Is bioelectrical impedance spectroscopy accurate in estimating total body water and its compartments in elite athletes?

• Published in: Annals of human biology Vol. 40; no. 2; pp. 152 - 156
• Main Authors: Matias, Catarina N., Santos, Diana A., Gonçalves, Ezequiel M., Fields, David A., Sardinha, Luís B., Silva, Analiza M.
• Format: Journal Article
• Language: English
• Published: England Informa Healthcare 01.03.2013; Taylor & Francis
• Subjects: Adolescent; Athletes; Body composition; Body Water - metabolism; Bromides - chemistry; Deuterium - chemistry; deuterium oxide; Dielectric Spectroscopy - methods; dilution techniques; Electric Impedance; extracellular water; Female; Humans; Indicator Dilution Techniques; intracellular water; Male; Portugal; sodium bromide; total body water; Young Adult; Portugal
• ISSN: 0301-4460; 1464-5033; 1464-5033
• DOI: 10.3109/03014460.2012.750684

Background: Bioelectrical impedance spectroscopy (BIS) provides an affordable assessment of the body's various water compartments: total body water (TBW), extracellular water (ECW) and intracellular water (ICW). However, little is known of its validity in athletes. Aim: To validate TBW, ECW and ICW by BIS in elite male and female Portuguese athletes using dilution techniques (i.e. deuterium and bromide dilution) as criterion methods. Subjects and methods: Sixty-two athletes (18.5 ± 4.1 years) had TBW, ECW and ICW assessed by BIS during their respective pre-season. Results: BIS significantly under-estimated TBW by 1.0 ± 1.7 kg and ICW by 0.9 ± 1.9 kg in relation to the criterion methods, with no differences observed for ECW. The values for the concordance correlation coefficient were 0.98 for TBW and ECW and 0.95 for ICW. Bland-Altman analyses revealed no bias for the various water compartments, with the 95% confidence intervals ranging from − 4.8 to 2.6 kg for TBW, − 1.5 to 1.6 kg for ECW and − 4.5 to 2.7 kg for ICW. Conclusions: Overall, these findings demonstrate the validity of BIS as a valid tool in the assessment of TBW and its compartments in both male and female athletes.