Recovery Responses to Maximal Exercise in Healthy-Weight Children and Children With Obesity

Purpose: The purpose of this study was to examine differences in heart rate recovery (HRRec) and oxygen consumption recovery (VO₂ recovery) between young healthy-weight children and children with obesity following a maximal volitional graded exercise test (GXTmax).

Method: Twenty healthy-weight children and 13 children with obesity completed body composition testing and performed a GXTmax. Immediately after the GXTmax, HRRec and VO₂ recovery were measured each minute for 5 consecutive minutes.

Results: There were no statistically significant group differences in HRRec for the 5 min following maximal exercise, Wilks's Lambda = .885, F(4, 28) = 0.911, p = .471, between the healthy-weight children and children with obesity despite statistically significant differences in body fat percentage (BF%; healthy-weight children, 18.5 ± 6.1%; children with obesity, 41.1 ± 6.9%, p < .001) and aerobic capacity relative to body mass (VO₂ peak; healthy-weight children, 46.8 ± 8.2 mL/kg/min; children with obesity, 31.9 ± 4.7 mL/kg/min, p < .001). There were statistically significant differences in VO₂ recovery for the 5 min following exercise, Wilks's Lambda = .676, F(4, 26) = 3.117, p = .032. There were no statistically significant correlations between HRRec and body mass index (BMI), BF%, VO₂peak, or physical activity.

Conclusions: In a healthy pediatric population, obesity alone does not seem to significantly impact HRRec, and because HRRec was not related to obesity status, BMI, or BF%, it should not be used as the sole indicator of aerobic capacity or health status in children. Using more than one recovery variable (i.e., HRRec and VO₂ recovery) may provide greater insight into cardiorespiratory fitness in this population.