The contribution of office work to sedentary behaviour associated risk

Abstract

Background: Sedentary time has been found to be independently associated with poor health and mortality. Further, a greater proportion of the workforce is now employed in low activity occupations such as office work. To date, there is no research that specifically examines the contribution of sedentary work to overall sedentary exposure and thus risk. The purpose of the study was to determine the total exposure and exposure pattern for sedentary time, light activity and moderate/vigorous physical activity (MVPA) of office workers during work and non-work time.

Methods: 50 office workers from Perth, Australia wore an Actical (Phillips, Respironics) accelerometer during waking hours for 7 days (in 2008-2009). Participants recorded wear time, waking hours, work hours and daily activities in an activity diary. Time in activity levels (as percentage of wear time) during work and non-work time were analysed using paired t-tests and Pearson's correlations.

Results: Sedentary time accounted for 81.8% of work hours (light activity 15.3% and MVPA 2.9%), which was significantly greater than sedentary time during non-work time (68.9% p < 0.001). Office workers experienced significantly more sustained sedentary time (bouts >30 minutes) and significantly less brief duration (0-10 minutes) light intensity activity during work hours compared to non-work time (p < 0.001). Further, office workers had fewer breaks in sedentary time during work hours compared to non-work time (p < 0.001).

Conclusions: Office work is characterised by sustained sedentary time and contributes significantly to overall sedentary exposure of office workers.

Figure 1

Proportion of time in sedentary, light, moderate and vigorous activity on a work day (a), non-work day (b), work hours on a work day (c), non-work hours on a work day (d) and total non-work time over a whole week.

Figure 2

Exposure Variance Analysis showing proportion of wear time in sedentary, light and MVPA in bouts of 0- < 5, 5- < 10, 10- < 30 and 30+ minutes on a work day (a), non-work day (b), work hours on a work day (c), non-work hours on a work day (d) and total non-work time over a whole week (e).