Human Hydration Indices: Acute and Longitudinal Reference Values
- Autores: Lawrence E. Armstrong, Amy C. Pumerantz, Kelly A. Fiala, Melissa W. Roti, Stavros A. Kavouras, Douglas J. Casa, Carl M. Maresh
- Localización: International journal of sport nutrition and exercise metabolism, ISSN 1526-484X, ISSN-e 1543-2742, Vol. 20, Nº. 2, 2010, págs. 145-153
- Idioma: inglés
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- Dialnet Métricas: 1 Cita
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Resumen
It is difficult to describe hydration status and hydration extremes because fluid intakes and excretion patterns of free-living individuals are poorly documented and regulation of human water balance is complex and dynamic. This investigation provided reference values for euhydration (i.e., body mass, daily fluid intake, serum osmolality; M ± SD); it also compared urinary indices in initial morning samples and 24-hr collections. Five observations of 59 healthy, active men (age 22 ± 3 yr, body mass 75.1 ± 7.9 kg) occurred during a 12-d period. Participants maintained detailed records of daily food and fluid intake and exercise. Results indicated that the mean total fluid intake in beverages, pure water, and solid foods was >2.1 L/24 hr (range 1.382�3.261, 95% confidence interval 0.970�3.778 L/24 hr); mean urine volume was >1.3 L/24 hr (0.875�2.250 and 0.675�3.000 L/24 hr); mean urine specific gravity was >1.018 (1.011�1.027 and 1.009�1.030); and mean urine color was =4 (4�6 and 2�7). However, these men rarely (0�2% of measurements) achieved a urine specific gravity below 1.010 or color of 1. The first morning urine sample was more concentrated than the 24-h urine collection, likely because fluids were not consumed overnight. Furthermore, urine specific gravity and osmolality were strongly correlated (r2 = .81�.91, p < .001) in both morning and 24-hr collections. These findings provide euhydration reference values and hydration extremes for 7 commonly used indices in free-living, healthy, active men who were not exercising in a hot environment or training strenuously.
