What 'Dying in Your Sleep' Actually Means

Everyone's heard the phrase "dying in your sleep." But what does dying in your sleep feel like? Is it really peaceful, like Grandma's obituary said? What actually happens when someone dies in their sleep?

What dying in your sleep is actually like—i.e., what happens to the body, since we have no firsthand accounts—depends on the true cause of death, of which there are many. Science tells us that, yes, it is actually possible to die a seemingly painless death while remaining asleep.

But what are the facts behind the obituaries? What can actually cause you to die in your sleep? Read on to learn what the phrase really means.

  • You Died of Cardiac Arrhythmia

    You Died of Cardiac Arrhythmia
    Photo: Stephanie / Flickr

    Elizabeth Simpson, health reporter for The Virginian-Pilot, decided to investigate the phrase “died peacefully in his sleep” before including the phrase in her own father’s obituary in 2011. Simpson discovered that there is one condition that is most commonly the cause of someone dying in their sleep—and it turned out to be what technically killed her father.

    Here’s what Dr. Simone Gold, an ER doctor from California, told Simpson: "If a patient simply dies, without any symptoms, which of course we don't know unless it is witnessed, but when that is what occurs, absolutely and without question the most common reason would be a cardiac arrhythmia, specifically ventricular fibrillation or pulse-less ventricular tachycardia.” Basically, your heart starts to beat differently than it usually does, which leads to death.

  • You Died of Carbon Monoxide Poisoning

    Hearing that someone “died in their sleep” might also mean carbon monoxide poisoning. It’s called the silent killer for a reason: an entire family can fall asleep in a house with a carbon monoxide leak and just never wake up.

    The CDC says more than 400 Americans die this way each year. It warns that those who are “sleeping or drunk” can die before experiencing a single symptom of CO poisoning.

  • You Were Electrocuted

    Here’s a weird one: you could “die in your sleep” after being electrocuted. How? Dr. Patrick Lantz, a professor of pathology at Wake Forest University School of Medicine says the conditions would have to be just right. Let’s say there’s a faulty wire in a hairdryer.

    Lantz says touching that hairdryer in the bathroom late at night before going to bed could give off a shock, but an irregular heartbeat caused by that shock may not start that second:

    "It may give them enough time to lie down on the bed and fall asleep or fall down on the bed. They might not be found right next to the device that caused the electrocution."

  • You Died of Central Sleep Apnea

    Researchers at UCLA think a condition called “central sleep apnea” might be behind a lot of cases of elderly people dying in their sleep. It’s so sneaky it can go totally undetected, leading examiners to attribute heart failure as the cause of death instead.

    Central sleep apnea typically affects people older than 65 and is caused by losing brain cells that help control your breathing. Older folks with already weak hearts and lungs stop breathing during sleep because of a lack of those cells. They’re unable to rouse themselves naturally and they die from lack of oxygen.

  • You Died of Sudden Unexpected Nocturnal Death Syndrome

    Sudden Unexpected Nocturnal Death Syndrome, or SUNDS, is an obscure genetic condition that leads to cardiac arrhythmia. It strikes otherwise healthy people while they sleep—some in their early 30s—and it is prevalent in Southeast Asia. At one point in the early ‘80s, in fact, it was in the top five natural causes of death among the Hmong people, many of who resettled in the US after the Vietnam War.

    Dr. Shelley Adler, author of Sleep Paralysis: Night-mares, Nocebos, and the Mind-Body Connection, makes the controversial claim that the Hmong died in their sleep because of their belief in night spirits:

    It is my contention that in the context of severe and ongoing stress related to cultural disruption and national resettlement (exacerbated by intense feelings of powerlessness about existence in the United States), and from the perspective of a belief system in which evil spirits have the power to kill men who do not fulfill their religious obligations, the solitary Hmong man confronted by the numinous terror of the night-mare (and aware of its murderous intent) can die of SUNDS.

  • You Died of a Stroke

    A massive stroke can sometimes be the cause of “dying in your sleep,” but according to Dr. Leah Bush, former chief medical examiner of the state of Virginia, you usually would have experienced headaches or other nagging pain before you went to sleep. About one in seven strokes happen while you’re asleep, but they’re not all so-called “wake-up” strokes and are virtually indistinguishable from strokes experienced while awake.

    Elizabeth Simpson shared an anonymous journalist’s story about their mother dying of a stroke in her sleep at 82 in The Virginian-Pilot in 2011:

    She was physically active and mentally alert up until her final moment. She most likely thought warmly about her granddaughter's upcoming wedding when she went to bed that night. The TV in her bedroom was still on when her body was discovered the next morning. She was in bed leaning back against a pillow. The remote control was still in her hand.