Buzz
Death is often considered the one certainty in life. But is it really? Merriam-Webster describes death as "a permanent cessation of all vital functions." Meanwhile, the Oxford English Dictionary narrows it down to "the permanent ending of vital processes in a cell or tissue." Yet, determining when a person is truly dead is more complex than it seems—the medical understanding of death has evolved over time and continues to change.
UNDERSTANDING DEATH
For much of history, doctors based their conclusions on simple observations to decide if someone had died. (This may explain the widespread fear of being buried alive and the extreme precautions people took to avoid it.) As Marion Leary, director of innovation research at the Center for Resuscitation Science at the University of Pennsylvania, explains, "If a person wasn't visibly breathing, and appeared cold and bluish, they would be deemed dead."
Over time, the criteria for determining death evolved. Prior to the mid-1700s, a person was considered dead when their heart stopped beating—this conclusion came from observing fatal events like decapitations, where the heart was often the last organ to cease functioning. But as our understanding of the human body advanced, organs like the lungs and brain began to be considered indicators of life or death.
This idea still holds to some extent today; you can be declared dead when your heart and lungs stop working. However, it’s also possible to be declared dead even if those organs are still functioning, but your brain is no longer active.
In many countries, being brain dead—where the entire brain ceases to function and cannot be restored—is the accepted definition of death, says neuroscientist James Bernat from the Geisel School of Medicine at Dartmouth College. "A doctor must demonstrate that the loss of brain function is irreversible," he tells Mytour. In some cases, a person might appear brain dead after an overdose or from hypothermia, but if the condition is temporary, they aren't truly brain dead.
In the United States, every state follows a version of the Uniform Determination of Death Act, which, in 1981, defined death as "an individual who has sustained either (1) irreversible cessation of circulatory and respiratory functions, or (2) irreversible cessation of all functions of the entire brain, including the brain stem."
However, this isn’t the final word on the matter. In two states, New York and New Jersey, families can reject the idea of brain death if it contradicts their religious beliefs. This creates a situation where a person could be considered alive in some states and dead in others.
A FADING DIVIDE
In earlier times, when one of the three vital systems—circulation, respiration, or brain function—failed, the others would typically follow within minutes, and there was no hope for recovery. However, thanks to advances in technology and medical treatment, this is no longer always the case. CPR can restart a heartbeat; a person who experiences cardiac arrest can often be revived within a 20- to 30-minute timeframe (in rare cases, individuals have been resuscitated after several hours). Since the 1950s, machines have taken over many of the body's critical functions. For instance, ventilators can keep air moving in and out of the lungs for those who stop breathing naturally.
Although impressive, these life-saving technologies have blurred the boundaries between life and death. "A person can now exhibit certain signs of life and others of death," says Bernat.
Individuals with severe, irreversible brain damage fall into this gray area. Many remain in intensive care units with ventilators assisting their breathing, yet due to their minimal reflexes or movements, they're still considered alive, particularly by their families. However, healthcare professionals may have a different view, sparking difficult and emotional debates over whether the person is truly alive.
Consider the case of Jahi McMath, a 13-year-old girl whose tonsil surgery in 2013 went horribly wrong, resulting in brain death—or so doctors believed. Her family rejected the notion of her death and transferred her from Oakland, California, to New Jersey, where she was kept on a ventilator and provided with feeding tubes. After months, her mother began recording videos showing Jahi moving parts of her body upon request. Further brain scans revealed that while parts of her brain stem were severely damaged, large portions of her cerebrum—responsible for consciousness, language, and voluntary movement—remained intact. Even her heart rate changed when her mother spoke to her, leading a neurologist to declare, after viewing several of the videos, that Jahi was technically alive—almost four years after being pronounced brain dead. According to her mother, Jahi celebrated her 17th birthday on October 24, 2017.
Organ donation introduces further complexities. Since organs must be transplanted quickly to prevent damage, doctors aim to declare death as soon as possible after disconnecting a person from life support. Typically, the standard is to wait five minutes after the donor's heart and breathing stop. However, some argue that this period is too brief, as the person could still potentially be revived.
Bernat, whose research spans brain death, the definition of death, consciousness disorders like coma and vegetative states, and ethical concerns in neurology, disagrees. "I would argue that breathing and circulation have permanently ceased even if they haven't irreversibly stopped," he asserts. "It won't restart on its own."
THE FUTURE OF REVIVING THE DEAD
As resuscitation technologies advance, scientists might discover new ways to reverse death. One promising method is therapeutic hypothermia. Often used with heart attack patients who have been revived, this therapy involves cooling the body, typically for 24 hours. "It enhances a patient's chance of recovering from cardiac arrest and the brain damage caused by oxygen deprivation," explains Leary, an expert in cardiac arrest, CPR quality, and therapeutic hypothermia research.
Another intriguing possibility, which gained attention in the early 2000s and still has supporters today, is cryonic freezing. In this process, dead bodies (or sometimes just heads) are preserved with the hope that future advancements in technology could revive them. Just moments after death, the body is cooled, a chest compression device called a thumper maintains blood circulation, and anticoagulants are injected to prevent clotting. Finally, the blood is replaced with a form of antifreeze to prevent the cell damage that usually occurs during freezing.
The notion is deeply controversial. "It makes for an interesting film plot, but it seems absurd to me," Bernat remarks. "I don’t think it’s the solution." However, even if cryogenics is off the table, Bernat is optimistic that some forms of brain damage, currently believed to be irreversible, may one day be treatable. "There’s considerable research underway at various medical centers focused on brain resuscitation," he adds.
Genetics offers another intriguing possibility. Scientists recently discovered that certain genes in mice and fish remain active after death. Even more surprisingly, some genes involved in regulating embryonic development, which deactivate when an animal is born, reactivate after death. It remains unknown if the same phenomenon occurs in humans.
