The use of submaximal parameters in the assessment of exercise capacity in children with obesity

Summary Background Peak oxygen uptake (VO 2 ) is considered the most important indicator of aerobic exercise capacity during cardiopulmonary exercise testing (CPET). However, its accuracy is compromised when maximal effort is not achieved. In such cases, submaximal parameters can serve as surrogates for assessing exercise performance. Objectives To compare the differences in maximal and submaximal exercise parameters between children with obesity and normal weight. Methods A prospective study evaluating CPET using a treadmill completed by children with and without obesity. Results A total of 153 children (50.9% females) were divided into two groups: obese ( n = 87) and non‐obese ( n = 66). Children with obesity achieved lower exercise capacity (peakVO 2 of 68% ± 16% vs. 89% ± 15%; p < 0.0001) with fewer achieving maximal effort (26.4% vs. 78.7%, respectively). VO 2 ‐derived submaximal parameters showed a significantly lower oxygen uptake efficiency slope per body weight (OUES/kg) (30.5 ± 6.1 vs. 39.0 ± 9.5; p < 0.0001) and lower VO 2 at ventilatory threshold (VO 2 @AT) (21.2 ± 4.6 vs. 26.4 ± 5.3, p = 0.0001) in the obese group, with no significant differences in the CO 2 ‐derived parameters. Conclusions Maximal exercise data in children with obesity is frequently unavailable due to failure to achieve maximal effort. Submaximal parameters, such as OUES and VO 2 @AT, may be useful substitute options for assessing the health and functional level of this population.