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Adaptation – it saves us, and it kills us

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We adapt to life from cradle to grave, and if our perspective is wide enough we can accurately say that illness, degeneration and dysfunction, are all adaptive responses to internal and external stressors.

So what are we adapting to?
….. to an ever changing combination of biochemical, biomechanical, and psychosocial stressors that are constantly exerting demands …… and we can usefully describe these individually by using the words such as ‘load’, or ‘pressure’ or ‘stress’.
How long a time, how heavy, how demanding, persistent or intermittent a stressor is, and how efficient the coping mechanisms are that have to handle the load, determines to a great extent the ultimate effect in terms of local or general health and functionality.
All this was beautifully described by Hans Selye in the 1940s and ’50’s (see photograph).
Imagine a tough piece of elastic, with all its qualities of pliability and strength…..and imagine what happens to the material and the functionality of the material after months or years of being stretched and twisted…..it adapts, and it eventually frays and, at a point in time, it snaps.
Selye described stages in which an initial defensive/protective (‘fight/flight’) alarm phase occurs in response to a stressor, followed, if the stressor (or multiple stressors) continues to be operative, by a phase of adaptation (‘resistance’) which, when exhausted, results in collapse, frank illness and death. Selye defined the basic, inborn, endogenous, self-regulating
process as homeostasis, which eventually failed when overloaded, at which time a stage of heterostasis was reached, where ‘something’ – treatment in this context – is required to restore health and the self-regulating (adaptive) potential.
Heterostasis calls for appropriate treatment to reduce adaptive load or to enhance adaptive capacity in order to avoid adaptation exhaustion, i.e. to avoid the point at which the ‘stretched elastic’ of the individual’s adaptive potential snaps. See the diagram at the start of this posting. It’s a bit small on screen but emphasises the stages of the GAS (and LAS): alarm – adaptation – exhaustion.
Selye used 2 basic terms to describe the processes that led to ‘adaptation exhaustion’ General Adaptation Syndrome (GAS), and Local Adaptation Syndrome (LAS)…..one involving the whole body and all its systems, and the other a local areas – say a shoulder – responding to adaptive demands placed on it – for example excessive serving while playing tennis.

In future blog postings I’ll expand on this theme in the hope that it will clarify some fundamental processes over which we have a great deal of control, in terms of how long we last, and how well we remain while we are here.

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