Validation of Bioimpedance Spectroscopy to Assess Acute Changes in Hydration Status

• Autores: Karen J. Higgins, Phyllis M. Reid, Scott B. Going
• Localización: Medicine & Science in Sports & exercise: Official Journal of the American College of Sports Medicine, ISSN 0195-9131, Vol. 39, Nº. 6, 2007, págs. 984-990
• Idioma: inglés
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• Resumen

  • Purpose: To validate bioimpedance spectroscopy (BIS) as a field method for measuring small, acute changes in extracellular water (ECW) during a fluid fast/rehydration manipulation.

    Methods: Seventeen young adults (15 female, 2 male) participated in a 4-d fluid fast/rehydration protocol designed to induce acute changes in ECW. ECW change (?ECW), measured by bioimpedance spectroscopy (BIS-?ECW), was compared with ?ECW, measured by bromide dilution (Br-?ECW), and change in body weight (?BW).

    Results: Regardless of hydration status, BIS-?ECW and Br-?ECW were similar; during dehydration, the mean difference between these two methods was 0.16 kg (P = 0.61), and during rehydration, the mean difference was 0.58 kg (P = 0.06). Assuming that ?ECW = ?BW, ?ECW as estimated from ?BW differed significantly from Br-?ECW, but not from BIS-?ECW. In addition, BIS-?ECW correlated significantly with ?BW (r = 0.57 and 0.65 during dehydration and rehydration, respectively). However, the magnitude of ?ECW impacted the accuracy of BIS-?ECW because BIS measures tended to overestimate ?ECW at values between 0.0 and 1.0 kg and to underestimate changes at values above 1.0 kg.

    Conclusion: These findings suggest that BIS provides an accurate estimate of ?ECW compared with bromide dilution during short-term changes in hydration