This article advances the claim that a new ‘fitness boom’ has arrived, one marked by the proliferation of devices such as wearable fitness trackers. The first fitness boom of the 1970s/1980s was characterized by the heightened availability of fitness ‘tools’ and the supposition that pursuing a ‘fit’ lifestyle was tantamount to responsible living. The new era in fitness intensifies foregoing fitness trends, rather than departing from them completely. Specifically, the second fitness boom is deemed to be characterized by the following traits: (1) the manifestation of socio-technical networks, (2) an emphasis on human–technology interactivity, (3) data-intensiveness, (4) customization in the interest of ‘optimization’, (5) the option for individual users to partake in wider online communities and, finally, (6) both ‘new’ and ‘old’ forms of commodification. With these characteristics in mind, a case is made that fitness is a site for prosumption – production and consumption together – now more so than ever. More importantly, fitness is a site for automated prosumption in that fitness data can be generated with limited effort from fitness participants. Consideration is given to the significance of automated prosumption in the fitness realm as it pertains to fitness and to the notion of prosumption both.