Everyone has heard stories of people dying “on the table” and being brought back to life—so-called near-death experiences. Descriptions of these events are remarkably similar from person to person, with several common themes: entering a tunnel with a bright light at the other end, having their entire life flash before them, seeing long-dead loved ones, experiencing a sense of separation from their body and floating above the action, perhaps as medical staff grab the paddles from the crash cart to try to get a pulse back (the “out-of-body experience”). Others tell of having vivid memories from long ago or just a feeling of peacefulness. Could there possibly be a scientific explanation?
Part of it, researchers are discovering, is that death appears to be not a moment but a process. Once cardiac arrest occurs and the heart ceases to work, oxygen-rich blood immediately stops being pumped to all the body’s tissues. Thus, theoretically, the brain, like all other organs, can no longer function. But an accumulating body of research suggests that brain cells continue to work for a short amount of time.
In a soon-to-be published study presented in November at the annual American Heart Association Scientific Sessions, researchers at New York University looked at electroencephalograms (EEGs) that measured electrical activity (brain waves) in almost 600 people at 25 hospitals who had experienced cardiac arrest and were undergoing CPR. Most of the patients died, despite the hospital setting. But the researchers found that even up to an hour after oxygen was no longer reaching people’s brains because their hearts had stopped, normal brain wave activity continued. That is, the patients’ brains “lived” after heart activity ceased. This was not a last-ditch, wild burst of electrical activity in the brain that was inconsistent with logical thought. It was near-normal brain activity like that seen during consciousness.
Of the 53 patients in the study who were “brought back to life” by CPR, 28 completed interviews about their near-death experiences. Eleven of those 28—about 40 percent—reported having “conscious” thoughts after their hearts had ceased working. They described having a sense of being separated from their body, observing the events without pain or distress, and evaluating the life they had lived, including their intentions and their thoughts toward others.
This study is not the first to find that brain waves continue after the heart stops beating. In a report from early 2022 in Frontiers in Aging Neuroscience, a man who had a subdural hematoma (a blood clot pressing on his brain) was undergoing an EEG to measure brain activity when he had a heart attack and died. For about 10 to 30 seconds both before and after his heart stopped, his brain had a surge in activity, specifically a surge in gamma waves, which are associated with consciousness, including memory. The investigators wrote that it is “intriguing to speculate that such activity could support a last ‘recall of life.’”
In another study, published in the Journal of Palliative Medicine in 2009, seven critically ill patients who had their life support withdrawn had a surge in brain activity that “approached levels normally associated with consciousness.” The researchers in this case, too, saw that the activity wasn’t an explosive, haphazard type of brain wave action but, rather, was consistent with higher-consciousness gamma waves. (Brain-dead patients do not tend to show such activity; it virtually always occurs in people whose hearts have stopped.) Other investigations have had similar results, indicating that the brain does not stop exactly when the heart does. “Time of death” appears to be something of an approximation.
Many questions are still unanswered. For instance, gamma waves can overlap with things going on in the body, like muscle activity. They might not all be related to awareness and thought. Also, all the studies included small numbers of people; it would be a stretch to draw broad implications. Then, too, no one has determined why near-death experiences seem to follow a pattern that repeats from person to person.
That said, people who “come back from” death often describe experiences that were pleasant, that put them at peace when it seemed like their life was over. They often recount a sense of memories and reconciliation. Perhaps the human body is designed such that death, rather than being the agonizing experience many suppose it to be, can allow for a sense of wellness as the mind slips away.
