Research has shown repeatedly that the "feeling better" effect of exercise is far more moderate than generally claimed. Examinations of subgroups in secondary analyses also indicate that numerous further variables influence this relationship. One reason for inconsistencies in this research field is the lack of adequate theoretical analyses. Well-being output variables frequently possess no construct definition, and little attention is paid to moderating and mediating variables. This article integrates the main models in an overview and analyzes how secondary analyses define well-being and which areas of the construct they focus on. It then applies a moderator and/or mediator framework to examine which person and environmental variables can be found in the existing explanatory approaches in sport science and how they specify the influence of these moderating and mediating variables. Results show that the broad understanding of well-being in many secondary analyses makes findings difficult to interpret. Moreover, physiological explanatory approaches focus more on affective changes in well-being, whereas psychological approaches also include cognitive changes. The approaches focus mostly on either physical or psychological person variables and rarely combine the two, as in, for example, the dual-mode model. Whereas environmental variables specifying the treatment more closely (e.g., its intensity) are comparatively frequent, only the social support model formulates variables such as the framework in which exercise is presented. The majority of explanatory approaches use simple moderator and/or mediator models such as the basic mediated (e.g., distraction hypothesis) or multiple mediated (e.g., monoamine hypotheses) model. The discussion draws conclusions for future research.Keywords Well-being . Exercise . Mediation . Moderation . Explanatory approaches Everyday assumptions about the effects of exercise on wellbeing are unanimously positive-as numerous popular science books confirm with promising titles such as The aerobics programs for total well-being [1] or Life skills: 225 ready-to-use health activities for success and well-being [2]. Even in the early years of scientific research in this field, few would have disagreed with the statement that "the 'feeling better' sensation that accompanies regular physical activity is so obvious that it is one of the few universally accepted benefits of exercise" ([3], p. 306). Nonetheless, a host of primary studies carried out between 1960 and the mid-1990s delivered no unequivocal confirmation of this hypothesis. As a result, studies since the 1990s have increasingly been integrated and compared in both narrative (e.g., [4,5]) and meta-analytic reviews (e.g., [6,7]).In contrast to popular science claims, quantitative secondary analyses reveal that the overall effects on (subjective) well-being (SWB) 1 are not only small but also show a great deal of variation. For example, McAuley and Rudolph ([8], p. 68) have written: "Although many studies extol the almost intui...