Combined effect of body position, apparatus and distraction on children's resting metabolic rate.

OBJECTIVE: To verify the combined effect of body position, apparatus and distraction on children's resting metabolic rate (RMR). METHODS: Experiments were carried out on 14 children aged 8-12 (mean age = 10.1 years +/- 1.4). Each participant underwent two test sessions, one week apart under three different situations: a) using mouthpiece and nose-clip (MN) or facemask (FM); b) sitting (SEAT) or lying (LY); and c) TV viewing (TV) or no TV viewing. In the first session, following 20 min rest and watching TV, the protocol was: LY: 20 min stabilization; 10 min using MN and 10 min using FM. Body position was then changed to seated: 20 min stabilization; 10 min using FM; 10 min using MN. In the second session, FM and MN order was changed and participants did not watch TV. Data were analysed according to the eight combinations among the three studied parameters. RESULTS: Repeated measures ANOVA indicated statistically significant differences for VO2 (p =0.01) and RMR (p =0.02), with TVMNSEAT showing higher values than TVFMLY. Bland-Altman analysis showed a bias for VO2, VCO2, respiratory quotient (RQ) and RMR between TVFMLY and TVMNSEAT, respectively, of -17.8+/-14.5 (ml min), -8.8+/-14.5 (ml min), 0.03+/-0.05 and -115.2+/-101.9 (kcal/day). CONCLUSION: There were no differences in RMR measurements due to body position and apparatus when each variable was isolated. Analyses of distraction in three of four combinations indicated no difference between TV and no TV. Different parameter combinations can result in increased bias and variability, and thereby the reported differences among children's RMR measurement.