Heart Rate Response and Variability Following Maximal Exercise in Overweight Children

This study examined heart rate recovery (HRR) and heart rate variability (HRV) following maximal exercise in lean (<85th percentile age- and sex-BMI percentile; n = 11 (♂=5; ♀=6); 10.1 ± 0.7 years) and overweight (≥85th age- and sex-BMI percentile; n = 11 (♂=5; ♀=6); 10.5 ± 1.2 years) children.

Participants completed a 10-min rest, followed by a graded exercise test to maximal effort. HRV, in the time and frequency domains, was assessed during rest and recovery. Also during recovery, one-minute HRR and the time constant of a monoexponential line of best fit (HRRt) were determined.

There were no significant differences in one-minute HRR and HRRt between the lean (56 ± 7 beats∙min^-1 and 160.4 ± 80.1 s, respectively) and overweight (51 ± 16 beats∙min^-1 and 141.1 ± 58.1 s, respectively) groups. There also were no significant interactions between groups from rest to recovery for any HRV variables. Root mean square of successive differences (RMSSD) and high frequency power (HF) during recovery was 2.05 ± 0.49 ms and 3.30 ± 1.02 ms² in the lean children, respectively. In the overweight children, RMSSD and HF were 1.88 ± 0.65 ms and 2.94 ± 1.27 ms², respectively.

HRR and HRV findings suggest there are no differences in autonomic function during recovery from maximal exercise in lean and obese 8- to 12-year old children.