Assessment of the influence of age on the rate of heart rate decline after maximal exercise in non-athletic adult males.

This study investigated the influence of age on heart rate (HR) decline after exercise in non-athletic adult males. One hundred and fourteen adult males (66 young, 25 +/- 6.26 years; 48 old, 53 +/- 8.54 years) participated in the study. Subjects performed maximum-effort ergometer exercise in incremental stages. HR was measured at rest and continuously monitored during and after exercise. Maximum oxygen uptake (VO(2max)) was measured during the exercise using respiratory gas analyser. Body mass index (BMI) was computed from weight and height measurements, while rating of perceived exertion (RPE) was obtained immediately after the exercise. Results indicated age differences in the rate of HR decline with the young presenting significantly higher %HR decline (P<0.001) than old adults at both levels of recovery. When linearly correlated with age, the rate of HR decline in 1 and 3 min indicated variances of (52%,56%) in young adults, and (54%,49%) in the old adults. After controlling for VO(2max), resting HR, BMI and RPE, the influence of age on rate of HR decline in the two phases of recovery disappeared in young. In the older adult group, it reduced greatly in the 1-min recovery (r(2) = 25%; P = 0.001) and disappeared in the 3-min recovery. Pattern of HR recovery did not differ between the two age groups while age threshold was observed in HR recovery in 1 min. In summary, the influence that age appeared to have on the rate of HR decline could not hold when factors affecting HR recovery were taken into account.