The "fight or flight response" is our body's primitive, automatic, inborn response that prepares the body to "fight" or "flee" from perceived attack, harm or threat to our survival.
Our fight or flight response is designed to protect us from the other wild carniverous animals, like Tigers, Devils and Bears, threatening our physical survival. At times when our actual physical survival is threatened, there is no greater response to have on our side. When activated, the fight or flight response causes a surge of adrenaline and other stress hormones to pump through our body. This surge is the force responsible for mothers lifting cars off their trapped children and for emergency workers and trauma teams saving endangered victims. The surge of adrenaline gives us that burst of energy to survive and courage at times when we are in grave danger.
Unfortunately the survival system of fight or flight has not exactly adapted to modern day living. Today the wild animals we encounter are not a threat to our physical survival. The perceived dangers of today consist of rush hour traffic, missing a deadline, bouncing a check or having an argument with our boss or spouse. Nonetheless, these modern day, wild animals trigger the activation of our fight or flight system as if our physical survival was threatened. On a daily basis, toxic stress hormones flow into our bodies for events that pose no real threat to our physical survival.
When our fight or flight system is activated, we tend to perceive everything in our environment as a possible threat to our survival. By its very nature, the fight or flight system bypasses our rational mind—where our more well thought out beliefs exist—and moves us into "attack" mode. This state of alert causes us to perceive almost everything in our world as a possible threat to our survival. As such, we tend to see everyone and everything as a possible enemy. Like airport security during a terrorist threat, we are on the look out for every possible danger. We may overreact to the slightest comment. Our fear is exaggerated. Our thinking is distorted. We see everything through the filter of possible danger. We narrow our focus to those things that can harm us. Fear becomes the lens through which we see the world. We are most likely to experience this when we are exhausted.
The evidence is overwhelming that there is a cumulative buildup of stress hormones. If not properly metabolized over time, excessive stress can lead to disorders of our autonomic nervous system (causing headache, irritable bowel syndrome, high blood pressure and the like) and disorders of our hormonal and immune systems (creating susceptibility to infection, chronic fatigue, depression, and autoimmune diseases like rheumatoid arthritis, lupus, and allergies.)
Here’s what happens to our organs and biochemistry when we’re stressed out . . .
The stress response begins above your shoulders. The amygdala (a cluster of cell nuclei inside the temporal lobe that processes emotional data) sends a threat message to the hypothalamus, which in turn tells the sympathetic nervous system to protect you from attack. The nervous system increases heart rate, constricts some blood vessels and dilates others, slows down the intestines, inhibits digestive secretions, and prompts glands to flood the system with cortisol.
If this alarm is set off too often, it can do serious physical damage. “When too much cortisol is hitting the brain for an elevated amount of time,” Lucille says, “you start to create something called hippocampal brain damage, and the results of this are disturbed circadian rhythms: Your sleep-wake cycle is disturbed. You get moody, and you get memory loss, brain fog.”
The Pituitary Gland
Sometimes called the “master gland,” the pituitary controls most of the other glands in the body, regulating a host of functions including body temperature, thyroid activity and urine production (hence those sweaty palms and frequent bathroom trips when you’re nervous). During the stress response, the pituitary produces adrenocorticotropic hormone (ACTH), which prompts the adrenal glands to produce cortisol. Cortisol increases arterial blood pressure, pulling glucose and fat from body tissues into the bloodstream for energy, one reason appetite diminishes during acute stress.
The pituitary gland also releases thyroid-stimulating hormone, which stimulates the thyroid gland to produce thyroxine. Thyroxine increases the metabolic rate, raises blood-sugar levels, and increases respiration, heart rate and blood pressure — all essential to a quick burst of activity. But the metabolic boost from thyroxine uses up nutrients too quickly, so the body overuses B vitamins and excretes calming magnesium.
Blood vessels constrict during the stress response, which makes it harder for the heart to pump blood. High blood pressure from constricted vessels and increased cortisol and thyroxine only exacerbates inflammation and arterial plaque buildup.
Additionally, fatty acids released into the bloodstream by cortisol can lead to overproduction of low-density cholesterol (LDL).
High-density cholesterol, or HDL, actually helps keep the circulatory system functioning and has powerful healing value. But, notes Lee, the so-called bad version, LDL, contributes to dangerous plaque buildup on arterial walls that have been inflamed by toxins and high blood sugar — common byproducts of stress eating.
Upon detecting a threat, the hypothalamus signals the adrenal medulla (an autonomic-nervous-system node next to the adrenal glands) to secrete two hormones — adrenaline and noradrenaline — into the bloodstream. These increase heart rate and blood pressure. Blood is pumped to extremities and their muscles to help you run or go into battle, while gastrointestinal activity is reduced, producing the feeling of butterflies in the stomach. When this complex process is repeated routinely with no time for recuperation, you start to feel both lethargic and wound up — tired but wired.
Chronic stress also wears out the adrenal glands by overusing their store of energizing adrenaline. this can lead to “adrenal fatigue,” which can manifest as exhaustion, physical weakness, immune suppression, hormone imbalances, skin problems and depression.
Stomach and Intestines
The slowdown of the digestive process triggered by the sympathetic nervous system and the thyroid can prompt either overproduction or underproduction of digestive acids. Overproduction can lead to painful acid reflux (heartburn), while underproduction means your stomach has limited digestive power. Too little stomach acid can leave food in the system so long that it ferments rather than digests. This can produce bloating, create inflammation of the intestinal tissue and reduce the overall absorption of nutrients.
If your bowel’s inflamed you’re not getting nutrients out of the food you eat. You can eat really great food but still not benefit from it.
While some people do lose weight under stress, research reveals that high levels of cortisol can also encourage weight gain in two ways:
(1) Cortisol amps up the appetite for quick energy (namely, carbohydrates and sugar), triggering cravings and overeating.
(2) Cortisol also puts excess glucose in the bloodstream. When it’s not burned off through exercise (the equivalent of sprinting away from or fighting off the perceived attacker), it gets stored as fat in your body’s tissues.
That makes chronic stress a real enemy of overall fitness. You tend to gain weight because cortisol is making you want to eat more. But it’s also making you more likely to hold on to that food as fat, especially as abdominal fat.
Progesterone is a crucial hormone for fertility in women; it nourishes the lining of the uterus to support the implantation of an embryo and sustain a pregnancy. It’s also a key ingredient in the creation of cortisol in the adrenal glands. When the body demands large amounts of cortisol, its total amount of progesterone can diminish, leading to low libido and possible infertility.
The Aging Process
In 2004 a University of California, San Francisco research team reported that chronic stress may play a role in shortening telomeres, the tiny protein complexes at the ends of chromosomes that help protect genetic information as cells divide. As telomeres shorten, cells lose the ability to divide; they can also get confused about their mission and start to manifest serious ailments, from Parkinson’s to heart disease. (Other studies have linked shortened telomeres with the onset of dementia.) While cell loss is an integral part of the aging process, chronic stress accelerates it by munching away at these protective proteins so they diminish faster than they would naturally.