Multidimensional breathlessness assessment during cardiopulmonary exercise testing in healthy adults

This study explored if healthy adults could discriminate between different breathlessness dimensions when rated immediately one after another (successively) during symptom-limited incremental cardiopulmonary cycle exercise testing (CPET) using multiple single-item rating scales.

Fifteen apparently healthy adults (60% male) aged 22 ± 2 years performed six incremental cycle CPETs separated by ≥ 48 h. During each CPET (at rest, every 2-min and at end exercise), participants rated different breathlessness sensations using the 0-10 modified Borg scale using one of six assessment protocols, randomized for order: (1) 'BREATHLESS_ALL' = breathlessness sensory intensity (SI), breathlessness unpleasantness (UN), work/effort of breathing (SQ_W/E), and unsatisfied inspiration (SQ_UI) assessed; (2) SI and UN assessed; and (3-6) SI, UN, SQ_W/E, and SQ_UI each assessed alone. Physiological responses to CPET were also evaluated.

Physiological and breathlessness responses to CPET were comparable across the six protocols, with the exception of SI rated lower at the highest submaximal power output (220 ± 56 watts) during the BREATHLESS_ALL protocol (0-10 Borg units 4.2 ± 1.7) compared to SI + UN (5.2 ± 2.1, p = 0.03) and SI alone (5.1 ± 1.9, p = 0.04) protocols. Ratings of SI and SQ_W/E were not significantly different when assessed in the same protocol, and were significantly higher than UN and SQ_UI, which were comparable.

In healthy younger adults, use of two separate single-item rating scales to assess breathlessness during CPET is feasible and enables the distinct sensory intensity and affective dimensions of exertional breathlessness to be assessed.