Stress: Positives and Negatives
In answering the question "How does stress affect health?", we must first understand how a stressor interacts with our response to it. Picture stress as a battle between the stressor and the individual. What happens to the person after the battle depends on how strong the stressor was and how strongly the individual responded to it. Generally, when the stressor is not strong enough to topple the person, or when the individual emerges victorious, the stress produces positive results – increased self-worth, high self-esteem, and self-confidence to handle future stress. This kind of stress is called “eustress," wherein the gains far outweigh the losses. On the other hand, when the stressor is too strong to handle, the person may incur “injuries" that can lead to physical or psychological illness, and even death. This kind of stress is called “distress," wherein the losses significantly outweigh the gains.
Stress and the General Adaptation Syndrome
Humans and animals respond to stress in similar ways. During stress, they undergo a series of stages collectively known as the “general adaptation syndrome." The first stage, or the “alarm reaction stage," is the moment when the individual perceives the stressor and prepares against it.
The second stage, or the “resistance stage," is the period when the individual fights the stressor or runs away from it. The third and final stage, or the “exhaustion stage," is the time when the person’s coping resources (or strength) have depleted, and the individual goes into resting mode. If the stressor is eliminated before the battle reaches the third “round," the individual wins; but if the stressor persists when the individual is already weak, illness can follow.
The Biology of Stress: How Does Stress Affect Health?
By nature, the general adaptation syndrome is both innate and instinctual, which explains why it is observed across species. The fact that this stress response is involuntary complicates the process in which stress affects our health. This is the biology of stress. For instance, during the alarm reaction stage, our body undergoes drastic physical changes – dilated pupils, rapid heart rate and respiration, high blood pressure, increased blood sugar levels, profuse sweating, flushing, and braced/tensed muscles. These manifestations are due to the secretion of adrenal hormones, such as adrenaline, noradrenaline, and glucocorticoid/s (cortisol in humans).
These physical changes are useful when we really are in life-threatening situations and need to fight or escape. However, for most of us for most of the time the stressors we face are not life-threatening yet our bodies will still react as if in a red alert situation.
And these physical changes are more often destructive than helpful if we persist in being stressed out. The body continues to secrete adrenal hormones, resulting in a phenomenon called the “allostatic load." During allostasis, returning to homeostasis (the original balanced state of the body) becomes difficult, resulting in excessive amounts of cortisol in the bloodstream. Too much cortisol stunts physical growth in children, and can cause damage to brain cells, particularly in the hippocampus.
Stress affects our health not only through the secretion of adrenal hormones in the body. The general adaptation syndrome is also guilty of increasing our risk of contracting communicable diseases. This is because during stress, our involuntary response is to channel all our energy to fighting off or running away from the stressor. As a result, our immune system is suppressed (simply called “immunosuppression"), making us less able to defend ourselves against microbial invaders that we normally can resist. For example, common colds are quite prevalent in people who are under chronic stress (Cohen, Tyrell, & Smith, 1993).
Stress and Other Medical Disorders
Several other research studies have implicated stress in the development of bipolar disorder, anxiety disorders, depression, coronary heart disease, and some forms of cancer (Johnson & Miller, 1997; O'Shea, 2001; Selye, 1976a; Smith & Ruiz, 2002); but the underlying process is not yet clearly understood. Nonetheless, it is important to recognize that our knowledge of how stress affects health can shape the development of effective stress management programs and efficient methods for achieving a healthier lifestyle.
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