ABSTRACT
Since 1983, bioelectric impedance has been researched with respect to its validity and reliability in the determination of body composition. It continues to be compared to hydrostatic weighing, the anthropometric "gold standard". This study was designed to investigate the relationship between bioelectric impedance analysis (BIA) and hydrodensitometry (HW) under three conditions: control, hydration and dehydration. Caucasian males (aged 18-44 years) served as subjects (n = 10). Body composition was determined by BIA and HW before intervention, 30 minutes post-hydration, and following a combination of exercise and sitting in a steam room to decrease body weight by two to four percent (mean = 2.81%). Statistical treatment by two-way analysis of variance for repeated measures revealed that although there were no significant differences between the two techniques of body composition determination under any of the three conditions, there was a statistically significant decrease in percent body fat determined in the dehydrated state as compared to the control and hydrated conditions. Recommendations include the determination of hydration state prior to engaging in body composition analysis by either method.
Subject(s)
Body Composition/physiology , Body Water/physiology , Dehydration/physiopathology , Densitometry/methods , Adipose Tissue/physiology , Adolescent , Adult , Analysis of Variance , Anthropometry , Electric Conductivity , Humans , Male , MethodsABSTRACT
The Rayleigh factors and depolarization ratios at 6328 A have been measured for carbon disulfide, toluene, benzene, chloroform, carbon tetrachloride, cyclohexane, butanone, acetone, methanol, and water using an improved model of the low-angle laser light-scattering (LALLS) photometer. Small errors in some of the Rayleigh factors published using an earlier model of this instrument have been revealed. Depolarization ratios are measured by a new method involving detection of the full cone of forward scattered light.
