The adrenals sit above the kidneys and most of us have heard that these are responsible for the “fight or flight” reaction to stress. Briefly, there is a fast increase of the glucocorticoids, to enable the body to cope. It is the failure of this mechanism to work properly, in the presence of general stress, or the stress of disease, that they are concerned with in the use of replacement cortisone therapy. They call this condition Low Adrenal Reserve, or basically, Adrenal Insufficiency.