Suffering from somatic symptoms can seriously hamper one's quality of life and ability to function, causing lost work productivity, sickness absence, and extensive medical utilization. Physical activity (PA) has demonstrated promising results related to mild to moderate cases of somatic symptoms. The present study explored whether a worksite health promotion intervention was able to increase PA and cardiorespiratory fitness, and to reduce somatic symptoms and sickness absence. The intervention was designed based on the tenets of Self-determination theory. A pre-post cluster randomized controlled trial was conducted with 202 industrial workers in a Norwegian logistics company. Results from repeated measures, multivariate analysis of variance, revealed an overall intervention effect and significant change between groups related to somatic symptoms in favor of the intervention group, albeit no significant change in sickness absence. We applied structural equations modeling to test a model of health behavioral change, which posited that increased support for PA from coworkers and autonomous motivation for PA predicted changes in PA, cardiorespiratory fitness, and somatic symptoms. The results underline the effectiveness of including coworker social support in health promotion programs aimed to increase PA and reduce somatic symptoms. (PsycINFO Database Record (c) 2019 APA, all rights reserved).
Trial registration: ClinicalTrials.gov NCT02429635.