According to Selye, the ability of an organism to mount a resistance response to a stressor (AR)
and or maintain resistance to that stressor (SR) was dependent upon more availability of caloric
energy. He said there was a separate energy powering resistance that he called force adaptation
energy. Selye found adaptation energy diminished with exposure to adverse influences. When
adaptation energy ran low, an organism had difficulty resisting stressors, easily entered into SE,
and was liable to become diseased or even die. (1, 2) Indeed, Selye determined that the ability of
an animal to resist a stressor depended on the quantity of adaptation energy possessed by that
organism.
Concluding that adaptation energy was the power behind resistance, and that it was finite in
nature, Selye felt a better understanding of adaptation energy was crucial. (6) “Ever since 1937 I
have been intrigued by the fact that an already acquired adaptation to a certain stressor agent is gradually
lost in the course of chronic exposure. This means that the “adaptation energy” (or adaptability) of the
organism is a finite amount. There is a singular similarity between the manifestations of the exhaustion
stage, which ensues when adaptability is lost, and those of physiological senility. No doubt, inestimable
advantages would accrue to the practice of medicine if we succeeded in identifying “adaptation energy.” (6)
Selye encouraged the research community to probe adaptation energy, as it would increase the
medical community’s ability to keep people well.