HEART RATE RECOVERY IN CHILDREN FOLLOWING AEROBIC EXERCISE

In adults, the manner in which heart rate (HR) recovers form aerobic exercise is related to aerobic fitness, such that the higher the level of aerobie fitness the faster the HR recovery. In children it is not clear whether a similar relationship exists; thus, this study examined the relationship between HR recovery and maximal oxygen uptake (VO2max) in 16 boys (n = 8) and girls (n = 8) with a mean age of 10.8 ± 0.7 yrs. VO2max was measured during graded exercise on a cycle ergometer. On 2 subsequent days the children performed the following cycle ergometer protocols: (1) 3 min warm-up at 40% VO2max, 2 min rest, 5 min exercise at 85–90% of VO2max, 2 min cooldown at 40% VO2max, and 3 min rest, and (2) 3 min warm-up at 40% VO2max, 2 min rest, 5 min exercise at 70 watts (W), 2 min cooldown at 25 W and 3 min rest. HR was assessed at 1 and 3 min post-exercise and HR recovery was calculated as a percentage of the exercising HR. Testing order was counterbalanced. Gender differences were analyzed with an independent t-test. Simple correlations were used to examine the relationship between VO2max and HR recovery. VO2max averaged 40.0 ± 5.1 ml·kg−1 min1 in the girls and 46.0 ± 6.3 ml·kg−1 min−1 in the boys (p > 0.05). After exercise at 85–90% of VO2max, HR averaged ∼80% of the exercise HR at 1 min into recovery and ∼60% at 3 min into recovery in both groups (p > 0.05). Nearly identical results were observed following the 70 W intensity. The correlations between VO2max and HR recovery following exercise at 85–90% of VO2max were r = −0.17 and r = −0.08 at 1 and 3 min, respectively, after exercise (p > 0.05). At 70 W the correlations between VO2max and HR recovery were r = −0.28 at 1 min post exercise and r = −0.12 at 3 min following exercise (P > 0.05). These results do not support the notion that HR recovery is related to aerobic fitness in children. Using HR recovery as a means to quantify aerobic fitness in this age group is not recommended.