People may die in their sleep for various reasons, with sudden cardiac arrest being one of the most common causes.
Other potential causes include conditions like congestive heart failure, stroke, and terminal illnesses such as lung failure.
Unexpected events such as seizures, drug overdoses, or carbon monoxide poisoning may also lead to death during sleep, sometimes without warning.
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Certain underlying health conditions, such as diabetes and obstructive sleep apnea (OSA), can increase the risk of dying in one’s sleep.
Diabetes-related issues, such as Dead in Bed Syndrome, may result from low blood sugar during the night, particularly in younger people with type 1 diabetes.
OSA can contribute to fatal events like heart attacks or strokes, and in rare cases, lead to asphyxiation.
Sudden Cardiac Arrest
Cardiac arrest occurs when the heart suddenly stops beating. Without immediate medical intervention, sudden cardiac death can happen within minutes. The risk of death is higher during sleep because emergency response times are typically too late.
Sudden cardiac arrest is one of the leading causes of nocturnal death. A 2021 study in Heart Rhythms found that approximately 22% of such deaths occur between 10:00 p.m. and 6:00 a.m. Several conditions, including heart attacks, arrhythmias, congestive heart failure, and stroke, can lead to sudden cardiac arrest.
Heart Failure
Heart failure is different from sudden cardiac death. With heart failure, where the heart struggles to pump blood effectively, death may occur many years after the initial diagnosis. In contrast, cardiac arrest, where the heart completely stops, can result in death within minutes.
Heart Attack
A heart attack, or myocardial infarction, happens when a blood vessel supplying the heart muscle becomes blocked, causing damage or death to the tissue. Severe heart attacks can lead to cardiac arrest and death. If blood flow to the brain is reduced, it can cause respiratory arrest, leading to death.
Arrhythmias
Irregular heart rhythms, known as arrhythmias, can disrupt the heart’s electrical system, causing the heart to beat too fast, too slowly, or erratically. These disruptions can lead to fatal conditions during sleep, including asystole (no detectable heart activity), atrial fibrillation, and various ventricular arrhythmias.
Congestive Heart Failure (CHF)
CHF can gradually lead to heart failure and, in extreme cases, cardiac arrest. Left-sided heart failure may lead to fluid accumulation in the lungs, respiratory arrest, and a complete loss of the heart’s ability to circulate blood. Symptoms indicating that someone with CHF is near the end of life include shortness of breath, fluid buildup, irregular heartbeat, and fatigue.
Stroke
A stroke occurs when a clot or rupture affects the brain’s blood supply. If a stroke involves the brainstem, it can impair breathing, consciousness, and motor control, potentially leading to death, particularly during sleep.
Respiratory Arrest
Respiratory arrest occurs when the lungs fail to exchange oxygen and carbon dioxide properly, leading to dangerously low oxygen levels and high carbon dioxide levels in the body. This condition can be caused by chronic respiratory diseases, including COPD, cystic fibrosis, and amyotrophic lateral sclerosis (ALS). In some cases, respiratory failure can lead to heart failure.
Type 1 Diabetes
For those with type 1 diabetes, fluctuations in blood sugar levels during sleep can result in unexpected deaths. “Dead in Bed Syndrome” refers to unexplained deaths in people with diabetes, often linked to low blood sugar, though the exact cause remains unclear. Younger individuals with type 1 diabetes are more likely to be affected by this phenomenon.
Carbon Monoxide Poisoning
Exposure to high levels of carbon monoxide due to faulty ventilation can lead to asphyxiation. Since carbon monoxide is undetectable by the senses, individuals may sleep through the early symptoms of poisoning, which include dizziness and shortness of breath. As the gas enters the bloodstream, it prevents oxygen from circulating effectively, leading to heart failure and respiratory arrest.
Medications
Certain medications, especially those used for pain management or insomnia, can suppress brain areas responsible for regulating breathing. Overdoses or combining these drugs with other depressants, such as alcohol, can lead to respiratory arrest. Drugs that may increase the risk include opioids, benzodiazepines, and sedatives.
Trauma
Severe brain trauma can also lead to sudden death during sleep. Symptoms like nausea or persistent headaches following a head injury may go unnoticed, and a brain hemorrhage can occur overnight, causing death. Though it’s generally safe to sleep after a concussion if evaluated by a healthcare provider, serious head injuries can still lead to fatal outcomes.
Choking
Choking is another potential cause of nocturnal death. This can occur if a person vomits during a nighttime seizure or after consuming alcohol, or if they accidentally inhale food or other objects while sleeping.
Epilepsy
A rare but significant cause of death in people with epilepsy is Sudden Unexpected Death in Epilepsy (SUDEP). This phenomenon may occur during or after a seizure, or even without any noticeable seizure activity. It is believed that SUDEP may be linked to interruptions in breathing or heart function during seizures.
Obstructive Sleep Apnea (OSA)
OSA is linked to several serious health conditions, such as heart attacks, strokes, heart failure, and arrhythmias, that may lead to sudden death. Though it is rare, OSA may cause fatal asphyxiation during sleep.
Other Sleep Disorders
Other sleep disorders, such as parasomnias (abnormal behaviors during sleep), can also be dangerous.
Sleepwalking, for instance, can lead to accidents, and REM sleep behavior disorder can result in falls or head trauma.
Awareness of sleep disorder symptoms, including excessive daytime drowsiness, snoring, and difficulty staying asleep, can help reduce the risk of dangerous outcomes.