Energy expenditure in prepubescent children: influence of sex and age.
The purpose of this investigation was to examine the relationship between energy expenditure and speed for 6-and 7-yr-old children and to compare these data to published data for adults. Eight subjects (n = four boys, four girls) completed three treadmill tests at 67, 94, and 127.5 m . min-1 (k = 12 trials for the boys, 12 trials for the girls). Heart rate was monitored continuously and oxygen uptake (VO2) and carbon dioxide production (VCO2) were determined at each speed in order to estimate caloric expenditure. Sex differences were observed in the metabolic and heart rate responses to exercise. In comparison to the females, the energy expenditure (kcal . min-1) was 16 (p less than 0.05), 11 (p greater than 0.05) and 14 (p less than 0.05) percent higher for the males at the slow, medium, and fast speeds, respectively. Additionally, heart rate was 13 beats . min-1 lower (p less than 0.05) for the males at a speed of 94 m . min-1. Differences in kcal . kg . min-1 between children and adults were observed (children higher). In contrast to adults' linear increase in energy expenditure with increasing speed, a curvilinear pattern was observed for prepubescent children. It was concluded that these sex and age effects must be considered when attempting to quantify children's daily energy expenditure and caloric requirements.
D000367:Age Factors; D002648:Child; D004734:Energy Metabolism; D005080:Exercise Test; D005260:Female; D006801:Humans; D008297:Male; D011627:Puberty; D012737:Sex Factors