Fitness technologies are a prominent example of the societal trend towards personal informatics. These technologies pair devices that have various embedded sensors with one or more apps to allow for the collection, analysis, socialization, and management of individuals' health and wellness data. We have limited insight into what drives the use of fitness technologies or how they may contribute to wellness outcomes. To address this gap, our study examines how exercise goals are related to fitness technology feature set use and how the use is associated with a measure of the exercisers' psychological well-being (ie, subjective vitality).We find that intrinsic exercise goals (eg, enjoyment or competence) are associated with the use of features that allow users to collect, analyse, and inform their exercise progress.Body-focused extrinsic exercise goals (eg, appearance) are also associated with the use of such features but are nega-