The measurement of resting metabolic rate in preschool children.

OBJECTIVE This study examined the repeatability of measuring resting metabolic rate (RMR) in preschool children and the effect of different calculation protocols. RESEARCH METHODS AND PROCEDURES Eleven children (4 females and 7 males) participated in the project. They were recruited through advertisements in local schools and community centers. Resting metabolic rate was measured on 3 occasions over a 2-week period, each after an overnight fast and each lasting approximately 20 to 25 minutes. Results were compared using repeated-measures ANOVA to check for repeatability, and a number of methods of calculating RMR were assessed. RESULTS Repeatability of RMR measurements was good (coefficient of variation of replicates, 6.8%), with no significant difference between days of measurement. The lowest RMR measurement was obtained when the first 10 minutes were excluded and periods during which large activity was observed were excluded. This measurement was, on average, 4% lower than averaging the measurements after the first 5 minutes, including body movements. DISCUSSION This study suggests that RMR can be measured in preschool children and that the best method for calculating RMR in these subjects is to exclude periods when large body movements occur and the first 10 minutes of the measurement period. Only a single measurement of RMR is needed to obtain a reliable estimate.