Abstract
Why do individuals fail to exercise regularly despite knowledge of the risks associated with physical inactivity? Automatic processes regulating exercise behaviors may partly explain this paradox. However, these processes have only been investigated with purely behavioral paradigms. Here, using electroencephalography, we investigated the cortical activity underlying automatic approach and avoidance tendencies toward stimuli depicting physical activity and sedentary behaviors in 29 young adults who were physically active (n=14) or physically inactive but with the intention of becoming physically active (n=15). Behavioral results showed faster reactions when approaching physical activity compared to sedentary behaviors, but faster reactions when avoiding sedentary behaviors compared to physical activity. These faster reactions were more pronounced in physically active compared to inactive individuals and were associated with changes during sensory integration (earlier onset latency and larger positive deflection of the stimulus-locked lateralized readiness potentials) but not during motor preparation (no effect on the response-locked lateralized readiness potentials). Faster reactions when avoiding sedentary behaviors compared to physical activity were also associated with higher conflict monitoring (larger early and late N1 event-related potentials) and higher inhibition (larger N2 event-related potentials), irrespective of the usual level of physical activity. These results suggested that additional cortical resources were required to counteract an innate tendency to approach sedentary behaviors.
Significance statement Our reactions to stimuli related to physical activity and sedentary behaviors depend on interactions between conscious intentions and automatic processes. For the first time, we investigated the cortical activity underlying automatic reactions in exercise behavior. Our results revealed that faster reactions to approach physical activity and avoid sedentary behaviors were explained by brain processes occurring during sensory integration, not during motor preparation. However, avoiding stimuli depicting sedentary behaviors required more cortical resources than avoiding stimuli depicting physical activity. These additional cortical resources were recruited to monitor cortical conflicts and increase cortical inhibition of automatic reactions. Contrary to behavioral results, these findings suggested that additional brain resources are required to escape an innate attraction toward sedentary behaviors and increase our level of physical activity.
Key points
Individuals, especially the physical active ones, showed faster reactions when approaching physical activity compared to sedentary behaviors, but faster reactions when avoiding sedentary behaviors compared to physical activity.
These faster reactions were associated with changes during sensory integration, but not during motor preparation.
However, faster reactions when avoiding sedentary behaviors compared to physical activity were associated with higher conflict monitoring and higher inhibition, irrespective of the usual level of physical activity.
These findings suggest that brain resources are required to escape an innate attraction toward sedentary behaviors and increase our level of physical activity.
Author contributions: Study design: BC, RR, MPB. Data collection: BC, ET. Data analysis: BC, ET, JF, NB, DO, MPB. Draft preparation: BC, MPB. Figures preparation: JF, NB, DO, MPB. Manuscript edition: BC, ET, NB, JF,DO, RR, MPB
