The effect of acute fluid consumption on measures of impedance and percent body fat using leg-to-leg bioelectrical impedance analysis.
OBJECTIVE
To examine the effect of acute fluid consumption on measures of impedance and percent body fat (%BF) using a common leg-to-leg bioelectrical impedance analyzer system.


METHODS
Cross-sectional design with treatment order determined using a counterbalanced assignment.


METHODS
University laboratory.


METHODS
In total, 21 recreationally active men (mean age 19.7 +/- 1.0 years; body mass index 24.2 +/- 2.3 kg/m2) volunteered to participate in this study.


METHODS
Subjects had their body composition assessed on three separate occasions. After an initial baseline body composition measurement, subjects consumed 591 ml of water (H2O), a carbohydrate/electrolyte drink (CHOE), or received nothing, used as the control (CON). Subjects were reassessed 20, 40, and 60 min after baseline (POST). Urine specific gravity (USG) was recorded at baseline and 60 min POST to assess hydration state.


RESULTS
There were no significant changes in impedance or total body water (TBW) for any of the measurement time periods after drinking H2O or a CHOE beverage. Body weight (BW) (P < 0.0001) and %BF (P < 0.02) increased significantly 20 min POST and remained elevated at the 40 and 60 min POST time periods. After drinking, USG significantly decreased (P<0.0001) 60 min POST from baseline. For the CON trial, there were no significant changes in BW, %BF, TBW, or USG over time.


CONCLUSIONS
Fluid consumption had no effect on lower-body impedance despite causing significant changes in hydration state. A slight overestimation in %BF (approximately 0.5%) was observed due to increased BW in the H20 and CHOE trials. This finding may have little practical significance when assessing body composition by LBIA.
Dixon
C B
CB
Department of Health Science, Lock Haven University, Lock Haven, PA 17745, USA. cdixon@lhup.edu
LoVallo
S J
SJ
Andreacci
J L
JL
Goss
F L
FL
D000273:Adipose Tissue / Q000502:physiology; D000328:Adult; D001823:Body Composition / Q000502:physiology*; D001834:Body Water / Q000378:metabolism / Q000502:physiology*; D018592:Cross-Over Studies; D003430:Cross-Sectional Studies; D004326:Drinking / Q000502:physiology*; D017097:Electric Impedance; D004573:Electrolytes / Q000378:metabolism; D006801:Humans; D008297:Male; D015203:Reproducibility of Results; D013997:Time Factors; D016482:Urinalysis
D004573:Electrolytes