In order to study on the optimum quantity of exercise for children in their daily life, we first gave a physical exercise performance test to 109 infants from 5 to 6 years of age and selected from them two groups of children, one comprising two children (a boy and a girl) who scored highest in the aforesaid test and the other also comprising two children (a boy and a girls) who scored lowest in the same test. We then carried on the measurement of heart rates in those four children while observing the behaviour and motion of the children at the same time. The results we obtained are follows:
(1) Total heart beats per day of each of the four children ranged from 138109 beats (95.9/min.) to 161847 beats (112.5/min.) and the highest-scoring children showed the small-est number of heart beats and the lowest-scoring child the largest number.
(2) Each of the four subjects registered the least average heart rate (67.9-93.3 beats/ min.) and the smallest alteration of heart rate at sleeping time. The average heart rate increased from 112.1-121.4 beats/min. in their home life to 122.8-135.4 beats/min. in their kindergarten life.
(3) The highest showed less than the lowest on the total heart beats. But the highest showed the higher heart rate in the physical education and outdoor free activity time at kindergarten than the lowest. As a result of behaviour observation of children, we also found out that they would seem to take more interest in activities that involved removal playthings such as bicycle ridding, rope skipping and etc.
(4) During sleeping time that accounted for about 42% of a day, the heart rate alter-ation was the least, accordingly we propose that the average heart rate at sleeping time may be an index of the heart rate of awake time, but It should be reguired more physio-logical investigations at sleeping time in future.