Let’s say you were to drop by any college campus, corporate office, or Providence Teachers’ Union meeting, pick an individual at random and profile their stress hormones. Now make your way to the savannah in Western Africa, intercept a gazelle trying to escape a hungry cheetah, and do the same. What you will find is that both bodies respond to stress in a very similar manner. That is to say, both utilize an evolutionary adaptation—stress—to combat what their brains have perceived to be imminent and life-threatening danger.
The effects of stress on the body and mind are puzzling—if anything, some people use it as a motivator. However, there is a lot of extremely prominent data supporting that prolonged stress not only damages your body, but could even explain the rise of diseases including obesity, adult onset diabetes, and heart disease in western society.
The easiest way to envision the stress response is to consider the scenarios leading to its evolution. For most of human existence, stress was completely different than it is now and more similar to the kinds of stress found in the rest of the animal kingdom.
For most animals, stress is a reaction to an “acute physical challenge”—in other words, the need to eat and the fear of being eaten. Disease is also a big stressor, and for some species the process of finding a mate can be stressful (think of a couple of male rams hashing it out on a steep mountainside).
But in the case of modern humans, the definition of a stressor has expanded to include the anticipation and mere idea of an actual stressor happening. For us, just the thought of something bad happening in the distant future is enough to send our bodies into stress-induced biological chaos.
In fact, “stress” as we know it today is almost exclusively a consequence of a truly stress-free world. In Western society especially, where the threat of immediate danger or starvation is generally absent, people seem to just find other things to get stressed about.
What it all comes down to is this: though the actual stressors affecting gazelles (acute, physical stressors) and humans (chronic, psychological stressors) are quite different, the biological stress response is basically the same. The main difference is duration—a gazelle may experience intense stress for a period, but then that switch goes off. For people who are consistently stressed, that switch might never go off completely.
The effects of long-term stress can only be determined by studying what actually happens in the body. On the most basic level, the brain propagates stressful messages to the rest of the body using the nervous system. Two specific parts of the nervous system are relevant here: one that’s responsible for the “fight-or-flight” response and another in charge of “rest-or-digest” functions.
The “rest-or-digest,” or parasympathetic component, is responsible for mediating the basic chores of maintaining the body: digestion, tissue repair, and growth. When you are sleeping or relaxing, the parasympathetic system is getting work done. By contrast, the “fight-or-flight” component, or sympathetic system, basically serves to divert resources to your muscles in times of perceived crisis.
These components work in opposition, and are effectively like the gas and brake pedals of your body. The sympathetic system increases heart rate while the parasympathetic system slows it down. Stress hits the gas on your sympathetic functions while throwing the brake on your parasympathetic functions.
In this example, the “gas” is a team of stress hormones—namely epinephrine, norepinephrine, and the glucocorticoids. Don’t worry too much about the names—the main thing to remember is that epinephrine and norepinephrine (adrenalin and noradrenalin) kick in immediately, inhibiting blood-supply to many of your organs so that more can go toward your lungs, heart, brain, and muscles (the “fight-or-flight” essentials). Glucocorticoids (types of steroid hormones) come on the scene later, and help divert energy towards fighting the stressor by upping your blood sugar and shutting down the immune system.
In the case of the gazelle evading the starved cheetah, the stress response is an elegant and logical solution. Who has the time to digest lunch and worry about reproducing some day when you might not live to see tomorrow? The answer is to shut those long-term projects down. But humans activate the same red-alert response on a constant, ongoing basis for stressors that are comparatively trivial. Over time, there can be severe consequences for ignoring those long-term projects.
The Heart of the Matter
The link between stress, personality type, and cardiovascular disease was first identified by an upholsterer. In the mid-1950s, Dr. Meyer Friedman and R. H. Rosenman ran a very successful cardiology practice, but were repeatedly burdened by one financial pitfall: reupholstering chairs.
For some reason, the chairs in their waiting room were being subjected to such a degree of wear and tear that they needed to be fully reupholstered on a monthly basis. One day, a new upholsterer came in to the clinic, took one look at the chairs, and said to Dr. Friedman “What the hell is wrong with your patients? People don’t wear out chairs this way.”
The upholsterer had inadvertently discovered that Type-A personalities visited the cardiovascular clinic more than average, although the actual “Type-A” phenomenon would not be formally acknowledged and linked to cardiovascular disease until years later. Type-A is characterized by “toxic hostility” resulting from the perception that, basically, the world is out to get you. Type-A people are impatient, aggressive, competitive, and tend to dislike waiting so much that they were wearing the lobby room chairs down just by way of their constant fidgeting. In other words, Type-A people are chronically stressed.
By the 1980s, studies showed that being Type-A is at least as big of a health risk as smoking and having high cholesterol.
Beyond the Type-A issue, these statistics imply something more general: stress is not good for your heart. Cardiovascular disease turns out to be the most well-documented and consistent consequence of chronic stress, regardless of your personality type. It also follows a relatively predictable course of action, and it all starts with being stressed out too much and too often.
When you start to feel stressed, epinephrine (adrenalin) pours into your blood stream and hits all kinds of nerve endings along the way, causing your blood pressure to skyrocket. You know the feeling—maybe you’re waiting in a grocery store line, about to miss your bus home, and there are five people ahead of you. Over time, these regular mini-crises add up: your blood vessel walls tighten up in attempt to control that high blood pressure (think of how much harder it is to control the flow of a fire hose than a garden hose), meaning that now your blood pressure is high by default. Tada! You’ve got chronic hypertension.
Meanwhile, your heart is also taking a beating from your high blood pressure, and your left ventricle, which receives blood, has to muscle up to deal with it. The result is left ventricular hypertrophy—a lopsided heart that struggles to beat regularly and is likely to give you a heart attack. In fact, statistics show that left ventricular hypertrophy is the best predicting factor for cardiac risk.
Like most people, you have probably been under the impression that arterial plaque is just the result of poor diet. These assumptions are incorrect.
When you have high blood pressure, your blood vessels start to fall apart. As the vessel walls become rough and inflamed from friction, they develop a Velcro-like attraction for any crap that happens to be in your bloodstream. The result is chunks of plaque choking up your arteries. It doesn’t help that stress makes your body dump even more crap (namely fatty acids and sugars—the Gatorade for your muscle tissues) into your bloodstream. If you’re really unlucky, one of these plaque balls can detach and wind up wedged somewhere it doesn’t belong, causing a stroke. A poor, high-cholesterol diet—which many mistakenly believe is the cause of arterial plaque—can certainly aggravate the situation, but stress has to do its damage first in order for plaque to form.
The 2010 report on United States health trends from the Center for Disease Control says it all: “In 2007, heart disease was the first leading cause of death and cancer was the second. One quarter of all deaths were from heart disease.” High on their list of morbidity risk factors were diabetes, hypertension, high cholesterol, and obesity, all of which have ties to a chronically stressed lifestyle.
Anxious Appetites (or Discomfort Food)
Anybody that has suffered from stress knows its effects on appetite. But that effect can vary from person to person—some people are prone to nausea and appetite loss (hypophagia), others may experience the alternate extreme of carb-cravings and binging (hyperphagia).
Both extremes make sense in the context of the stress response, and timing is especially important. Epinephrine (and norepinephrine) are the earliest on the scene and cause appetite loss. This also explains why stage fright can give you dry mouth, and why it’s easy to forego eating when you’re cramming for a final.
On the other hand, certain steroid hormones (glucocorticoids) are released later to motivate your body to replenish the energy stores it burnt up during its stressful period. These hormones drive your post-stress appetite for foods that are often high in simple sugars and fats for easy energy.
For still-unknown reasons, energy stores built after a stressful time tend to accumulate in a specific area: your gut. This visceral fat, which can lead to an “apple” body shape, happens to be a lot worse for you than fat deposited elsewhere because of its proximity—and obstructive potential—to your vital organs. Fat not caused by stress tends to go your bottom half, leading to a pear body-shape. It turns out that “apple-shaped” people are at high risk for cardiac disease, onset diabetes, and other stress-related diseases.
In this country, the general expectation is to work your ass off your whole life so you can get into a good school, then get a good job… you know the drill. Americans are hell-bent on making it big young, even if that means working 70 hour weeks just so we can retire at age 50. The sad thing is, by that point, the damage has been done. By that point, thank goodness you’re retired because it’s going to take a lot of time and energy to deal with your weakened heart and immune system, plus the diabetes, hormone imbalances and crappy demeanor you may have picked up along the way.
The good news is that it’s mostly preventable. Exercise is a big one, especially aerobic exercise done on a regular basis. In fact, a little exercise can improve your mood and fight off your stress response for up to a whole day after.
One surprising caveat about exercise is that it’s only a good stress-reducer if you want to do it. Studies of rats have shown their health to improve radically when they voluntarily run in a wheel, but take a turn for the worst when the rats are forced to do the same exercise.
It’s clear that stress is a huge detriment to health, both mental and physical. However, rather than locating your next gazelle like the hungry cheetah, human stress is often a reaction to some sort of societal demands. Rather than letting external pressure harm your heart and expand your waistline, take a load off and don’t let any waiting room chairs fall prey to your anxieties.
JITTANIA SMITH B’11.5 skyrockets her blood pressure every day.