Being more physically active is one of the goals that individuals set for themselves each year. Yet, even with knowledge of the risks associated with physical inactivity, they fail to turn their intentions into action. To explain and solve this paradox, psychologists and exercise scientists have developed theories and models based on goal setting, feedback and behavioral monitoring without much success as we are still facing a pandemic of physical inactivity. Recently, studies suggested that automatic approach (vs. avoidance) tendencies toward physical activity (PA) and inactivity stimuli are involved in the regulation of PA. The recent theory of effort minimization in physical (TEMPA) activity postulates that individuals are automatically attracted to behaviors minimizing energetic cost. These processes make sedentary behaviors more attractive, harder to avoid and more rewarding. However, the brain areas underpinning these automatic tendencies remain largely unknown. Here, we used an implicit approach-avoidance task (AAT) combined with high-resolution functional magnetic resonance imaging (fMRI) protocol to examine whether brain regions underpinning action inhibition and reward processing are associated with automatic approach tendencies toward PA and inactivity. At the behavioral level, results showed higher errors when avoiding physical inactivity stimuli compared to avoiding PA stimuli. Results further showed faster reaction times when responding to physical inactivity relative to PA stimuli when the state of craving for sedentary was high, irrespective of the type of response (i.e., approach or avoidance). At the neural level, stimuli depicting physical inactivity (vs neutral and physical activity) elicited and increased hemodynamic response in different regions related to primary and secondary visual areas. However, our results failed to observe significant activations of brain regions involved in action inhibition and reward processing during the approach-avoidance task. Future studies are required to investigate neural correlates of automatic approach-avoidance tendencies toward PA using an explicit, rather than an implicit, approach-avoidance task.