Aerobic Fitness, Heart Rate Recovery and Heart Rate Recovery Time in Indian School Children.

Data on aerobic fitness and heart rate recovery in children are limited. This study was done to evaluate the relation between them in Indian school going children. Three hundred children of 7 to 10.5 years were recruited and their aerobic fitness was predicted using modified Harvard's step test (VO₂max) and 20 meter shuttle test (VO₂peak). The heart rate was monitored for 12 minutes post modified Harvard's step test. The difference between the maximum and the 1st minute HR was noted as HRR1 and the time taken to reach the resting heart rate was also recorded. VO₂max was inversely correlated with HRR1 (r = -0.64, p<0.001). However, the partial correlation of the two was not significant (r(partial) = -0.037, p = 0.55), indicating children with higher basal HR had higher HRR1 and that accounted for the observed association with aerobic fitness. Cox regression analysis showed that the recovery rate per unit time was 3% greater with increasing VO₂max (HR = 1.03, 95% CI:1.01 to 1.05, p = 0.013). The heart rate parameters did not show any associat with VO₂peak This study demonstrates that there is no relation between VO₂max and HRR1 after 3 minutes of modified Harvard's step test in Indian children of 7 to 10.5 years. However, aerobic fitness is a positive predictor of heart rate recovery time in this group.