Scientists Monitored 631 People As They Died. This Is What They Found

The largest international study of the physiology of death to date shows that death is “more of a continuum than the flipping of a switch.”
Scientists Monitored 631 People As They Died. This Is What They Found
Image: Siqui Sanchez via Getty

The living have always worried about the dead coming back to life. It’s the plot of the New Testament, the reason 19th century families installed bells in their loved one’s coffins, and a source of tension in end-of-life care today.

While doctors work to reassure families holding vigil in intensive care units and hospice facilities that the end has indeed come, death remains something of a mystery—even among medical researchers. 


These unresolved questions around things like brain death, cardiac death, and more have led to the proliferation of “myths and misinformation,” said Sonny Dhanani, chief of pediatric intensive care at the Children’s Hospital of Eastern Ontario. 

“We felt [stories about the dead coming back to life] might have been impacting people’s motivation to consent for their loved one to be a donor, and for the medical community to offer, donations,” he said. “We wanted to provide scientific evidence to inform the medical understanding of dying.”

In a new study, published Thursday in the New England Journal of Medicine, Dhanani and his team report the results of the largest international study into the physiology of dying to date. It suggests the living can rest easy, kind of. 

Between 2014 and 2018, the researchers observed the heart function of 631 patients in 20 adult intensive care units in Canada, the Czech Republic, and the Netherlands after they were taken off life support. The scientists found that 14 percent of the dead showed some flicker of cardiac activity—measured by the electrical activity of the heart and blood pressure—after a period of pulselessness. 

But the doctors at the patient’s bedside never got a determination of death wrong. “No one lived. Everyone died. No one actually came back to life,” Dhanani said. 


The sputtering was short-lived—the furthest cardiac activity came just 4 minutes and 20 seconds after their heart initially stopped beating—and not strong enough to support other organs, like the brain. 

The data “help us understand how to medically define death, which is more of a continuum than the flipping of a switch,” according to Joanna Lee Hart, a pulmonary and critical care physician and assistant professor at the University of Pennsylvania’s Perelman School of Medicine.

“Our bodies are physiologically designed to stay alive… As our bodies try to keep us alive, they will pump out natural chemicals to sustain life as long as possible,” Hart wrote in an email to Motherboard. But, she added, “Once the dying process starts, it is very hard to return a person's body back to a condition where the person can survive.” 

This should be comforting to families and medical providers. Among other things, the research affirms that current practices, which typically tell doctors to wait 5 minutes after the pulse stops to name a time of death, are working. At that point, things like organ retrieval are safe to start. 

While there are still plenty of questions about death, dying, and the afterlife, this study—which is unlikely ever to be repeated, given its scope—is something close to the definitive word on the question of the post-mortem cardiac activity.

“Determining death is so emotional to everyone,” Dhanani said. “We hope that rigorously studying death and dying, not being afraid of that conversation, will help.”