deprivation may lead to both short-term and long-term effects.

What Are the Short-Term Consequences of Not Breathing in Sleep?

It is extremely unlikely that a single witnessed pause in breathing would be the last breath the person takes. Instead, the event is likely to end as described above. When apnea occurs chronically, it can lead to other health problems, but can it lead to sudden death?

Sleep apnea increases the risk of sudden death in sleep. It may provoke a cardiac arrhythmia that leads to an arrest of the heart’s function, called asystole. It can also lead to atrial fibrillation, heart attack (myocardial infarction), and even stroke. These events seem to increase towards morning, which is coincidentally when REM sleep occurs more commonly and when more sleep apnea is apt to occur.

These are singular events and sleep apnea itself is a disease that often lasts for years or even decades. Therefore, it is not necessary to become concerned over the consequences of one night of disordered breathing. It shouldn’t be dismissed as without consequence, however.

Chronic Risk with Disturbed Breathing in Sleep

Just like one cigarette won’t necessary lead to your demise from lung cancer, one night of sleep apnea may not spell disaster. However, smoking day after day, year after year will likely set you up for a grim end. A similar concern can be raised for untreated sleep apnea with cumulative detriments to health.

There is evidence that long-term sleep-disordered breathing can have important health consequences. It may increase the incidence of high blood pressure (hypertension), diabetes, and heart problems. It is associated with depression and memory problems like Alzheimer’s disease. It increases daytime sleepiness and may contribute to accidents. As mentioned previously, it can lead to heart attack, heart arrhythmias, and strokes. In short, untreated sleep apnea can kill you.

If you or someone you love experiences recurrent pauses in breathing, you should seek medical evaluation. Other symptoms or signs may point to the diagnosis, but a sleep study will give you a definitive answer as to the cause. Fortunately, there are effective treatment options available, including the use of CPAP or an oral appliance.

Don’t dismiss breathing disturbances in sleep as inconsequential; over time, serious problems can develop. Speak with your doctor and get the treatment you need to breathe and sleep better. You’ll be glad that you did.


Kryger, MH et al. "Principles and Practice of Sleep Medicine." Elsevier, 5th edition, 2011.

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