Stress wreaks havoc on the mind and the body. Many of us have also heard the expression stress kills. Stress is “a process in which environmental demands tax or exceed the adaptive capacity of an organism, resulting in physiological and biological changes that may place persons at risk for disease” (Contrada, 2011, p. 1). Once disease has taken hold, quality of life is impacted, and complications, including death, may result.
Although stressors can elicit different responses in different individuals depending on “conditioning” or their interactions with the environment, the body’s sympathetic nervous system and the hypothalamo-pituitary-adrenal (HPA) axis are typically activated during the stress response. This response, or “stress cascade,” allows the body to make the physiological and metabolic changes needed to cope with the demands of a homeostatic challenge (Goeders, 2003).
The hypothalamus, a portion of the brain that directs many vital functions in the body (such as the autonomic nervous system, endocrine function, homeostasis, motor function, and sleep-wake cycle regulation), responds to stress by producing corticotropin-releasing hormone (CRH). CRH binds to specific receptors on pituitary cells, which produce adrenocorticotropic hormone (ACTH). ACTH is then transported to the adrenal cortex (in the adrenal glands), stimulating the production of cortisol. Cortisol initiates a series of metabolic processes designed to reduce the harmful effects of stress through a negative feedback loop to both the hypothalamus and anterior pituitary. If the feedback is effective, the concentration of CRH and ACTH subside, resulting in a decrease in blood levels of cortisol and, ultimately, a return to homeostasis.
Short-term or minor stressors enable the body to respond in a mode that supports immediate survival. Short-term stress usually has a beginning and an end, and it can be beneficial to an individual. For example, if someone needs to quickly respond to a potential car accident on the highway, a short-term stress response can shut down non-essential body functions (such as digestion) and support essential body functions (like increased blood flow to the brain, allowing for improved reaction time). Once the stressor is removed, the body usually returns to normal, and there are few, if any, health effects (Contrada & Baum, 2011).
Long-term (chronic) stress occurs over an extended period of time (e.g., hours, days, weeks, months, or even years). The stress responses are prolonged, often leading to the development of illness, chronic disease, or death (National Cancer Institute, 2011; Seaward, 2012).