Purpose: The period of early recovery after exercise is characterized by a rapid payback of the oxygen debt incurred during exercise. The purpose of this study was to test the hypothesis that the oxygen consumption (VO(2)) decline during the first minute of recovery after exercise will be faster in children with a higher peak VO(2).
Methods: We performed a clinically indicated bicycle exercise test in 203 children, aged 15.5 ± 3.2 yr; 33 had healthy heart/minimal heart disease, 59 had left-sided heart disease, 92 had right-sided heart disease, and 19 had postoperative single ventricle. VO(2) was recorded at peak exercise and at 20, 40, and 60 s of recovery.
Results: Peak VO(2) in the study cohort was 30.1 ± 8.5 mL·kg(-1)·min(-1) and fell to 24.3 ± 6.7, 19.5 ± 4.9, and 15.3 ± 4.0 mL·kg(-1)·min(-1) at 20, 40, and 60 s of recovery, respectively. VO(2) recovery was slower in children with right-sided heart disease and single ventricle compared with the other 2 groups and was faster in younger children, boys, children with a higher peak VO(2), and in those with a lower RER at peak exercise. In the linear regression analysis, the slope of VO(2) decline during the first minute of recovery was most strongly associated with the peak VO(2) (R(2) = 0.786, P < 0.001). The only other variable that added to the explained variance was peak RER (R(2) = 0.796, P = 0.004).
Conclusions: VO(2) decline during the first minute of recovery after maximum exercise is faster in children with higher peak VO(2). VO(2) recovery may be a useful tool in assessing cardiopulmonary health in children.