Nearing the climax of any good horror flick is the inevitable drawn-out scene in a creaky, abandoned mansion. Tension builds as the moviegoers wait for the dreaded burst of fright: a ghostly hand emerging from behind a curtain or a knife-wielding attacker appearing from the shadows.
In the excitement, viewers probably don’t recognize changes in their own physiology. Heart rates increase, sweat forms on skin, pupils dilate, and even digestion is altered. Few may know their bodies are activating primitive survival systems developed over millions of years of evolution — systems intended, in the past, to protect humans from predators and other natural threats.
As important as these systems have been for humankind’s survival, there is a catch. This biological reaction, known as a catecholamine storm, puts stress on the body and, in very rare cases, can lead to heart failure. People literally can be scared to death.
The thrill of an amusement park ride, the fright of an auto accident, and the surprise of a police raid have all led to documented cases of heart failure thought to be caused by catecholamine storms. Even intense relief can trigger the reaction. In 1995, a man dropped dead in court after being acquitted of sexual assault. A year earlier, a golfer died after hitting a hole in one. Stress-filled times can also increase baseline heart risk: Researchers noted an uptick in hospitalizations for heart disease among New Yorkers exposed to the events of 9/11, for instance.
Dr. Martin Samuels, chairman of the Department of Neurology at Brigham and Women’s Hospital, has developed an expertise in this peculiar biological phenomenon. He noted, somewhat reassuringly, that in the general population, stress-induced sudden deaths are exceedingly rare, perhaps less than one per million per day. Still, he said, in an interview at his office, even if these people could be identified ahead of time, there is no obvious way to protect against them against this effect.
How did you become interested in studying this phenomenon?
I saw a patient during my internship at Boston City Hospital in 1971 who heard some bad news and then collapsed. There was some blood in the subarachnoid [spinal fluid] space and the electrocardiogram was extremely abnormal, suggesting that the stress and neurological problem had adversely affected the heart. At the time, the medical literature on the subject was very sparse, and no one knew how this could occur. I began to collect cases and went from there.
How did the human “fight-or-flight” system first evolve?
There’s a system in the brain, which protects the organism under severe life-threatening stress . . . the neurotransmitters are what we call catecholamines.
If we’re in the wilds of Africa and jaguars appear, this system would be activated. It’s completely involuntary. Your pupils would dilate. You would experience increased blood flow to the muscles and decreased blood flow to the gut and other less essential organs. Off you would run, or you could turn and fight.
How does that play out today?
In the modern world, if there is a catastrophe analogous to jaguars appearing, like 9/11 or a big earthquake or a giant fire or some other life-threatening catastrophe, the same primitive system is activated involuntarily, but there is no benefit. The benefit is lost, because it doesn’t increase your chance of survival.
How might this lead to sudden death?
There’s an abnormality of the heart that appears after an acute stress that was discovered with the invention of the echocardiogram. . . . It was discovered that, in people who had an acute life-threatening stress, their heart would suddenly dilate and function very badly.
Basically what we believe is that the cardiac problem is the most life-threatening problem, but that same pathophysiology, the same effect, happens in the other organs — in the gut, in the kidney, in the skin.
But I’m young and healthy. . .
You can be 11 years old with a normal heart and go to the amusement park on one of those really scary rides and drop dead. Now, it’s very rare. People will often ask me, “What should I do?”
OK, what should I do?
Well, that depends on your philosophy of life — what you think life is all about. Obviously, it’s not worth it to avoid everything, because then you run into other risks associated with being sedentary. But you have to be willing to accept the fact that high-risk activities that cause the catecholamine storm — the rush when doing certain things, like amusement park rides or surfing — can be dangerous. They aren’t usually dangerous, but it’s like being attacked by jaguars.
Interview has been edited and condensed. Ian Dillingham is a recent intern for Stat and an undergraduate studying neuroscience at the University of Michigan.