RESUMEN
Employees' work satisfaction and mental health are crucial for an organization's productivity. The current experimental study on employees (Ntotal = 278) from different professional sectors and workplaces in Germany investigated how to improve both by changes of daily non-work-related smartphone use time and physical activity time. For one week, the smartphone group (N = 73) reduced its daily smartphone use by one hour, the physical activity group (N = 69) increased its daily physical activity by 30 minutes, the combination group (N = 72) followed both interventions, the control group (N = 64) did not change its behavior. Online surveys assessed work-related and mental health-related variables at three measurement time points (baseline; post-intervention; two-week follow-up). The reduction of smartphone use time and the combination of both interventions increased work satisfaction, work motivation, work-life balance, and positive mental health significantly; experience of work overload and problematic smartphone use significantly decreased. All interventions decreased depressive symptoms and enhanced sense of control significantly. Following the present findings, a conscious and controlled reduction of non-work-related smartphone use time and its combination with more physical activity could improve employees' work satisfaction and mental health in the organizational context either as an addition to established training programs or as a separate time- and cost-efficient low threshold program.