Allostatic Load
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The concept of allostasis was first posited in 1988, by biologist Joseph Eyer and anatomist, physiologist, and neuroscientist Peter Sterling, to describe a multifaceted process through which the body can achieve homeostasis despite changing conditions and environmental stresses.
In practice, this might mean that a student is anxious about an important test, and the anxiety and stress associated with that impending exam sends shockwaves of chemicals through their body, making them jittery, distracted, unhappy, and maybe even sick.
But with time, this allostatic system shifts the student’s internal processes toward balance, toward a less-stressed-out resting point, through the recalibration of that person’s many hypothalamic–pituitary–adrenal, or HPA axis-related components: her energy expenditure, her digestion, her mood chemicals, and the like.
This concept can apply equally to stubbing one’s toe, or the stresses and injuries associated with escaping a war-zone or an attempted murder. Returning one’s physical and neurological functions to something approximating normal—normal for the person in question—is the whole point of this system of systems, regardless of the type or potency of the factors that are pulling one away from that relatively balanced resting state.
This is similar to the biological concept of homeostasis, which refers to the optimal functioning of an organism’s systems in terms of temperature, pressure, fluid balance, the concentrations of various substances, blood-sugar levels, and so on.
Allostasis and homeostasis overlap in many regards, and some skeptics have claimed that the former is just the latter with different terminology.
But in general, homeostasis seems to be more fundamental, and focused on our bodily tendency to always be nudging us toward what’s called our homeostatic range: the blood pressure, chemical composition, energy usage, and so on, that keeps us in peak, balanced, operational shape.
Allostasis, on the other hand, is more focused on the flurry of internal activity that pushes back against the psychological and physiological consequences of stressors.
So if some kind of injury or psychological strain pushes us beyond our homeostatic range, our allostatic systems kick into gear, tweaking our mood, emotions, immune system functions, energy usage, sexual processes, and other glandular and hormonal functions, to try to pull us back toward something less taxing, more balanced, and more sustainable.
Key to understanding allostasis is recognizing that our allostatic systems can be stressed and strained over time by consistent or overwhelming allostatic loads.
Chronic stress or chronic pain, for instance, can result in wear-and-tear damage to the systems that are generally used to nudge us back to equilibrium. As a result, if we experience significant or long-lasting pain or stress, our ability to cope with pain and stress can be lessened: the processes that would generally be used to help us cope are weakened by the ever-present or more potent than usual, onslaught.
This can occur even as a result of what many of us would consider to be very small, easily handled issues.
A $50 phone bill may not seem like a notable stressor to some of us, but to someone who’s finances are already strained, that $50 bill can become the psychological equivalent of a toothache that won’t go away. With time, that seemingly small concern can cascade into a much larger one, causing other issues to seem more overwhelming than they are, reducing one’s immune system function and energy usage efficiency, and leading to more pain, more stress, more conflict, and less capacity to deal with any of these increasingly migraine-scale headaches.
One important takeaway from this concept is that our internal processes are influenced by even seemingly small issues that we often, at first glance, consider ourselves to be more that capable of dealing with, consequence-free.
This extends beyond our own internal processes, too, to everyone we encounter every day. The version of a person we encounter on the street or at work or in the check-out line may not be representative of who that person is under other circumstances, with different sets of stressors and pains at play, and during periods in which they’ve had relatively more or less time to repair their allostatic systems after a period of intense coping and rebalancing.
It’s also worth knowing that this system can be intentionally reinforced, generally by changing the environmental and psychological circumstances in which we spend most of our time.
That might mean changing our workout routines or diets to ensure we’re overall physiologically healthier and more resilient, it may mean adopting a meditation practice or in some other way tweaking our perception of self, of the problems we face, and of our capacity to face those problems.
It might also mean changing the work we do or the place we live, to reduce consistent, chronic stressors and environmental harms, like the people we surround ourselves with, or the amount of pollution in the air, or the local noise levels that may keep us up at night or reduce our ability to focus during the day.
None of these adjustments are terribly easy to implement, as most require the wholesale recalibration of our lifestyle circumstances, rather than just the taking of a pill, or the introduction or subtraction of certain habits.
But research has shown that our allostatic systems can be reliably reinforced and renewed by such changes.
So it’s worth considering what adjustments we might make to our foundational circumstances, based on the positive impact such changes can have on the quality and resiliency of our underlying physical and neurological functions.
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