The effect of a workplace intervention designed to interrupt prolonged occupational sitting on the health of desk-based employees

Increasingly, environments such as the workplace have evolved into settings where prolonged sitting has become ubiquitous, most commonly among desk-based employees. The proliferation of sitting behaviour in the workplace can be attributed to a confluence of factors such as easy access to personal desktop computers, printers, and photocopiers; comfortable office chairs; and shared open plan office spaces that restrict opportunities to perform alternate behaviour to sitting. Effortless access and the convenience of technology has engineered movement out of the workday for many employees and workplaces. Health research has identified a number of adverse effects associated with prolonged sitting such as increased risk of cardiovascular disease, increased all-cause mortality, and increases in indicators of metabolic syndrome; independent of adherence to recommended physical activity guidelines. Despite these negative associations, there is little evidence that workplace interventions have effectively addressed reducing sitting behaviour, or targeted the reduction of sitting as a primary outcome. To address these gaps, the effectiveness of a workplace intervention designed to interrupt sitting and increase short bouts of movement periodically throughout the workday was investigated in this thesis. The intervention depicted in this thesis is an interactive computer-based software program installed on the desktop computers of desk-based employees, predicated on a social ecological model that features a passive prompt to stimulate behaviour change by interrupting sitting at 45-minute intervals. To test the effectiveness of the intervention on the health of desk-based employees, two sets of participants were examined in separate studies. In the first study the influence of the intervention on participants' health was investigated by measuring self-reported energy expenditure and a battery of physiological biomarkers in an experimental group and a control group over a 13-week period. The participants were randomly assigned with replacement to either the experimental group who received the intervention (n = 20; mean age = 41.50 +/-12.39) or to the control group who did not (n = 26; mean age = 44.88 +/-9.65), and were full-time employees who worked eight-hour daily shifts and primarily had desk-based job responsibilities. Findings indicated that the intervention was effective in interrupting prolonged sitting and increasing short bouts of movement during the workday. This resulted in a significant increase in energy expenditure and a significant decrease in mean arterial pressure. There were no significant effects on the blood glucose, cholesterol, or triglyceride dependent variables. The second study built upon the objective measures of the first study by testing participant perceptions of health behaviour change in the workplace, and if this change was sustainable. The participants (N = 43; mean age = 43.81 +/-9.94) were full-time employees who worked eight-hour daily shifts and primarily had desk-based job responsibilities. Participant perceptions of health and compliance to the intervention were collected over 26 weeks across three repeated measures: pre-test, post-test, and retention test. To measure the sustainability of perceptions of health behaviour change in the workplace, the passive prompting feature of the intervention was removed between the POS test and the retention test. In addition to supplement these measures of health, qualitative semi-structured interview data were collected throughout the experimental period. Once the passive prompt was removed adherence to the intervention was significantly reduced. Despite this, participants' perceptions of improved health, which increased significantly when the intervention prompted them passively, remained high once the prompt was removed. This was further substantiated by the interview data, which indicated that employees were more likely to adhere to the program if they were continuously prompted to do so. This suggests that passively interrupting prolonged periods of sitting and increasing movement throughout the workday is efficacious in improving several outcomes associated with health; but if sustainable change in sitting behaviour in desk-based employees is to occur a passive stimulus is necessary.