Defaults at Work: A Field Experiment on the Effect of Nudges on Stand-Up Working.

Sedentary behavior at work is a major, and growing, public health concern. This field experiment investigates the effectiveness of behavioral nudges, specifically default settings on height-adjustable workstations (HAWS), in promoting stand-up working behavior. It also examines whether transparency and health coaching enhance these effects. The study was conducted in a Belgian governmental organization and included 149 employees across eight departments. Departments were randomly assigned to one of four conditions: a non-transparent default nudge (NTDN), a transparent default nudge (TDN), a classical health coaching intervention, or a hybrid intervention combining TDN and coaching. Over an eight-week intervention period, employee posture was recorded using fixed camera snapshots taken every 30 min. These data were used to calculate the stand-up ratio. The NTDN increased stand-up rates from 1.82% to 4.93%. The TDN more than doubled this effect, reaching 11.25%. The combination of TDN and coaching produced the highest increase, with stand-up rates rising to 18.80% ( = 9.85). Coaching alone showed no significant effect. Although behavior partially regressed after the interventions were removed, post-measurement stand-up ratios after a week remained higher than baseline. These findings suggest that transparent default nudges, especially when combined with low-threshold coaching, can meaningfully reduce sedentary behavior in everyday office environments.