Why Do People Die in Their Sleep?

Usually, when someone dies in their sleep, several codependent organ systems have failed. Most often, heart failure and lung failure are to blame. One one of these organs fails, the other likely will in short order.

Heart rhythm changes that trigger sudden cardiac arrest and the progressive loss of heart function associated with congestive heart failure (CHF) are chief among the medical conditions that can increase the risk of this occurring.

Also known as nocturnal death, dying in your sleep can also be due to unexpected event like a stroke, seizure, or a drug overdose. With an end-stage or terminal disease, dying in one's sleep is a possibility that may be anticipated.

This article explores the different reasons that people die in their sleep, including the factors that increase the odds of dying of heart failure in your sleep. It also describes the medical conditions that can contribute to the risk of sudden nighttime death.

Empty bed at night
Oktay Ortakcioglu / StockPhoto

Cardiac Arrest

Cardiac arrest is when the heart suddenly stops beating. Without immediate medical treatment, sudden cardiac death will occur within minutes. The risk of death is higher during sleep simply because the emergency medical response is usually too late.

Of all of the possible causes of nocturnal death (death while sleeping), sudden cardiac arrest is among the most common. Of these, roughly 22% occur between the hours of 10:00 p.m. and 6:00 a.m., according to a 2021 study in Heart Rhythms.

There are several medical conditions that can lead to sudden cardiac arrest, including heart attack, arrhythmia, congestive heart failure, and stroke.

Heart Attack

Heart attacks, also known as myocardial infarction, occur when a blood vessel supplying the heart muscle becomes obstructed and the tissue supplied is damaged or dies.

Myocardial infarctions may range from minor events that slightly compromise function to catastrophic blockages that lead to cardiac arrest and death.

A massive heart attack can reduce blood flow to the part of the brain that controls breathing, leading to respiratory arrest (the cessation of breathing).


The heart can also experience irregularities that impact its electrical system. The charge that is required to fire off the muscle in a synchronized fashion may become disrupted. The contractions may become irregular, too fast or too slow, and the heart’s pumping effectiveness may be compromised.

Arrhythmias may be a frequent cause of death during sleep. Asystole is a cardiac arrest rhythm when the electrical activity of the heart cannot be detected. Atrial fibrillation or flutter may undermine cardiac function.

Similar ventricular rhythms, including ventricular tachycardia, may become fatal. Cardiac blocks affecting the electrical pattern may also lead to heart dysfunction and death.

Congestive Heart Failure

Congestive heart failure may also gradually lead to the failure of the heart and, in severe cases, cardiac arrest.

Left-sided heart failure quickly impacts the right side of the heart, leading to fluid accumulation in the lungs and swelling in the feet and legs called peripheral edema. This can result in respiratory arrest. If the heart experiences volume overload, its ability to circulate blood may cease entirely.

Signs that a person with CHF is approaching the end of life include:

  • Shortness of breath with rest or minimal exertion
  • Extreme fatigue
  • Weakness
  • Pain
  • Persistent cough
  • Depression and anxiety
  • Constipation
  • Chronic nausea
  • Loss of appetite


Importantly, the heart may affect other systems that rely on its ability to circulate blood. Most notably, an irregular heart rhythm may lead to a clot that travels to the brain and causes a stroke. High blood pressure, or hypertension, may increase the risk.

If a stroke impacts the brainstem, breathing, eye-opening, muscle control, and consciousness may be compromised. These strokes may be fatal and can occur in sleep.

"A Peaceful Death"

If someone dies in their sleep, people sometimes regard it as a "peaceful" means of death. But, it doesn't mean that it is any less distressing to loved ones who are trying to wrap their head around the loss or understand what exactly happened. This is especially true if someone died unexpectedly.

Respiratory Arrest

At the most basic level, the lungs are responsible for the exchange of oxygen and carbon dioxide with the environment. When they do not function properly, oxygen levels fall, carbon dioxide levels rise, and dangerous changes in the acid-base balance of the body can occur.

When the imbalance is critical enough, respiratory arrest can occur. This can also place excessive strain on the heart and cause it to progressively fail.

Respiratory failure may occur due to chronic, degenerative disease. This can be the failure of the lungs themselves, such as in:

  • Chronic obstructive pulmonary disease (COPD)
  • Cystic fibrosis
  • Emphysema
  • Lung cancer
  • Pneumonia
  • Pulmonary embolus (clot to the lungs)
  • Pulmonary fibrosis
  • Status asthmaticus

It is also possible for the lungs to fail due to changes in the muscles or nervous systems, such as with amyotrophic lateral sclerosis (ALS or Lou Gehrig’s disease) or myasthenia gravis.

There are even congenital disorders that affect the ability to breathe like congenital central hypoventilation syndrome. Sudden infant death syndrome (SIDS) represents a failure to breathe normally during sleep.

When death approaches slowly, a characteristic pattern of breathing—called Cheyne-Stokes respiration—occurs. Often noted in heart failure, narcotic medication use, and injury to the brainstem, it may indicate imminent breathing cessation and death. Consciousness may become depressed as the affected person slips away.

Toxins and Poisons

In some cases, death at night may occur due to toxins or poison.

For example, carbon monoxide poisoning from faulty ventilation may cause death by asphyxiation. A similar thing can occur when inhaling recreational drugs like"poppers" (amyl nitrate, butyl nitrate) or "laughing gas" (nitrous oxide), both of which can trigger irregular heartbeats and sudden cardiac arrest (typically in those with an underlying heart condition).

Certain medications used to treat pain and insomnia may increase the risk of death by depressing (suppressing) parts of the brain that regulate breathing. This is common when a drug is overdosed or combined with other depressants, including alcohol.

The drugs most likely to cause respiratory arrest when overused include:

  • Amphetamines like methamphetamine and Ritalin (methylphenidate)
  • Benzodiazepines like Valium (diazepam) and Xanax (alprazolam)
  • Cocaine
  • Opiates like fentanyl, morphine, OxyContin (oxycodone),
  • Sedatives like Ambien (zolpidem) and Ultram (tramadol)


Severe brain trauma can also cause sudden death, often while a person is sleeping. Sometimes symptoms like nausea, persistent headaches, and dilated pupils may go unrecognized or be dismissed following a head injury.

In an effort to "sleep off" the symptoms, a person may experience a brain hemorrhage (bleed) during the night and die.

According to the Brain Trauma Foundation, traumatic brain injury (TBI) contributes to around 30% of all injury deaths in the United States.


It is also possible to choke to death while sleeping. This can occur if a person vomits during a nighttime seizure or after too much alcohol.

It can also happen if you fall asleep with food or a throat lozenge in your mouth and accidentally inhale it.

The Role of Sleep Disorders

It is possible for death in sleep to occur due to a few other disorders, including some sleep conditions. In particular, seizures may be fatal. There is a condition known as sudden death in epilepsy (SUDEP) that is not fully understood.

Obstructive sleep apnea (OSA) may exacerbate other medical conditions that may ultimately be fatal. These include strokes, heart attacks, heart failure, and arrhythmias that can all result in sudden death. Though unlikely, it is also possible for OSA to cause fatal asphyxiation, or choking.

It is possible to die from sleep behaviors called parasomnias. Sleepwalking can lead someone into dangerous situations, including falling out of windows from upper floors, off a cruise ship, or wandering onto the street into traffic. “Pseudo-suicide” describes fatalities among people with sleepwalking injuries who die without known depression or suicidal ideation.

REM sleep behavior disorder may lead to a fall out of bed and head trauma in sleep. This could cause an internal hemorrhage; an epidural hematoma can quickly prove deadly.

Even if the sleep disorder is not immediately fatal, there is evidence that insomnia increases the risk of suicide. Chronic sleep deprivation may increase overall mortality after years of poor sleep.

In order to avoid dying in the night from a sleep disorder, be aware of other symptoms (including insomnia and early morning awakenings) or signs of sleep apnea (pauses in breathing, snoring, nocturia, bruxism, excessive daytime sleepiness, mood, and cognitive problems, etc.). Fortunately, sleep disorders are treatable. Optimize your overall health and don’t forget the important role of healthy sleep.

Frequently Asked Questions

  • Are there signs you may die in your sleep?

    According to the Hospice Foundation of America, there are several signs that a person with an end-stage illness is near death. A few include:

    • Gaps in breathing, noisy breathing, or coughing
    • Decrease in body temperature, pulse, blood pressure, and respiration
    • Purplish or grayish color discoloration, particularly on the hands and feet
    • Increased pain with moaning or groaning
  • Is it painful when you die in your sleep?

    It depends on the cause. If there is a major event like a massive stroke or ruptured aneurysm, the pain may be severe enough to rouse someone from their sleep. But, with certain terminal illnesses or events like a drug overdose or carbon monoxide poisoning, the decline in organ function may be so gradual that the person remains unconscious and dies "peacefully."

  • How quick is death from heart failure?

    Heart failure is not the same thing as sudden cardiac death. With heart failure, in which the heart is less able to pump blood efficiently, death may come many years after the diagnosis. With cardiac arrest, in which the heart altogether stops, death can come in minutes.

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Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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Additional Reading
  • Jeyaraj D, et al. “Circadian rhythms govern cardiac repolarization and arrhythmogenesis.” Nature. 2012. doi:10.1038/nature10852

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By Brandon Peters, MD
Brandon Peters, MD, is a board-certified neurologist and sleep medicine specialist.