Effects of standing workstations on occupational sedentary behaviour and metabolic health in office workers : a single-case study design

Abstract

Introduction: Metabolic Syndrome is a collection of clinical signs that represent unfavourable metabolic changes in the body. Metabolic syndrome has been associated with increasing risk of cardiovascular disease, Type II diabetes mellitus, stroke, and all-cause mortality. In recent years sedentary behaviour has been linked to markers of metabolic syndrome, cardiovascular disease and all-cause mortality. Research shows that the negative effects of sedentary behaviour are separate from the benefits of physical activity and that steps should be taken to mitigate harm by replacing sedentary behaviour with regular light intensity physical activity. For example, substituting sitting for standing.

Methods: This single-case design study investigated the effects of a sit-stand or standing workstation on physical activity and metabolic markers: central obesity, blood pressure, blood glucose, triglycerides and HDL cholesterol. Six occupationally sedentary participants aged between 25 and 40 years with a BMI between 25 and 30 kg/m2 were recruited from the Auckland population. During a 5 week baseline period, a 3 week ‘phase-in’ period and a 13 week intervention period, participants were assessed every 4 weeks using anthropometric and biochemical measurements in order to analyse any changes to the markers of metabolic syndrome. Inclinometry recorded during working hours was used to analyse changes to daily occupational sitting and standing duration . Results: Changes occurred for daily sitting and standing time for 5 participants. Standing time increased following the introduction of the standing workstation; the smallest increase was 111 min/day and the largest increase was 341 min/day. The smallest decrease in daily sitting time was 107 minutes and the largest decrease was 311 min/day. During the intervention period, the changes to daily sitting and daily standing times remained stable. Three participants showed decreases in waist circumference of between 2.5 and 6.7 cm. Meaningful changes in other metabolic markers were only seen in a single increase of blood glucose, and a single decrease of blood triglycerides.

Conclusion: The use of sit-stand or standing workstations reduced daily occupational sitting and increased daily occupational standing in all participants, where inclinometry data were available. These changes were stable across the entire intervention period suggesting high acceptability of the standing workstation. The failure to detect changes to metabolic markers may be suggestive of study limitations, such as duration, or the complexity of metabolic syndrome. Future studies may use randomising and control groups with a larger sample.