Effort/reward imbalance and sedentary lifestyle: an observational study in a large occupational cohort

Of the major work stress models, the effort/reward imbalance (ERI) model ^{1- 3} is the most contemporary. The model posits that effort at work is spent as a part of a contract based on the norm of social reciprocity. Rewards are distributed by three transmitter systems: money (adequate salary), esteem (for example, respect and support), and security/career opportunities (for example, promotion prospects, job security, and status consistency). Imbalance between high efforts and low rewards defines work stress, a condition that in the long run is assumed to increase illness susceptibility. The model has predicted several ill health outcomes, such as cardiovascular morbidity and mortality, psychosomatic symptoms, and psychiatric disorder among a wide range of working populations with diverse sociodemographic profiles. ⁴ Of health behaviours and characteristics, smoking, ^{5, 6} alcohol dependence, ⁷ and higher body mass index ^{8, 9} have been associated with higher ERI.

Little is known whether high ERI also increases the risk for sedentary lifestyle. High cost/low gain conditions at work, such as having a demanding but an unstable job, or achieving at a high level without being offered any promotion prospects ¹⁰ could generate feelings of frustration and general passivity and apathy, which might spill over to leisure time. The alienation from work could result in social disengagement and adoption of unhealthy behaviours such as sedentary lifestyle. ¹¹ Indeed, the association between passive work and lower leisure time physical activity has received support in earlier studies. ^{12, 13}

To date, the Whitehall II study of British civil servants is probably the only investigation that has tested the association between ERI and physical activity, although examining this association was not the main goal of the study. ¹⁴ Unexpectedly, in this study people who exercised reported a less favourable effort-reward ratio at work.

The present study examined the association between ERI and sedentary lifestyle and tested whether ERI links with physical inactivity independent of job strain as defined by a ratio of job demands to job control ¹⁵ as prior research on work stress and physical activity mainly relates to the model of job strain.

METHODS

Study design and study population

Cross sectional data were obtained from the Finnish Public Sector Study, an ongoing prospective study to explore the relation of behavioural and...