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 obese women. Following 6 min of constant-load (60 W) 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 60 L/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 (60 W: -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), 40 L/min (2.50 ± 1.43 vs 0.98 ± 0.91), and 60 L/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.