Getting Our Minds Around the Physical Nature of Deadly Stress
At least a few times in their lives just about all people have personally struggled with headaches, high blood pressure, malaise, or even more serious symptoms of stress. Despite the physical debilitation, there’s still this notion that stress is “just in the mind.” Somehow, it’s not really real. It’s a bit like the old doctors who didn’t think athletes were really injured unless there were was blood to stanch or a bone to set.
We discuss the power of attitude—both positive and negative — to directly affect health in our book Maximum Brainpower: Challenging the Brain for Health and Wisdom. And there’s no doubt of the mind’s ability to influence the impact of stress. Paradoxically, this fact reinforces the supposition that stress is not “real” the way that out-of-control cell reproduction or plaque accumulation in the arteries is real.
Though in many ways it is perceptual, stress is a biological response to change — to the unknown — and it has very direct and powerful biological consequences. These biological changes are as real as any of the many modern diseases that stress contributes to — including cancer and heart disease.
We were reminded of the tight connection between stress and biology in a recent study by Yale University researchers, which was published in Science magazine and reported in the Los Angeles Times. In an experiment, one group of grasshoppers was tormented by being enclosed with spiders. The grasshoppers didn’t know that the spiders couldn’t hurt them — the spiders’ mouths had been glued shut. Meanwhile, a control group of grasshoppers merrily lived in unstressed isolation.
After the grasshoppers died and the remains were ground up, the scientists discovered that the soil containing non-stressed grasshoppers was better able to break down plant matter than the soil that contained the stressed grasshoppers: Ultimately, “unstressed soil” had more nutrients. Stress changed the biology of the insect — and thus, the biology of the earth!
Stressed insects had a higher metabolic rate, which caused them to eat more carbohydrates and less protein. Less protein meant fewer enzymes to break down plant matter. Under stress, the bugs ate the entomological equivalent of junk fund.
If stress can have this kind of effect on an insect, what kind of effect will it have on a far more complex biological system known as the human body? Even more detrimental, as it turns out. Chronic stress damages the immune system, especially lymphocytes, the white blood cells that are our bodies’ first line of defense against viruses, bacteria, mold, and other pathogens.
High-stressed women with breast cancer suffer a 15.4 percent greater breakdown of white blood cells that attack invaders, than low-stressed women, according to Ohio State University. High-stressed women also have a 20.1% reduction in their response to gamma interferon, a natural substance in the body that enhances white blood cell activity, and have a 19.8% lower response by T-cells, another infection-fighting cell. Stress increases the odds of bacterial infections such as tuberculosis and strep throat, and substantially worsens reactions to allergies. Stress is implicated in the onset of depression and Alzheimer’s and other degenerative brain diseases.
Cortisol, the primary stress hormone, appears to be the main culprit. Acute stress actually increases the number of white-blood cells, and cortisol readies the heart, lungs, and muscles for action, reduces bleeding, and promotes healing. But in chronic, long-term stress, cortisol suppresses the immune system, promotes the production of “bad” cholesterol, and damages the hippocampus region of the brain, which harms memory and increases the likelihood of an overstressed reaction in the future.
Stress also impairs cognitive function. Studies by Stanford, Vanderbilt, and the University of London have shown that multitasking in various guises will impair memory and the ability to translate learning in one context to learning in another — one of the fundamental definitions of intelligence. Stanford researchers were shocked to discover that prototypical Silicon Valley multitaskers were bad at just about every mental task. They were far more distracted by irrelevant items, they had worse memories, and they were slower at switching tasks (!) than non-multitaskers.
Efforts to multitask are thwarted by the brain’s basic mechanisms. Learning a task through sustained concentration fires up the hippocampus. Learning a task while distracted causes the memory to form in the striatum, which does not require much effort, is related to very specific tasks, and is not easily transferred to new situations. Constant efforts to task-switch also release cortisol and adrenaline, which hamper the formation of short-term memory.
Multitasking is a microcosm of the change and stress inherent in modern life.
“Good stress” (eustress) and bad stress are not different kinds of stress but different levels. Too much stimulation and the body is overwhelmed. Too little stimulation and the body also has a stress reaction. Eustress is Goldilocks’ stress — neither too much nor too little. It’s just enough stress to stimulate performance but not enough to break us down.
Whole volumes have been written about both kinds of stress and, in particular, how to deal with bad stress. In Maximum Brainpower, we spend several chapters on stress and, like others, offer strategies on reducing stress. Behind all approaches to stress, though, must be two fundamental concepts.
The first is that human beings stress is the body’s response to potential danger. Biologically, we are still hunter-gatherers. We are wired to deal with immediate and potentially fatal danger. Will that creature over there eat us, or can we eat it? Can we outrun the forest fire or ford the raging river? Until the last hundred years very few people lived long enough for chronic stress to kill them.
But: All of the hassles at work trigger the same threat response as physical aggression or another bodily threat. If the brain perceives “danger” — real or psychological, it does not matter — it pumps stress hormones into the system. We have no biological defenses against the year-after-year grinding stress of modern society.
The second, and perhaps most important, insight is that stress is not “psychological.” Stress is a biological response that creates biological damage. Stress is not something we should just “deal with,” as in tolerate. Nor is alleviating stress about “feeling good” psychologically. It is about restoring the chemical balance inside us. Just as an unstressed insect nourishes the soil, the unstressed mind nourishes the body’s internal ecosystem.
If someone told us that an abnormal Pap smear or PSA result was just “psychological,” how aggressive would we be seeking treatment? Like these other tests, stress is a flashing red danger sign that our internal biology is seriously out of whack. By correctly perceiving stress as a biological problem, we are far more likely to get the proper treatment now, rather than continuing to just “deal with it.”
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