A multidimensional assessment of dyspnoea in healthy adults during exercise

Purpose (1) To determine whether healthy humans can distinguish between the intensity and unpleasantness of exertional dyspnoea; (2) to evaluate the reliability of qualitative dyspnoea descriptors during exercise; and (3) to assess the reliability of the Multidimensional Dyspnoea Profile (MDP) Methods Forty-four healthy participants (24M:20F, 25 +/- 5 years) completed maximal incremental cycling tests on three visits. During visit 1, participants rated the intensity and unpleasantness of dyspnoea simultaneously throughout exercise using the modified 0-10 category-ratio Borg scale. On visits 2 and 3, participants rated either the intensity or unpleasantness of dyspnoea alone at the same measurement times as visit 1. On all visits, participants selected qualitative descriptors throughout all exercise intensities from a list of 4, selected relevant qualitative descriptors from a list of 15 at peak exercise, and completed the MDP. Results Participants rated their dyspnoea intensity significantly higher for a given minute ventilation ((V) over dot(E)) compared to dyspnoea unpleasantness (dyspnoea-(V) over dot(E) slope: 0.08 +/- 0.02 vs. 0.07 +/- 0.03 Borg 0-10/L min-1, p < 0.001) during visit 1. The onset of intensity ratings occurred at a significantly lower work rate compared to unpleasantness ratings measured on the same exercise test (52 +/- 41 vs. 91 +/- 53 watts, p < 0.001). Dyspnoea intensity and unpleasantness remained significantly different for a given ventilation even when measured independently on separate exercise tests (p < 0.05). There was good-to-excellent reliability (ICC > 0.60) for the use of qualitative dyspnoea descriptors and the MDP to measure dyspnoea at peak exercise. Conclusion Exercise-induced dyspnoea in healthy adults can differ in the sensory and affective dimensions, and can be measured reliably using qualitative descriptors and the MDP.