Ventilatory drive modulates the temporal evolution of multidimensional dyspnoea during constant-load exercise in...

How increased ventilatory drive shapes the temporal evolution and multidimensional experience of exertional dyspnoea remains incompletely understood. This study examined whether experimentally increasing ventilatory drive via dead-space loading (DSL) alters dyspnoea during constant-load exercise. Nine healthy adults (7 male; V̇O_2peak 100 ± 16% predicted) performed constant-load cycle ergometry to task failure at 50%Δ between the gas-exchange threshold and V̇O_2peak under control (CTRL) and DSL (15% vital capacity) conditions in a randomised crossover design. Dyspnoea intensity, dyspnoea unpleasantness, and leg discomfort were assessed using the Borg CR10 scale, and sensory-perceptual and affective-emotional dimensions using the Multidimensional Dyspnoea Profile. Compared with CTRL, DSL increased end-tidal CO₂, minute ventilation, tidal volume, and inspiratory pressures without altering cardiometabolic responses, and reduced time to task failure (10.0 ± 2.3 vs. 13.8 ± 4.6 min; p = .012). Dyspnoea intensity rose more rapidly during DSL, but was similar at task failure, whereas dyspnoea unpleasantness was consistently higher without a distinct temporal divergence. Leg discomfort and dyspnoea descriptor frequencies did not differ between conditions. Post-exercise multidimensional profiling revealed greater breathing unpleasantness (p = .008), immediate perception scores (p = .036), respiratory work/effort (p = .040), and air hunger (p = .027), with no differences in emotional response scores. Greater iso-time increases in dyspnoea intensity and unpleasantness were associated with shorter time to task failure (r = - .82 to - 0.88; p ≤ .007). These findings suggest that increased ventilatory drive accelerates dyspnoea development and preferentially augments sensory-perceptual characteristics of dyspnoea, contributing to earlier task failure despite similar end-exercise symptom intensity.