Psychosocial, Environmental, and Functional Capacity Determinants of Psychological Workload in Retail Workers: A Multidomain Assessment Using a Digital Tool

Retail service workers face complex occupational demands across psychosocial, environmental, and physical domains; however, integrated multidomain workload assessments remain limited. A cross-sectional study among 253 retail workers used the Find My Stress Progressive Web Application (PWA)—a digital tool assessing subjective workload (Subjective Workload Index; SWI), psychosocial factors, environmental discomfort, musculoskeletal symptoms, and handgrip strength. Hierarchical multiple regression identified four significant SWI predictors: postural difficulty (β = 0.176, p = 0.012), workplace bullying (β = 0.175, p = 0.008), task duration (β = −0.179, p = 0.004), and air quality (β = 0.171, p = 0.011; Adjusted R2 = 0.199, ΔR2 = 0.227, p < 0.001; VIF: 1.03–1.57). Grip strength was retained as a functional capacity indicator. Sex-stratified analyses revealed distinct risk profiles: postural difficulty and task duration predicted SWI in men (Adjusted R2 = 0.224); workplace bullying was the sole predictor in women (Adjusted R2 = 0.170). The PWA demonstrated excellent reliability (α = 0.97) and usability (87%; n = 359). The Find My Stress PWA provides a scalable platform for multidomain stress screening. Integrated ergonomic, organisational, and environmental interventions guided by digital screening offer targeted strategies for reducing occupational workload burden in retail settings.