We compared the exercise ventilatory response (slope of the ventilation, V̇E and carbon dioxide production, V̇CO2 relationship) in boys and girls with and without obesity. 46 children with obesity (BMI percentile: 97.7 ± 1.4) and 27 children without obesity (BMI percentile: 55.1 ± 22.2) were included and divided into groups by sex (with obesity: 17 girls and 29 boys; without obesity: 13 girls and 14 boys). A 6 min constant load cycling test at 45 % of peak work rate was performed. The V̇E/V̇CO2 slope was similar (p = 0.67) between children with (32.7 ± 4.3) and without (32.2 ± 6.1) obesity; however, it was higher (p = 0.02) in girls (35.4 ± 5.6) than boys (32.6 ± 4.9). We also examined a corrected V̇E/V̇CO2 slope for the effects of mechanical dead space (VDM), by subtracting V̇DM from V̇E (V̇Ecorr/V̇CO2 slope). The V̇Ecorr/V̇CO2 slope remained similar (p = 0.37) between children with (26.8 ± 3.2) and without obesity (26.1 ± 3.1); however, no sex differences were observed (p = 0.13). Therefore, VDM should be accounted for before evaluating the V̇E/V̇CO2 slope, particularly when making between-sex comparisons.
- Dead space
- Exercise ventilatory response
ASJC Scopus subject areas
- Pulmonary and Respiratory Medicine