Effect of Sex on Reproducibility of Bioimpedance Derived Total Body, Extracellular, and Intracellular Fluid Volumes

Abstract

1669 Total body, extracellular, and intracellular fluid volumes are useful measures for some types of exercise physiology research. Previous research has indicated acceptable reproducibility of multifrequency bioelectrical impedance analysis (BIA) derived body fluid volumes in mixed populations. However, sex specific data has not been reported. Purpose: To examine the effect of sex on reproducibility of multifrequency BIA derived total body water (TBW), extracellular fluid (ECF), and intracellular fluid (ICF) volumes. Methods: Fourteen subjects (age = 26 ± 8 yrs, height = 172 ± 12 cm, weight = 77 ± 18 kg, 8 female) were assessed on five separate occasions over a two week period. Precautions included avoidance of data collection during one week prior to menses, an overnight fast, 12 hr abstention from alcohol, caffeine, and exercise, standardized measurement time (± 1 hr), electrode placement, and limb abduction. Following a 10- minute supine equilibration period single measurements of TBW, ECF, and ICF were performed.TableResults: For each variable for both sexes, intraclass correlation coefficients (ICC) were high, and showed no significant differences between any days. Coefficients of variation (CV) were low for each variable and for both sexes, indicating adequate sensitivity to detect small changes in fluid volumes (ranging from ± 0.3 L for female ICF to ± 1.4 L for male TBW). Conclusion: Sex has no effect on reproducibility of BIA derived TBW, ECF, and ICF when standardized precautions are taken. Multifrequency BIA would be useful to monitor the responses of body fluid volumes to training, nutritional, medicinal, or heat stress interventions in males and females.