Objective Recent research has found conflicting interactions between health and different domains of physical activity (PA). Occupational physical activity (OPA) seems to negatively impact health,...Show moreObjective Recent research has found conflicting interactions between health and different domains of physical activity (PA). Occupational physical activity (OPA) seems to negatively impact health, whereas leisure-time physical activity (LTPA) positively impacts health, a phenomenon known as the physical activity paradox. What remains unclear is how these different domains of PA interact with each other and how their interaction influences health. Therefore, this study aims to investigate the main and interactive effects of OPA and LTPA on physical and mental health. A better understanding of these relations can contribute to more accurate PA advice, indirectly contributing to the closure of socioeconomic health inequalities. Based on previous studies, it was expected that higher OPA would relate to higher physical and mental health problems, while higher LTPA would relate to lower physical and mental health problems. Additionally, this study aimed to answer the research question whether LTPA functions as a buffer for the negative effects of high OPA on health or as an accelerator. Methods To investigate the hypotheses and research question, data from a longitudinal panel study were used. Two data measurement points were used with a one-year time lag. The sample was heterogeneous and consisted of Dutch employees working ≥ 24-hours a week (N = 1578). Results It was found that OPA and LTPA independently did not affect physical or mental health outcomes differently. Additionally, different combinations of OPA and LTPA did not lead to an increase or decrease in both physical mobility or mental health problems one year later. However, the results did show that individuals who had high levels of both OPA and LTPA had the highest chance on developing physical health problems one year later (b = 0.393, p = <0.001). Conclusion This study shows that OPA and LTPA may have different effects on the development of physical health problems, like headache and sleeping problems. The findings suggest that the health benefits of LTPA are affected by the extent of OPA and that a combination of both high OPA and LTPA is the most unfavourable combination. This combination is associated with an increase in physical health problems. Theoretical and practical implications are discussed.Show less
