To increase physical activity in sedentary individuals, interventions and theoretical frameworks have, for a long time, focused on goal setting, feedback, and behavioral monitoring. Regardless of these efforts and good intentions, the WHO still describes the world as suffering from a pandemic of physical inactivity. Studies from the last decade provided evidence that automatic processes regulating exercise behavior may in part explain this paradox. The theory of effort minimization in physical activity (TEMPA) postulates that humans evolved an adaptive mechanism that favors behaviors minimizing energetic cost. This mechanism would make physical inactivity attractive, rewarding, and costly to avoid. However, these processes have only been investigated with behavioral outcomes (i.e., reaction times) or electroencephalography (EEG), that lacks the spatial resolution to identify specific neural circuits. Here, we used an approach-avoidance task (AAT) with basic stimuli of physical activity, inactivity, and a control condition, paired with functional magnetic resonance imaging (fMRI). Behavioral results showed more errors when avoiding physical inactivity compared to the other conditions and failed to replicate previous findings that displayed an approach bias towards physical activity. fMRI data analysis indicated a significant increase in the Blood-Oxygen-Level-Dependant (BOLD) signal in primary and secondary visual areas for stimuli depicting physical inactivity compared to the other conditions. However, we did not find evidence of approach biases towards physical inactivity, the involvement of the reward circuit in the processing of inactivity, or the activation of the conflict monitoring or inhibition circuits for avoiding inactivity. Keywords: physical activity, physical inactivity, effort minimization, approach-avoidance task, functional magnetic resonance imagining (fMRI)