The Effect of Acute Fluid Consumption on Percent Body Fat using SBIA in Children

Abstract

PURPOSE: To examine the effect of acute fluid consumption on percent body fat (%BF) using segmental bioelectrical impedance analysis (SBIA) in children. METHODS: Sixty-six children (30 girls; 36 boys) between 7 and 16 years of age participated in this study. Subjects had their %BF assessed by SBIA on three separate occasions. After a baseline measurement, subjects consumed 12 oz (355 ml) of water (H2O), a carbohydrate/electrolytic drink (CHOE), or received nothing which was used as the control (CON). Subjects were reassessed 20, 40, and 60 minutes after baseline measure in each fluid condition. RESULTS: Twenty-minutes after drinking, %BF (mean difference = 1.0 and 1.0%), impedance (mean difference = 17 and 18Ω) and body mass (mean difference = 0.3 and 0.3 kg) increased significantly (p<0.05) and remained elevated at 40 and 60 minutes in the H2O and CHOE trials, respectfully. During the CON trial, %BF (mean difference = 0.4, 0.7 and 0.9%) and impedance (mean difference = 8, 16 and 21Ω) also increased significantly (p<0.05) above baseline values at 20, 40, and 60 minutes. However, the 20 minute variability for %BF and impedance during the CON trial was significantly (p<0.05) less than the fluid-induced alterations. Fluid type had no effect on the magnitude of change after drinking. CONCLUSIONS: Twenty minutes after drinking, %BF estimates increased approximately 1.0% due to elevations in impedance and body mass. Our findings are consistent with previous research in adults. Although the magnitude of the %BF change may have limited practical significance, we recommend adhering to the fluid restriction guideline prior to the SBIA measurement when precision is critical.