Allostatic load is “the wear and tear on the body” that accumulates as an individual is exposed to repeated or chronic stress. It represents the physiological consequences of chronic exposure to fluctuating or heightened neural or neuroendocrine response that results from repeated or chronic stress. The term was coined by McEwen and Stellar in 1993.
The regulatory model of allostasis claims that the brain’s primary role as an organ is the predictive regulation of internal sensations.Predictive regulation refers to the brain’s ability to anticipate needs and prepare to fulfill them before they arise. Therefore, in this model, the brain is responsible for efficient interoceptive regulation. Part of efficient regulation is the mitigation of uncertainty. Humans naturally do not like feeling as if surprise is inevitable. Because of this, we constantly strive to reduce the uncertainty of future outcomes, and allostasis helps us do this by anticipating needs and planning how to satisfy them ahead of time. But it takes a significant amount of the brain’s energy to do this, and if it fails to resolve the uncertainty, the situation may become chronic and result in the experience of “allostatic load”.The concept of allostatic load provides that “the neuroendocrine, cardiovascular, neuroenergetic, and emotional responses become persistently activated so that blood flow turbulences in the coronary and cerebral arteries, high blood pressure, atherogenesis, cognitive dysfunction and depressed mood accelerate disease progression.” In other words, all of the long-standing effects of continuously activated stress responses are referred to as allostatic load. And allostatic load can even result in permanently altered brain architecture and systemic pathophysiology. Further, as a result of these physical effects, allostatic load also minimizes an organism’s ability to cope with and reduce uncertainty in the future, which cements the entire cycle.