Ventilatory response and dyspnea on exertion in children with obesity and respiratory symptoms

We investigated whether the exercise ventilatory response is associated with dyspnea on exertion (DOE) in children with (CWO;n = 25) and without (CWOO;n = 49) obesity, and with obesity and respiratory symptoms (CWORS;n = 14). The ventilatory response to exercise (V̇_E/V̇CO₂ slope) and ratings of perceived breathlessness (RPB, Borg 0-10 scale) were measured during 6-min cycling at 45 % maximal work rate. The V̇_E/V̇CO₂ slope (CWOO=34 ± 7; CWO=34 ± 5; CWORS=37 ± 6) and RPB (CWORS=4.0 ± 3.4; CWOO=2.5 ± 1.7; CWO=3.2 ± 2.1) were similar among groups (p > 0.05). A significant association between the V̇_E/V̇CO₂ slope and RPB in CWORS (r²=0.49;p < 0.05) was observed. To investigate this relationship more closely, children with an RPB≤ 2 were classified as having no or mild DOE (-DOE;n = 39;RPB=1.2 ± 0.7), and those with RPB≥ 3 were classified as having moderate to severe DOE (+DOE;n = 49;RPB=4.7 ± 1.9). +DOE had a higher V̇_E/V̇CO₂ slope (+DOE=36 ± 6;-DOE=33 ± 5;p = 0.02), higher breathing frequency, and higher V̇_E (%max;p < 0.05). These findings suggest a heightened sensitivity to ventilatory demand among children, and that +DOE may be driven by factors other than obesity alone, possibly increased ventilatory response to exercise.