The association between vigorous exercise and certain aspects of mental health is well documented. Explanations for this relationship are not well understood, however, and recent developments in sport psychology suggest a renewed interest in health-related topics. Paradoxically, the more fundamental or prerequisite issue of exercise adherence has received little attention from a psychological perspective. Moreover, the research related to adherence has tended ro be atheoretical and unsystematic. The following discussion is designed to reinforce the significance of understanding influences on habitual exercise behavior and to characterize the nature of previous research in this area. An attempt is also made to provide some heuristic advantages which may facilitate future study of the exercise adherence question at both basic and applied levels.