A basic characteristic of life is the dynamic equilibrium between conflicting forces in complex systems, while economy and remarkable attention to detail is maintained. This dynamic equilibrium, which is universally named “homeostasis” is contributing to the existence of life through the coordination of multiple homeostatic and regulating mechanisms defending against numerous disruptors.
What is stress?
Many attempts have been made to precisely define the term “stress”. The most recent attempt describes stress as a situation of threat or presumed threat towards homeostasis, which can be restored using a complex system of behaviors and normal adaptive reactions of the organism. The pioneer researcher in the field of physiology Dr Hans Seyle mentions that: “everybody knows what stress is, but no one actually knows”. We can see this paradox described by Seyle in our daily life. The inclusion of a “perceived’ threat in the updated definition of stress is showing the subjectiveness of perceiving danger in a bio-psycho-social level. The ambiguity regarding “stress” is reflected on the fact that quite often stress is confused with symptoms of anxiety disorders, with somatic symptoms that cannot be interpreted in another way. In addition, stress can be defined in the bibliography as “dyshomeostasis” or “kakostasis”. But is every “threat” a fatal or harmful situation?
What is the System of Stress?
Any internal or external change can be perceived as potentially threatening for the existing equilibrium of the organism. The organisms that have succeeded in developing mechanisms of managing this challenge in a way that benefited their survival and evolution, acquired resilience and biological intelligence. Those organisms transfer this skill to other organisms as an organized system of “crisis management”, which is called the System of Stress.
The basic conditions for activating the System of Stress are the following: the presence, the recognition, the evaluation and the influence of a stress causing factor. This factor may be external or internal, physiological or psychological, acute or chronic. The first step of this reaction and adaptation is receiving a stimulus from the brain which is assessed as potentially threatening or not. The central/cerebral part of the System of Stress includes the hypothalamus, a part of the diencephalon which is responsible for regulating vital functions of the organism and the locus caeruleus (LC/NE) in the area of the pons. In this area the adrenocortical/sympathetic system is situated, from which the “fight or flight” response originates. The peripheral part of the System of Stress consists of: the axis of hypothalamus- pituitary-adrenal glands, the peripheral part of the sympathetic system and finally the stress hormones: cortisol and catecholamines (adrenaline and noradrenaline). Cortisol is one of the main stress hormones. It activates metabolic pathways and makes the necessary modifications in order to ensure the right response to the stressful conditions, while simultaneously it has the capacity to suppress the same stress system that initially led to the cortisol secretion. Adrenaline and noradrenaline are the first hormones to act by getting the whole organism in a state of alert, modifying the necessary somatic functions e.g. increasing the heart rate, optimizing the pulmonary function, and simultaneously reducing the non-necessary functions like digestion. Finally, the Stress System is in a continuous communication with numerous other functions and networks including the decision making and cognitive centers, the limbic and dopaminergic system of fear/anger and reward, cerebral centers of alertness and rest, growth of the organism, the reproductive system, the thyroid hormones, the digestive system, the cardiopulmonary system and the metabolic system.
The change from a known condition, through a transitional period, towards a new equilibrium is a process that requires a lot of effort. In various milestones of human development and also in the development of other species, an external stressful factor like lack of nutrition, a natural disaster, a pandemic, led the organisms that managed to survive to establishing a new equilibrium and accessing new paths that were previously unattainable. From walking on two legs and the wandering tribes up to creating communities and towns, the human race has achieved the optimum adaptation for its survival and evolution, aided by a number of internal and external factors. In this way man has finally proven that adaptability is probably the greatest intelligence of an organism.
Everything is a matter of equilibrium, but not always the same one
In a similar way, the System of Stress as a gift of evolution to organisms is recruited in order to restore the organism to a state of homeostasis which may be similar to the previous one or it may be defective due to inadequacy or over function of the adaptive mechanisms. It may also not only restore the organism to the previous level of healthy homeostasis, but it may bring new beneficial modifications that can finally lead to an improved homeostasis. This state is called “hyper-homeostasis” or “hyperstasis”. Given the above, an acute stress may be beneficial to the organism. A common example is the beneficial impact of moderate intensity exercise to the organisms’ immunity, while a stressful condition of high intensity or long duration may be the precursor of a pathological state, when its management is not successful. Chronic stress e.g. chronic disruption of the circadian biorhythm, obesity as a state of chronic inflammation, chronic disease, substance abuse, living in an abusive environment, chronic exposure to harmful substances or conditions, is directly implicated in a multitude of non-contagious diseases like cardiovascular disease, diabetes mellitus, cancer and other non-contagious diseases, which are directly linked to the System of Stress and cause 90% of deaths in Europe according to WHO. Those are the pandemic of modern times and the majority of them are preventable.
Stress as a necessary ingredient of life
Experiences from all over the world show that life cannot exist without the continual loss and finding of a new balance, in a perpetual dance of heterogeneity and communication. The international mobilization for recognizing the importance of how stress is managed, reveals the necessity of acquiring a different, constructive and mutual relationship with conflict, without regarding it as a destruction. Failing to grab the opportunity that accompanies any challenge leads sooner or later to disease and makes the organism exponentially susceptible to illness.
Any difficulty that arises in any given day, in our whole life can be a Teacher as long as we are receptive, observant and courageous to listen to what it has to say to us. A common serious false belief is that something beneficial is always pleasant. Something beneficial is not always pleasant and something pleasant is not always beneficial. It is the great challenge of a lifetime to achieve the ability to discriminate between those two and honor them as we are worthy of this as humans. This may be a difficult process, but it is also an even more interesting one.
Written by Christina Kounatiadou,
doctor training in Psychiatry
- Chrousos, George P. “Stress and Disorders of the Stress System.” Nature Reviews Endocrinology, vol. 5, no. 7, 2 June 2009, pp. 374–381, www.nature.com/articles/nrendo.2009.106, 10.1038/nrendo.
- Nicolaides, Nicolas C., et al. “Stress, the Stress System and the Role of Glucocorticoids.” Neuroimmunomodulation, vol. 22, no. 1-2, 2015, pp. 6–19, 10.1159/000362736.
- Godoy, Lívea Dornela, et al. “A Comprehensive Overview on Stress Neurobiology: Basic Concepts and Clinical Implications.” Frontiers in Behavioral Neuroscience, vol. 12, no. 127, 3 July 2018, www.ncbi.nlm.nih.gov/pmc/articles/PMC6043787/, 10.3389/fnbeh.2018.00127.
- Tsigos, Constantine, and George P Chrousos. “Hypothalamic–Pituitary–Adrenal Axis, Neuroendocrine Factors and Stress.” Journal of Psychosomatic Research, vol. 53, no. 4, Oct. 2002, pp. 865–871, 10.1016/s0022-3999(02)00429-4.009.106.
- Benarroch, Eduardo E. “Physiology and Pathophysiology of the Autonomic Nervous System.” CONTINUUM: Lifelong Learning in Neurology, vol. 26, no. 1, Feb. 2020, pp. 12–24, 10.1212/con.0000000000000817. Accessed 27 May 2021.
- Chrousos, G. P., and P. W. Gold. “The Concepts of Stress and Stress System Disorders. Overview of Physical and Behavioral Homeostasis.” JAMA, vol. 267, no. 9, 4 Mar. 1992, pp. 1244–1252, pubmed.ncbi.nlm.nih.gov/1538563/.