OCCUPATIONAL RESPIRATORY LOAD AND FUNCTIONAL SAFETY: A CRITICAL REVIEW OF INSPIRATORY MUSCLE TRAINING: OCCUPATIONAL RESPIRATORY LOAD AND FUNCTIONAL SAFETY: A CRITICAL REVIEW OF INSPIRATORY MUSCLE TRAINING
Synopsis
Sustained high respiratory load is recognised as a functional-safety issue in high-demand environments, yet remains underrepresented in occupational health. Constrained breathing, high inspiratory work and limited recovery may accelerate inspiratory muscle fatigue, increase perceptual strain and impair task execution. Inspiratory muscle training (IMT) has been proposed as a preventive strategy, but its effectiveness appears to depend on dose governance. Objectives: To critically appraise randomised controlled trials (RCTs) of IMT in competitive swimmers as a high-demand model, focusing on inspiratory muscle strength, functional capacity under respiratory load, pulmonary function and perceived exertion, and examine how dose governance influences safety-relevant outcomes. Methodology: A critical review of RCTs used a PICOT framework. Methodological quality was assessed using Oxford Levels of Evidence, the Physiotherapy Evidence Database (PEDro) scale and the Cochrane Risk of Bias 2.0 (RoB 2.0) tool. Results: Three RCTs were included (Oxford level 1b; PEDro 6–8/10; RoB 2.0: some concerns). Supervised IMT with progressive loading and documented adherence produced consistent improvements in inspiratory strength and functional-capacity markers, whereas weak dose verification was associated with absent or equivocal effects despite longer programme duration. Conclusions: IMT may support respiratory-load regulation and functional safety only under explicit and verifiable dose-governance conditions; duration alone is insufficient.
