Standardizing infrared thermography for occupational applications: an integrative narrative review of protocol quality, thermal metrics, and multimodal integration in work-related musculoskeletal disorders

Work-related musculoskeletal disorders (WMSDs) are a major occupational health burden, yet early functional alterations are often difficult to capture with symptom-only screening or with predominantly structural imaging. Infrared thermography (IRT) provides a noncontact, nonionizing, physiologically grounded readout of superficial heat exchange that is strongly influenced by microperfusion and autonomic vasomotor control. We conducted an integrative narrative review with traceable study-level compilation to synthesize physiological foundations for thermal-signal interpretation, minimum requirements for acquisition standardization and Quality Control, and occupational applications for screening, risk characterization, and longitudinal monitoring, including multimodal integration. The final included corpus comprised 247 studies spanning diverse designs and contexts, with substantial heterogeneity in devices, regions of interest (ROIs), environmental conditions, thermal metrics, and reporting completeness. Across the evidence, interpretability was consistently dependent on protocol stability and on ROI-based, within-subject metrics [bilateral asymmetry, task-induced temperature difference (ΔT), and recovery dynamics] rather than isolated absolute thresholds. Occupational applications have most often targeted repetitive upper-limb demands, computer-based work, and cold challenge/rewarming paradigms in vibration-exposed populations. We provide an operational checklist aligned with guideline recommendations and propose a pragmatic multimodal workflow integrating IRT with functional measures [surface electromyography (sEMG), strength], structural/perfusion modalities (ultrasonography), and patient-reported outcomes. Future priorities include multicenter harmonization, occupation- and task-specific reference profiles, and prospective validation of decision rules under real-world conditions.