Imagine a Cro-Magnon man out foraging for nuts and berries when he comes face to face with a sabre-toothed tiger. The stress is incredible. But early man is equipped with protective responses: Adrenalin soars, the heart races, eyes dilate. Stressed out, the man can run faster, hit harder, see better and think faster than he could seconds earlier. He raises a spear, considers the odds, and runs for his life.
Flash forward 25,000 years to the junior stockbroker, sneaking out for a coffee and muffin, when the boss suddenly appears with a stern look and a question: "Can you step into my office for a minute?"
The physiological and psychological response is much the same -- fight or flight -- but the office worker can't pummel his boss or make a dash for the street. The tension builds, but he locks it inside.
So whose stress is greater? It's a question that science, at a time of growing concern about stress in society, finds difficult to answer.
Cro-Magnon's threat seems greater, but once he's back in his cave he may not face another major trauma for weeks, while the stockbroker still needs to get into his car after being dressed down by his boss and battle commuter traffic, pay the bills and get the kids to soccer on time, before starting it all over again the next day.
"The stressors of modern life are very, very different from millennia ago, plus today we don't have any letup, but the basic physiological equipment we have to deal with them is identical," says leading stress researcher Tom Boyce, a professor of epidemiology at the Institute of Human Development of the University of California at Berkeley.
"The convention of evolutionary biology is that we've retained a number of reactions that are inappropriate to our lifestyles. At some point in our evolutionary past, we were hunted creatures and that kind of stress is unimaginable. On the other hand, the stress in a modern North American environment is not a piece of cake either. I'm just not sure they're comparable."
Charles Crawford, an evolutionary psychologist and professor emeritus at Simon Fraser University in Burnaby, B.C., says, "There is little doubt that we're a lot less stressed than the average caveman."
He feels that, despite our propensity for complaining about stress, the fact that modern humans are taller, heavier and live much longer than their ancestors is proof that life is easier. We also live in highly structured societies that offer protection against the most severe forms of stress: predation and starvation.
"Is the stress of an office job worse than hunter-gatherer stress? I doubt it," Dr. Crawford said. "Think of the Cree Indians living on the Plains 1,000 years ago. Life was harsh. If the buffalo didn't come, you starved. If the winter was too cold, you froze."
Peter Pope, an archaeologist and professor at Memorial University of Newfoundland in St. John's, says: "Whenever I have a toothache, I think: 'What did they do 500 or 1,000 years ago?' People lived with a lot of pain, and with the threat of disease."
On the other hand, the pastoral life was very cyclical and predictable. People had a place in society, and the economy was stable. "Even the Vikings who set out to raid and plunder travelled along well-established routes," Dr. Pope said.
"Day-to-day life was probably a lot less stressed. They had no cell phones, no TV, just cattle and crops to tend and long winters to tell stories. The only excitement was the occasional feast, and that was probably quite pleasant. Today we live in this sensory swamp, where we're constantly bombarded and we can never do anything unless it's an emergency. That's a lot more stressful than the Viking life."
Dr. Crawford concedes that today's stress may be worse, if only because it is relentless, not intermittent. "The fact that we've invented a word to describe the condition indicates that the problem is widespread, that there was a need classify how we were feeling."
The word "stress" is a relatively recent addition to the medical lexicon. It was coined in 1956 by Hans Selye, a professor at the University of Montreal, who became world-renowned with his research into "adaptation syndrome."
Dr. Selye was looking for a catchier term to describe the condition, and borrowed one from another discipline, engineering.
The engineering connection is apt because there is much evidence that stress, as we know it today, is something we have engineered into our lives. Humans have more than ample resources to live comfortable, simple, stress-free lives, but the quest for more material goods, for more comfort and power, is what brings stress to the fore.
Some of the more fascinating research in this area comes from Robert Sapolsky, a professor of biology and neurology at Stanford University who has studied Serengeti baboons for two decades.
The baboons live what is, in essence, a pastoral lifestyle, one that, on the surface, appears to be stress-free. They "work" whenever they want to, about four hours a day, to feed themselves. They have no predators and no bills to pay.
Yet they experience stress and stress-related diseases to almost the same degree as humans. The stress relates principally to their place in the social hierarchy. Those at the bottom of the pecking order -- the poor, if you will -- are sicker and die younger, and much of the stress comes from being unlucky in love and from disputes with fellow baboons.
As Dr. Sapolsky explains in his best-selling A Primate's Memoir,their lives are stressful because of the way they treat each other: "Basically, baboons have about a half-dozen solid hours of sunlight a day to devote to being rotten to each other. Just like our society. . . . We live well enough to have the luxury to get ourselves sick with purely social, psychological stress."
The reason that it is easier to study stress in baboons is that they are healthier and more monolithic than humans: They don't smoke, drink or drive cars, and they all have the same diet, one that leaves them lean. This allowed Dr. Sapolsky to find the links between personality and social status and stress. His research showed that baboon stress is entirely socially generated, like that of humans in Western society.
"Our stress is created by our privileged cocooning from ecological stressors; likewise, these baboons," he said.
Dr. Boyce said the work with baboons, like his work with humans, also shows that while we as a species have not evolved to the point where we have new mechanisms to deal with stress, we have adapted well to our stressful environment.
In other words, while everyone still has the flight-or-fight response embedded in the genes, individuals learn early in life to regulate it, to adapt to their personal circumstances. What has long intrigued Dr. Boyce, and driven his research, is the fact that a significant minority of the population still reacts strongly to stress.
"One of the answers is that, after millions of years of evolution, there are still advantages to being highly reactive," he said. "If you're driving down the highway at high speed and someone cuts you off, you want to have that instant, primitive reaction. This is not a set of systems that are there for nothing." SERIES HIGHLIGHTS - Friday: Stressed out and sleepless. - Saturday: Hidden curse of the young. - Today: Tension past and present. - Tomorrow: Anatomy of an ailment.
André Picard