Long-term effects of sit-stand workstations on workplace sitting: A natural experiment.

OBJECTIVE: Sit-stand workstations may result in significant reductions in workplace sitting. However, few studies have examined long-term maintenance under real-world conditions. The purpose of this study was to evaluate workplace sitting time, cardio-metabolic biomarkers, and work productivity during a workplace re-design which included the installation of sit-stand workstations.

DESIGN: Natural experiment with appropriately matched comparison.

METHODS: Office workers from distinct worksites in the same unit were recruited (Intervention, n=24; Comparison, n=12). Intervention arm participants received a sit-stand workstation and 4 months of sitting-specific motivational support. The comparison arm received 4 months of ergonomic focused motivational support. Time spent in sitting, standing, and other physical activity were measured by activPAL3c for a week. Cardio-metabolic biomarkers and work productivity were also measured. Assessments occurred at baseline, 4 months, and 18 months.

RESULTS: At 4 months, work sitting time was reduced by 56.7±89.1min/8h workday (d=-0.64), relative to comparison. Standing time (37.4±69.2min/8h workday; d=0.54) and sit-to-stand transitions (3.3±0.4min/8h workday, d=0.44) were also improved relative to comparison. At 18 months, work sitting time reductions (52.6±68.3min/8h workday; d=-0.77) and standing time improvements (17.7±54.8min/8h workday, d=0.32) were maintained in the intervention group relative to comparison. Cardio-metabolic and work productivity changes were mixed; however, strongest effects favoring the intervention group were observed at 18 months.

CONCLUSIONS: Sit-stand workstations, accompanied with behavioral support, were effective in reducing workplace and overall daily sitting and increasing standing time in a real-world setting. The effect appears to have been sustained for 18 months, with mixed results in cardio-metabolic and productivity outcomes.