Dyspnea during exercise and voluntary hyperpnea in women with obesity

Temporal responses of ratings of perceived breathlessness (RBP) during constant-load and incremental exercise, and during voluntary hyperpnea (EVH) were examined in women with obesity. Following 6 min of constant-load (60W) cycling, 34 women rated RPB≥4 (+DOE) and 22 women rated RPB≤2 (-DOE). Both groups completed an incremental cycling test and an EVH test at 40 and 60L/min; RPB was assessed each minute of incremental cycling and at the end of each EVH trial. RPB increased with ventilation during constant-load (+DOE: R²=0.86; -DOE: R²=0.82) and incremental (+DOE: R²=0.91; -DOE: R²=0.92) exercise, but + DOE had a greater y-intercept than -DOE (60W: -0.16±1.53 vs. -0.73±0.55; incremental: -0.50±1.40 vs. -1.71±0.84). Despite matching ventilation, RPB was greater in + DOE at baseline (0.97±1.14 vs. 0.14±0.28), 40L/min (2.50±1.43 vs. 0.98±0.91), and 60L/min (3.94±2.19 vs. 2.07±1.32) during EVH. These findings show that despite linear associations between RPB and ventilation during exercise and voluntary hyperpnea, breathlessness perception at a given ventilatory demand is heightened in +DOE compared with -DOE.