by experiences and a unique genetic makeup, we’re all inherently different in how we respond to and deal with stress. At a Biology of Stress conference, Dr. Rachel Yehuda, a research psychologist at Mount Sinai School of Medicine, said, “We don’t walk into trauma the same way . . . and we don’t walk out of trauma the same way.”5 Yehuda is one of many scientists to show that reactions to stress can vary widely and that outcomes of stressful events arise from a complex interplay between genes and the environment.
Stress makes us all the more susceptible to illness and disease because the brain’s hypothalamus sends defense signals to the endocrine system, which then releases an array of hormones that not only get us ready for emergency situations but severely depress immunity as well. Even ordinary, day-to-day activities could push us over the edge, according to David Krantz, PhD of the Uniformed Services University of the Health Sciences, who found that blood flow to the heart is affected by what we’re doing and feeling each day and that serious problems can be avoided by keeping track of the simple daily stress in our lives.6 So just as in other physiological processes, the neuro-endocrine-immune system is at the very heart of the stress response—a series of chemical reactions that affect tissues and organs in ways that can wreak havoc on normal body functions.
It’s impossible to say exactly how many different negative reactions occur as a result of physical or emotional stress. What we do know, as indicated in Figure 2.2 below, is that the number is significant.
Figure 2.2: Physical Reactions During the Stress Response
In 1926, a young Hans Selye observed that hospital patients in the early stages of infectious diseases all exhibited similar symptoms, regardless of the type of disease they had. Later, while doing some physiology experiments, he noticed that three common responses occurred whenever any organism was injected with a toxic substance: (1) the adrenal glands enlarged; (2) the lymph nodes and other white-blood-cell producing organs initially swelled and then shrank; and (3) bleeding appeared in the stomach and intestines.
Selye called these three common responses the General Adaptation Syndrome and concluded that certain changes take place within the body during physical stress that disrupt homeostasis and trigger an array of diseases. No matter what type of organism he examined, from rats, dogs, pigs, and monkeys to humans, he found that chronic stress, if left untreated, induced a specific pattern that always led to infection, illness, disease, and eventually death (Figure 2.3). As shown in Hans Selye’s General Adaptation Syndrome, various stress reactions occur during each stage that make us more susceptible to disease.
Figure 2.3: Hans Selye’s General Adaptation Syndrome
Stage 1: Alarm Reaction: Any physical or mental trauma sets off an immediate set of reactions to combat the stress. Because the immune system is initially depressed, normal resistance levels are lowered, making us more susceptible to infection and disease. If the stress is not severe or long lasting, we bounce back and recover rapidly.
Stage 2: Resistance: Eventually, sometimes rather quickly, we adapt to stress, and there’s actually a tendency to become more resistant to illness and disease. Our immune system works overtime for us during this period, trying to keep up with the demands placed upon it. The danger here is that we become complacent and assume that we can resist the effects of stress indefinitely. Believing that we’re immune from the effects of stress, we typically fail to do anything about it.
Stage 3: Exhaustion: Because our body is not able to maintain homeostasis, we invariably develop a sudden drop in our resistance level. No one experiences exactly the same resistance and tolerance to stress, but at some point everyone’s immunity collapses and is followed by prolonged stress reactions. Life sustaining mechanisms slow down and sputter, organ systems begin to break down, and stress-fighting reserves finally succumb to what Selye called “diseases of adaptation.”
While I was a PhD student at Utah State University, my research showed a significant correlation between the emotional stress of oral exams and increased cholesterol and low-density lipoprotein (LDL) levels. Since then other researchers have corroborated my results, showing that total cholesterol and triglycerides can fluctuate by as much as 20 percent during stress and that the bigger the perceived stress the greater the fluctuation in blood lipid levels. LDL, the so-called “bad cholesterol,” is especially affected by stress.
The General Adaptation Syndrome is thought to be the main reason why stress is such a prevelant source of health problems. By changing the way our body normally functions, stress disrupts the natural balance—homeostasis—crucial for well-being. It can also subtract years from our lives by speeding up the aging process.
Resistance is the name of the game when it comes to disease. Stress is one of the most significant factors in lowering resistance and triggering the various mechanisms involved in the disease process. By learning the relaxation and stress management techniques found in later chapters, you’ll improve your overall health as well as your odds of living a more disease-free life.
Our ancient ancestors evolved what we know as the stress response as a survival mechanism to cope with events in their environment. Similar threats rarely exist in our modern world, thankfully. However, we still respond with the same fight-or-flight stress response—to situations we perceive as threatening but may or may not actually be—that, over a lifetime, create an internal environment primed for adverse stress reactions. The longer we allow those events to dominate our thoughts and reactions, the greater the chance they will eventually cause illness and disease.
These conditioned responses increase in strength because they become ingrained into our subconscious and are then triggered by mental or environmental cues. How we perceive events, and the ways in which we react to occurrences in our daily lives, will determine how our brain is conditioned and whether or not we create patterns that contribute more to health or to disease.
One of the more remarkable characteristics of the human brain is how easily it’s conditioned. We’ve all heard about Pavlov’s famous dog experiment. Every time Pavlov fed his dog, he would ring a bell. The dog began to associate the sound of the bell with being fed, and eventually, whenever Pavlov rang the bell, the dog would immediately begin salivating. The sound of the bell conditioned the dog’s brain to trigger the physiological response of salivating. Humans are no different in that we are just as easily conditioned to sounds, sights, smells, thoughts, and events.
Since the immune system is wired to the brain by a network of blood vessels, and the brain is the major organ of conditioning, immunity and the strength of the immune response depend on two things: (1) how we perceive stimuli and (2) what we do in order to condition ourselves to boost rather than to inhibit immune reactions. Negative perceptions evoke negative reactions, which depress the immune system. The more we evoke negative reactions, the greater the conditioning is and the more such reactions become a spontaneous response (see Figure 2.4).
Figure 2.4: Stress-Induced Conditioning and Habit-Formation
