Clinical Dose-Response Effects of Exercise

Abstract

Stimuli used to probe the acute physical/physiological response to exercise are well known and characterised so that the pattern and size of their effect may be used diagnostically with some precision (21,22). There is no similar precision of thought on training. Although most training studies show the generally positive benefit of exercise, there is no formal training theory developed for exercise such as the type, quantity or pattern of a training stimulus necessary to produce a prescribed measured effect and the field remains empirical and fallible. Conflicting data on physical, physiological and biochemical measures may be widely observed in studies of the effect of a reduced, maintained, increased or terminated stimulus in a subject undertaking training (4,5,9-12,14). In clinical studies definition of a threshold level of training for reducing such symptoms as sedentary afflictions (8,16), high plasma cholesterol (18) or moderate to medium hypertension (6,20) is still qualitative, expressed variously, in units of distance covered, time spent, or intensity of effort in training and a complex periodisation system specifying the allocation of training time to various levels of activity and relative rest/detraining. Without a theory of training, such empirical investigations remain imprecise and their conclusions speculative and argumentative. A unique feature of the new theory is the proposal of an appropriate quantitative, unit measure of training which must be defined and adopted so that quantitative study of the training response to a stimulus may be unambiguously conducted. The idea will be developed and rationalised further in this paper.