Criteria For Peak Effort During Graded Exercise Testing In Children And Adolescents With Obesity

Children and adolescents with obesity typically demonstrate reduced physical and cardiorespiratory exercise performance compared to normal weight counterparts. The gold standard to determine cardiorespiratory fitness (CRF) is the measurement of maximal oxygen consumption (VO2max) during a progressive exercise test. In the absence of a VO2 plateau often observed among children and adolescents, other criteria for maximal effort are used, including heart rate and respiratory exchange ratio. However, criteria to detect peak or maximal effort during exercise testing in children and adolescents with obesity are unclear. PURPOSE: To evaluate the achievement of peak-criteria for heart rate (HR-peak), respiratory exchange ratio (RER-peak), and rate of perceived exertion (RPE-peak) in Hispanic children with obesity. METHODS: Children enrolled in a weight control program completed body composition and cardiorespiratory fitness measures during a peak-exercise test on a cycle ergometer. Descriptive analyses included the proportion of children achieving specific estimated criteria for peak-effort. Independent t-tests were used to detect sex differences, and a secondary analyses tested differences between age groups: 7-12 vs 13-18 years. RESULTS: Participants (n = 29: 16 girls, 13 boys; age: 7-18 years) had a BMI above the 99th percentile. No BMI sex differences were observed. Mean VO2peak, HR-peak, and RER-peak were: 17.5 ml·kg-1·min-1, 172 bpm, and 1.10, respectively. All participants achieved an RPE ≥17. A predetermined HR-peak ≥180 bpm, and RER-peak ≥0.98 had the highest number of achievers (52% and 86%, respectively). No HR-peak criteria differences were observed between age groups, but 13-18 year-olds had a higher RER-peak compared with 7-12 year-olds. CONCLUSION: HR-peak ≥180 bpm, and RER-peak ≥0.98 could be expected at peak-effort during exercise testing among most children with obesity