What makes chronic stress potentially lethal is its duration and the constant accumulation of its effects. Stress upon stress grows like compound interest on a loan. When only the minimum payment is made, the balance continues to grow and can never be fully repaid.
Humans respond to stressors such as physical or perceived danger, an infection, or a crowded and noisy environment, by initiating a complex biopsychosocial adaptation and coping response. This response is initiated by the sympathetic nervous system and leads to release of excitatory stress hormones (the catecholamines) and glucocorticoids from the adrenal cortex (the well-known adrenaline rush).
The objective is to engage with the situation, resolve it and return to the status quo. This process of regaining stability through change and adaptation is called allostasis. The arousal and mobilization of biopsychic resources is intended to be temporary and is shut off when the challenge has passed.
Work, interpersonal, and environmental interactions created by daily living ensure that there is never a shortage of challenging situations that trigger this response. The popular saying, "when it rains it pours," refers to the not uncommon challenge of having to cope with more than one such situation at once or within a very short time. Most individuals can cope with the life’s demands and are able to regain allostasis.
Some individuals are not able to cope, and this inability creates a condition of allostatic load. In this scenario, there is never a return to the status quo or a regaining of stability. In fact, the arousal and mobilization of biopsychic resources at high levels becomes the new normal. Over weeks, months, or even years, exposure to elevated levels of stress hormones can produce chronically high allostatic load and overload, types 1 and 2, with predictably serious health consequences.
Type 1 Allostatic Load
If the biopsychic energy required to meet the demands created by one’s cumulative allostatic load routinely exceeds the energy intake and what can be mobilized from one’s own resources, type 1 allostatic overload occurs.
Allostatic overload type 1 is characterized by a significant increases in the circulation of glucocorticoids in the bloodstream (and other hormonal mediators of allostasis) that trigger physiological and behavioral changes which refocus the individual from functioning at normal levels of stress in daily routines into a high-stress high-alert survival mode.
Type 2 Allostatic Load
If energy demands are not exceeded and the individual continues to take in or store as much or even more energy than he/she needs—perhaps as a result of stress-related food consumption, choice of a fat-rich diet, or metabolic imbalances (prediabetic state) that favor fat accumulation—then type 2 allostatic overload occurs.
Allostatic overload type 2 is marked by lesser but higher than normal levels of glucocorticoids (and other hormonal mediators of allostasis) that do not trigger physiological and behavioral responses, in such a way the individual remains stuck in a situation of high allostatic load without resolution.
Allostatic Load and Its Consequences
Elderly people who had a lifetime of sustained economic hardship can have a more rapid decline of physical and mental functioning.
Hypertension is often an indicator of job stress, particularly in factory workers, in other workers with repetitive jobs and time pressures, and in workers whose jobs were unstable due to financial and market conditions.
In certain societies, conflict and social instability have been found to increase illness and mortality. For example, cardiovascular disease is a major contributor to the almost 40% increase in the death rate among Russian males in the social upheaval following the fall of Communism. High blood pressure causes atherosclerosis as well as increased risk for heart attacks.
Abdominal obesity is another stress-linked change, which is often a precursor to more serious illness such as diabetes. The immune system is also a likely target of psychosocial stress, increasing vulnerability to the common cold and other more serious infections.