Can a 6-month Intervention with a Sit-stand Desk Change Office Workers’ Bioelectrical Impedance Analysis-Derived Phase Angle? A Clustered Randomized Control Trial

Introduction: Phase angle (PhA) indicates cell integrity and functionality. High daily sedentary behavior (SB) levels negatively impact health. Sit-stand desk (SSD) interventions reduce sitting time in office workers. No previous study has analyzed the effect of SB reduction in office workers’ PhA. Purpose: This clustered randomized control trial examined changes in PhA in office workers after a 6-month SSD intervention coupled with motivational prompts. Methods: Thirty-eight office workers were assigned to the intervention and control groups. Bioelectrical impedance assessed resistance (R), reactance (Xc), and PhA scores. Results: PhA marginally improved in both groups (∆ ≈ 0.15). The intervention group showed a significantly reduced sitting time. No time interaction or differences between groups were found for PhA (p > 0.05). Conclusions: This SSD intervention coupled with motivational prompts failed to increase workers’ PhA. The marginal improvements in both groups suggest that SB reduction interventions may have to add strategies to increase activity levels to improve PhA levels.