Stress…even the word itself connotes negative feelings, doesn’t it?
While we could spend time discussing specific elements of stress, no one really needs an introduction to this familiar, but unwelcome, intruder. Studies show that Americans progressively tend to shoulder more and more stress from a variety of sources, and most of us have developed an overly busy lifestyle.
If we’re honest with ourselves, most of us would reluctantly concede that stress is always present (though the intensity may vary from week to week). While mountains of medical evidence show that chronic stress has long term negative effects on the body, we don’t really need external proof of that fact because we know it intuitively.
Stress takes a toll on our health and often the price is too high.
At the same time, there is confusion about how stress manifests itself within the body and what the health risks are, beyond tightened back muscles, tension headaches, and sleepless nights from increased anxiety. Unfortunately, there are also conflicting messages about how best to cope with stress and avoid its debilitating effects.
In a short series of blog posts we will discuss some of the physiologic effects of stress and some effective ways that we can address them from a natural perspective. This will include both non-pharmacological strategies, as well as discussion about the different classes of OTC vitamins and supplements.
Obviously, the body’s mechanisms for managing stress are very complex and not fully understood, even in the context of modern medicine. In fact, the endocrine system of the body involves some of the most complex subject matter in medicine as a whole. To effectively discuss healthy interventions we can make, we must first introduce some terminology and discuss some basic physiology. That is the intent of this first article – to provide some basic education about our body’s response to stressors. Although this particular information is somewhat technical for a blog, please hang in there with us. It forms the foundation of our future discussion on mitigating the effects of stress.
Let’s dive in!
Most people are familiar with the phrase “fight-or-flight response” and have a basic idea of what it means. This physiologic reaction of our bodies is simply amazing, and is intended to increase our chance of survival in the face of immediate danger. The heart speeds up, blood vessels dilate to deliver an increased volume of blood filled with oxygen and nutrients to the muscles used for escape. Additionally, blood is redirected away from secondary functions not necessary for escape, such as digestion. The body makes more glucose available, providing the fuel the muscles and brain need to confront the perceived obstacle. In an otherwise healthy life, this stress response is only intended to be activated occasionally, to confront episodic threats.
With substantial time between crisis events, our bodies were designed to relax the fight-or-flight response allowing the body to manage other functions well, such as digestion, immunity, healing, and psychological wellness. Ironically, the system meant to increase chance of survival, when chronically activated, can significantly damage our health.
Here is the crux of our problem, demands and lifestyle choices create a habitual pattern that keeps our stress response on high alert all the time, with too little recovery interval, ultimately depleting the resources our body desperately needs to continue mounting a healthy response to stress. Progressively, this negative spiral affects virtually every major physiologic system in the body.
Our body’s adaptive response to stress is managed by a complex system known as the HPA axis, more specifically, the hypothalamic-pituitary-adrenal axis. This axis is a complex series of glands that communicate with each other through chemical mediators called hormones to generate a physical response (figure 1 below). The HPA axis is an absolutely indispensable part of our existence.
When the emotional-interpreter section of the brain recognizes a stressor, the body begins subconsciously preparing for an energetic response. It is interesting to note that the body is programmed to respond to all kinds of stress, physical, emotional, psychological, environmental, and even perceived stress.
The hypothalamus in the brain, one of the primary communicators with the rest of the body, releases a hormone called corticotropin-releasing factor (CRF). CRF goes to the pituitary gland, also located in the brain. In response to CRF, the pituitary gland releases a different hormone into the blood, adrenocorticotropic hormone (ACTH), which stimulates the adrenal glands, also known as the adrenal cortex, sitting on top of the kidneys. Among other chemicals, the adrenal glands release cortisol, norepinephrine, and epinephrine, commonly known as adrenaline.1
Epinephrine makes the heart rate increase, which increases blood pressure through the body so more oxygen and nutrients can reach the muscles. It also increases our respiration rate and opens our airways to take in higher volumes of oxygen. The brain becomes hyper-aware of surroundings and focuses in on the senses. It triggers other organs such as the liver to release more glucose (blood sugar) into the blood to feed the muscles. The body is primed and ready to meet the threat, often before we can consciously identify the threat’s full nature.
Cortisol is another essential hormone released by the adrenal glands. It is a member of the steroid family. One of its primary functions is to increase blood sugar and energy for the muscles, helping epinephrine do its job. It also assists in reducing the function of secondary body systems that are non-essential for immediate survival, such as digestive function, immune function, and sexual function.
A key point in a healthy HPA axis, as seen in figure 1, is that high cortisol results in a feedback loop that tells the hypothalamus to stop producing CRF because there is enough cortisol in the body. This feedback is critical for turning off the fight or flight response once the threat has passed, and allowing normal, balanced system functions to resume. This healthy state of balance is referred to as homeostasis. In an ideal world, we would live the majority of our lives in healthy homeostasis with only the rare full scale stress response.
Reality in our over achieving western culture generally tells a different tale.
Long term exposure to continuous stress often creates imbalance in the HPA axis and causes it to stop functioning properly. As a result, individuals can experience either over-active or under-active adrenal function. Our metabolic reserves become exhausted and our ability to effectively cope with stressors is gradually degraded. Left unchecked, this decline can result in serious and long term medical consequences.
For example, sustained high heart rate and high blood pressure from enduring chronic stress response leads to increased risk of heart disease and enlargement of the heart muscle. Additionally, continuously elevated blood glucose levels increase the risk for both weight gain and diabetes. The immune system becomes suppressed, making it easier to contract bacterial and viral infections. Individuals exposed to chronic stress have higher rates of digestive dysfunction, immune dysfunction, and sexual dysfunction. 3
This unhealthy cycle is described by a term called “allostatic load” which refers to the consequences of chronic stress on the body.
The top graph in Figure 2 (above) shows the normal response to stress: cortisol rises, but the body manages the stress through increased energy in the body for a period of time and then returns to baseline. This is a healthy response. Exposure to chronic stress over time can alter this response negatively.
In the lower panel, the top left graph shows the body responding to stressors more frequently, but mounting a healthy response then returning to baseline. The middle right graph shows more frequent stressors, but instead of making a correct response, the ability of the body to respond degenerates over time. The bottom left graph shows a scenario when the body cannot return to baseline and the response is constant. Eventually, chronic stress exposure seriously inhibits the ability of the HPA axis to respond. When this happens, even the smallest stressor is exaggerated and becomes too much for the body to manage. This can lead to chronic fatigue and many other challenges. The body is too exhausted to handle the negative effects of stress. 4
All of this paints a somewhat bleak picture of the consequences of unmitigated chronic stress. In reality, once they become evident, many of the serious consequences are life-long. The good news is that we are blessed with the capacity of choice. We can take some proactive steps to address the allostatic load our bodies are bearing, however significant it may be.
These lifestyle choices include exercise, building time margins into overloaded lives, forging healthier relationships, developing healthy sleep habits, and nutritional support through dietary changes. We can also make some positive interventions through the use of natural supplements and vitamins that support a healthy HPA axis and rebuild essential metabolic reserves.
We hope this technical blog has been helpful in providing a very basic understanding of our body’s stress response mechanisms. Please stay tuned to Sona Pharmacy’s blog and join us next month for Part 2 in our blog series, “The High Cost of Stress”?
Scott Henson, Pharmacist and Guest Blogger – Ashley H. McKnight, UNC PharmD Candidate, Class of 2018
References:
- Alschuler L, ND. The HPA Axis. http://www.integrativepro.com/Resources/Integrative-Blog/2016/The-HPA-Axis. Published October 31, 2016. Accessed May 13, 2016
- Understanding the Stress Response. Harvard Health Publications. Harvard Medical School. http://www.health.harvard.edu/staying-healthy/understanding-the-stress-response. Published March 2011. Updated March 18, 2016. Accessed May 13, 2017.
- Randall, M. The Physiology of Stress: Cortisol and the Hypothalamic-Pituitary-Adrenal Axis Dartmouth Undergraduate Journal of Science http://dujs.dartmouth.edu/2011/02/the-physiology-of-stress-cortisol-and-the-hypothalamic-pituitary-adrenal-axis/#.WRfX-VMrJE4. Published Fall, 2010. Updated February 3, 2011.
- McEwen BS. Protective and damaging effects of stress mediators. New Engl J Med 338(3):171–179. 1998. https://ehp.niehs.nih.gov/119-a430/. Published October 1, 2011
