Understanding energy balance in children is hampered by a lack of information regarding the actual energy expenditure of specific activities.
PURPOSE
to determine energy expenditure (EE) (in terms of oxygen uptake, caloric cost, and metabolic equivalents [MET]) of common childhood and adolescent activities and compare the results to information in the Compendium of Physical Activities (Ainsworth et al., 2000).
METHODS
295 youth 8–18 years of age completed 21 common physical activities while EE (oxygen uptake: VO2) was measured with a portable metabolic system.
RESULTS
Age and sex effects on resting VO2 were compared using an ANOVA. Resting VO2 declined significantly (p <0.0001) from age 8 (6.9 ml/kg/min) to 18 years and was still slightly above the Compendium value of 3.5 ml/kg/min at age 18 (4.0 ml/kg/min). Post hoc testing showed that VO2 was similar within age groups for boys aged 8 – 12 y (Group 1), 13–15 y (Group 2) and 16–18 y (group 3) and for girls: Group 1 = 8 – 11 y, Group 2 = 12–14 y, and Group 3 = 15–18 y. No differences in resting VO2 were found between sexes within the three age groups. VO2 for each activity declined with an increase in age, however the ratio of activity EE to at-rest EE (MET level) was similar in children and adolescents for most activities when compared to the adult Compendium values.
CONCLUSIONS
Our data indicate that resting and activity energy expenditure is greater in children than in adults, thus the adult Compendium estimates are inadequate for energy estimation in children, until a child reaches about age 15 in girls and 17 in boys. The ratio of activity EE to at-rest EE in children is similar to the adult compendium values, so published MET levels can be used with children if the values are corrected for their higher resting EE. The Compendium assumes that one MET for an adult is equal to 3.5 ml/kg/min. For children and adolescents this value should be corrected to 5.9, 4.6, and 4.0 ml/kg/min for age groups 1, 2, and 3, respectively. Supported by NINR Grant NR04564
