I’m sure you’ve felt stress run through your body before. Maybe you felt your heart beating out of your chest and pounding against your body as everything seemed to speed up beyond control, or maybe you were unable to even fall asleep as your brain was overwhelmed. Or, maybe you’ve just felt slightly irritated at one specific, nagging problem. Well, as you probably know, these are all forms of stress. Stress seems to dominate and slowly take over our lives--especially as we get busier and busier--yet many don’t have a solid understanding of stress and are thus unable to adequately address it. So, what is this intense feeling and source of tension, exactly? What is stress?
The Stress REsponse
Generally speaking, stress is the result of the body’s non-specific response to any perceived threatening stimuli, dubbed the General Adaptation Syndrome (GAS) or the “fight-or-flight response.” Our bodies initially developed these responses as survival mechanisms to be better suited to either run away or confront and end a threatening stimulus. While waiting for a test to begin may seem much less threatening than making eye contact with a wild bear, both situations invoke physiological changes to optimize the bodies’ response as we perceive both situations as threatening--albeit in vastly different ways.
General Adaptation Syndrome
Hans Selye determined that the body’s response to any form of “threatening” stimulus, whether physical or psychological, elicits the same response of stress in the General Adaptation Syndrome (GAS), which is comprised of three key phases: alarm, resistance, and exhaustion. In the initial alarm phase, the body first recognizes the threatening stimulus and the resisting response to the stressor is actually briefly decreased. However, it quickly rises back up as the body begins to expend its resources for the resistance stage; in the resistance stage, the stress response is propelled as the body uses its resources and adjusts its biological processes to be set in the fight-or-flight response. Finally, if the stimulus persists for a long duration and elicits chronic stress, the body transitions to an unhealthy exhaustion state. Some believe that this is due to the body’s full expenditure and depletion of resources that otherwise drive the stress response, while others believe that this is the body’s purposeful shutdown of the stress/resistance response in order to prevent further long-term damage (Weiten, 2002). In both scenarios, if chronic stress precipitates to the point of exhaustion, the body’s resources are ‘exhausted’ and there is a dangerously increased level of susceptibility to disease or illness and long-term physical health detriments.
Specific Physiological Response and HPA-axis
When encountering such stressful or threatening situations, our sensory organs like our eyes and ears notify our brain of the dangerous stimuli through sensory nerves. This information is sent to the amygdala, the portion of our brain that deals with emotion and emotional responses, which then notifies the hypothalamus--the part of our brain that coordinates some of the body’s homeostatic (regulatory) mechanisms. There, the hypothalamus organizes the response and sends the information through the autonomic nervous system or through the nervous system dealing with involuntary processes. Of the autonomic system, it activates the sympathetic nervous system, the system that’s responsible for the fight-or-flight response as it increases the rate of certain bodily processes to be optimized for addressing threatening situations. As a result, adrenal medulla release adrenaline and norepinephrine (catecholamines) into the bloodstream which increase heart rate and breathing rate to allow for more oxygen and glucose to flow throughout the body for heightened senses and an improved capacity for physical activity.
After the initial response, the HPA axis is activated--a second system comprising the hypothalamus, pituitary gland, and adrenal cortex. Essentially, the HPA ensures that the body continues to be in the fight-or-flight state while stressful stimuli is still present. The hypothalamus now releases corticotropin-releasing hormones (CRH), which causes the pituitary gland to release adrenocorticotropic hormones (ACTH). This hormone then causes the adrenal cortex to release cortisol which maintains the fight-or-flight response, reducing swelling and increasing energy access throughout the body. When the ‘threat’ subsides, cortisol levels fall and the body returns to a resting state.
Effects Stress has on the Body
When there is continuous stress, the HPA axis stays activated which is detrimental to our long-term health: “Persistent epinephrine surges can damage blood vessels and arteries, increasing blood pressure and raising risk of heart attacks or strokes,” and “Elevated cortisol levels … inadvertently contribute to the buildup of fat tissue and to weight gain” by increasing appetite which results in increased storage of fat. (Harvard Health). Chronic stress levels can also disturb your circadian rhythms, disrupting your sleep-wake cycle and resulting in moodiness, memory loss, brain fog, as well as other health detriments. Roberta Lee, MD, also says that persistent stress “[sets] the stage for cardiac arrest,” because “high blood pressure from constricted vessels and increased cortisol … only exacerbates inflammation and arterial plaque buildup,” and because “fatty acids released into the bloodstream by cortisol can lead to overproduction of low-density cholesterol (LDL).” As the blood vessels become less elastic and more resistant from increased constriction (to pump more blood throughout the body in times of stress), the risk for blood clots and many other dangerous diseases significantly increases. When stressed, the body’s appetite is increased due to the increased energy demand, and combined with increased LDL levels, such stress eating can contribute to more, “dangerous plaque buildup on arterial walls.” (Spayde).
Countering Stress
So, how can the negative effects of chronic stress be mitigated--or how can stress levels itself be reduced? Dr. Herbert Benson found that by triggering the relaxation response, blood pressure can be reduced over time. Through “deep abdominal breathing, focus on a soothing word (such as peace or calm), visualization of tranquil scenes, repetitive prayer, yoga, and tai chi,” more than half of his test subjects had reduced their systolic blood pressure, and 50% of those people were able to “eliminate at least one [of their] blood pressure medication” with continued relaxation exercises--a proportion significantly higher than the control group that didn’t perform such exercises (Harvard Health). Physical activity works to reduce stress as it allows for deep breathing and mental focus, and it decreases muscle tension.
The Buffering Theory suggests that the presence of some sort of social support acts as a buffer from the negative effects of stress. The reason for this theory is unclear, but it’s been proven that “people who enjoy close relationships with family and friends receive emotional support that indirectly helps to sustain them at times of chronic stress and crisis,” reducing overall levels of stress that would otherwise harm those individuals (Harvard Health).
Works Cited
Harvard Health Publishing. “Understanding the Stress Response - Harvard Health.” Harvard Health, Harvard Health, 6 July 2020, www.health.harvard.edu/staying-healthy/understanding-the-stress-response. Accessed 23 Jan. 2021.
Spayde, Jon. “The Science of Stress.” Experience Life, 21 May 2019, experiencelife.com/article/the-science-of-stress/. Accessed 23 Jan. 2021.
Weiten, W. (2017). Psychology: Themes and variations.
Comments