Abstract
This study explores the role of personal resources, specifically vigor at work (a positive affect generated by the ongoing interactions in the workplace) and weekly physical activity (PA), in the stress-mental health relationship, given the positive relationships found between PA and levels of vigor experienced on health. Thus, we hypothesized that vigor at work would mediate the relationship between job stress and workers' mental health, whereas weekly PA would moderate the relationship between stress and vigor at work. Five hundred and twenty-seven workers completed self-report scales for stress, weekly PA, vigor at work, and mental health. The results showed that vigor at work was related to better mental health, whereas stress was related to high psychological problems and low vigor at work. The interaction between stress and weekly PA on vigor was significant, indicating a counterproductive effect of weekly PA. Specifically, the negative relationship between stress and vigor at work was greater when doing weekly PA. In this vein, high levels of weekly PA would not have a favorable impact when workers experience high levels of stress, consuming part of vigor at work and reducing the positive effect of vigor at work on mental health by coping with stress.