Cardiorespiratory Fitness in Children with Obesity and Respiratory Symptoms
Authors: Wilhite Daniel , Bhammar Dharini , Martinez-Fernandez Tanya , Liu Yulun , Babb Tony 
Published: May 2024

Study Objective: Physical fitness (i.e., VȮ2max in ml/min/kg) is decreased in children with obesity. However, cardiorespiratory fitness (i.e., VȮ2max as a percent of predicted based on ideal body mass) is preserved in children with obesity. Unfortunately, many children with obesity suffer from obesity-related respiratory symptoms such as exertional dyspnea, which could make them reluctant to exercise and thus decrease both their physical fitness and cardiorespiratory fitness. Thus, we hypothesized that both physical fitness and cardiorespiratory fitness will be decreased in children with obesity and respiratory symptoms. Methods: Body composition (DXA) was measured on children aged 8-12yrs without obesity (‘CWOO’; n=25; 15th≤BMI≤85th percentile), with obesity (‘CWO’; n=49; BMI≥95th percentile), and with obesity and respiratory symptoms (‘CWORS’; n=14; BMI≥95th percentile). On a separate day, participants completed an incremental exercise test to volitional exhaustion. After 15min of seated rest, participants then performed a constant-load supramaximal verification test at 105% of the peak work rate. The highest VȮ2 from the incremental or verification test was recorded as VȮ2max. BMI-for-age data from the CDC were used to calculate ‘ideal’ body mass (BM) at the 50th percentile for CWO, CWORS, and CWOO who were above the 50th BMI percentile. Percent predicted VȮ2max was calculated using sex-specific prediction equations developed by Cooper et al. (2016). A one-way ANOVA with post hoc tests was used to determine differences among groups (i.e., CWOO, CWO, and CWORS). Significance was set at p < 0.05. Results: Age in years was slightly but significantly greater in CWOO (11.0±1.1) vs. CWORS (10.2±1.1), but similar between CWO (10.4±1.3) and the other two groups. Height was not significantly different between groups. BM in kg was similar between CWO (60.18±15.65) and CWORS (63.16±13.10), and significantly higher than CWOO (39.18±7.11). There were no significant differences in BMI (% of the 95th percentile), fat mass, % fat, or circumference measures between CWO and CWORS. VȮ2max in L/min was not different between groups (CWOO, 1.48±0.35; CWO, 1.59±0.32; CWORS, 1.57±0.30). VȮ2max in % predicted was not different between groups (CWOO, 97±12; CWO, 96±12; CWORS, 91±12). VȮ2max in ml/min/kg was similar between CWO (27.0±3.7) and CWORS (25.2±3.5), but significantly greater in CWOO (37.9±7.1) vs. the other two groups. Conclusion: Cardiorespiratory fitness is not affected in children with obesity and respiratory symptoms. Thus, the origin of symptoms in children with obesity and respiratory symptoms is probably not related to deconditioning. These findings are important to inform healthcare providers who examine fitness and associations with chronic disease in children with obesity. NIH R01 HL136643, King Charitable Foundation Trust, Cain Foundation, unrestricted gift from Dr. Pepper Snapple, and Texas Health Presbyterian Hospital Dallas. Dr. Daniel Wilhite was funded by an NIH Administrative Supplement to Promote Diversity in Health-Related Research (HL136643-01S1). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.