Movement behavior and mental health in office workers : Associations and intervention effects

Sammanfattning: Mental disorders pose a significant global health challenge. To effectively address this challenge, mental health promotion must be included in various sectors, including workplaces. Various strategies for promoting mental health in the workplace have been suggested, including interventions aimed at improving movement behavior, i.e., sitting less and moving more. Physical activity (PA) and sedentary behavior (SED) are established determinants of mental health. However, there are aspects of the relationship between movement behavior and mental health that are not well understood, for example, the combined effects of all movement behaviors occurring throughout the daily 24-hour cycle, i.e., time in bed, SED, light-intensity physical activity, and moderate to vigorous physical activity (MVPA), on mental health. In addition, only a few well-designed workplace interventions for improving movement and mental health outcomes have been tested. Office workers often spend extensive amounts of time being sedentary and might particularly benefit from such interventions. The aims of this thesis were (1) to investigate cross-sectional associations between 24-hour movement behavior and mental health among office workers and (2) to evaluate the efficacy, acceptability, feasibility, and fidelity of two cluster randomized controlled trial (RCT) interventions for improving movement behavior and mental health using quantitative and qualitative methods.In Paper I, we investigated cross-sectional associations between 24-hour movement behavior and mental health outcomes (symptoms of depression and anxiety, burnout, mental wellbeing, and stress) among office workers (N=345-370). Movement behavior was measured using accelerometers and sleep diaries. Mental health outcomes were assessed using validated questionnaires. Only the proportion of time spent in MVPA, relative to all other behaviors, was positively associated with mental wellbeing. Papers II-IV were based on a three-armed cluster RCT among office workers (N=263). During the 6-month intervention period, the iSED intervention group focused on reducing SED, and the iPA intervention group focused on increasing MVPA compared to a wait-list control group. The multi-level interventions were designed based on ecological models of health behavior, addressing the individual office workers as well as their physical, social, and organizational work environment. Paper II investigated intervention effects on accelerometer-measured 24-hour movement behavior and cardiorespiratory fitness. We considered overall 24-hour movement behavior and movement behavior during work versus non-work time. No intervention effects were found. Paper III was based on a qualitative study that was embedded in the RCT. It investigated the acceptability, feasibility, and fidelity of intervention components that addressed the individual, environmental and organizational level. Interviews and focus group discussions were performed with 38 key stakeholders after the 6-month intervention period. The study included office workers who received the interventions, health coaches who delivered counseling sessions, team leaders who were responsible for implementing group activities, and human resource and higher management staff who provided support at the organizational level. In general, the interventions were well appreciated, and components seemed to work as intended when delivered as intended. Many office workers experienced improvements in movement behavior and wellbeing and ascribed those to the interventions. Acceptability, feasibility, and fidelity of individual-level components were high but reduced for components depending on team leaders, mainly due to challenges associated with recruiting managers as team leaders and forming teams. Manager and team support were considered crucial for promoting more PA and less SED, yet many participants reported a lack of such support. Thus, identified challenges with these components might have reduced overall intervention efficacy. Paper IV investigated intervention effects on mental health outcomes (symptoms of depression or anxiety, mental wellbeing, and stress). In addition, we explored whether changes in mean PA intensity mediated or moderated intervention effects. The interventions improved mental wellbeing for the combined intervention groups and the iSED group but not for the iPA group compared to the control group. The interventions improved mean PA intensity, but mean PA intensity did not mediate intervention effects on any outcome. Mean PA intensity moderated intervention effects on mental wellbeing. Participants who reduced mean PA intensity reduced mental wellbeing compared to participants who did not change mean PA intensity. This highlights the importance of maintaining high levels of PA for mental wellbeing.This thesis contributes to existing knowledge by applying a rigorous investigation of cross-sectional associations between 24-h movement behavior and mental health among office workers and by conducting a comprehensive analysis of intervention effects. It offers valuable insights and considerations that may inform occupational health practitioners, employers, policy makers, and researchers and may contribute to developing future effective interventions.