Elimination of urine in response to water intake is consistent in well-hydrated individuals
A simple method has been recently proposed to assess acute hydration status in humans; however, several questions remain regarding its reliability, validity, and practicality.
Objective: Establish reliability of a simple method to assess euhydration, that is, to analyze whether this method can be used as a consistent indicator of a person´s hydration status. In addition, the study sought to assess the effect exercise has on urine volume when euhydration is maintained and a standardized volume of water is ingested.
Methods: Five healthy physically active men and five healthy physically active women, 22.5 ± 2.3 years of age (mean ± standard deviation) reported to the laboratory after fasting for 10 hours or more on three occasions, each one week apart. During the two identical resting euhydration conditions (EuA and EuB), participants remained seated for 45 minutes. During the exercise condition (EuExer), participants exercised intermittently in an environmental chamber (average temperature and relative humidity = 32 ± 3°C and 65 ± 7%, respectively) for a period of 45 minutes and drank water to offset loss due to sweating. The order of treatments was randomized. Upon finishing the treatment period, they ingested a volume of water equivalent to 1.43% body mass (BM) within 30 minutes. Urine was collected and measured henceforth every 30 minutes for 3 hours.
Results: Urine volume eliminated during EuExer (1205 ± 399.5 ml) was not different from EuB (1072.2±413.1 ml) or EuA (1068 ± 382.87 ml) (p-value = 0.44). Both resting conditions were practically identical (p-value = 0.98) and presented a strong intraclass correlation (r = 0.849, p-value = 0.001). Conclusions: This method, besides simple, proved to be consistent in all conditions; therefore, it can be used with the certainty that measurements are valid and reliable.
Armstrong, L., Casa, D., Millard-Stafford, M., Moran, D., Pyne, S., & Roberts, W. (2007). American College of Sports Medicine Position Stand: Exertional heat illness during training and competition. Medicine & Science in Sports & Exercise, 39(3), 556- 572. https://doi.org/10.1249/MSS.0b013e31802fa199
Capitán, C., & Aragón, L. (2009a). A practical method to assess euhydration [Abstract]. Medicine & Science in Sports & Exercise, 41(5), 11. https://doi.org/10.1249/01.mss.0000354256.05153.42
Capitán, C. y Aragón, L. (2009b). Método sencillo para comprobar euhidratación. Pensar en Movimiento: Revista de Ciencias del Ejercicio y la Salud, 7(1), 23-31. https://doi.org/10.15517/pensarmov.v7i1.374
Cheuvront, S. y Sawka, M. (2005). Evaluación de la hidratación en atletas. Sports Science Exchange, 18(2), 1-7.
Grandjean, A. y Campbell, S. (2004). Hidratación: líquidos para la vida. ILSI Norteamérica/ILSI de México, A. C.
Kovacs, E., Senden, J., & Brouns, F. (1999). Urine color, osmolality and specific electrical conductance are not accurate measures of hydration status during postexercise rehydration. Journal of Sports Medicine & Physical Fitness, 39(1), 47-53.
Oppliger, R. & Bartok, C. (2002). Hydration testing for athletes. Sports Medicine, 32(15), 959-971. https://doi.org/10.2165/00007256-200232150-00001
Sawka, M., Burke, L., Eichner, E., Maughan, R., Montain, S., & Stachenfeld, N. (2007). American College of Sports Medicine Position Stand: Exercise and fluid replacement. Medicine & Science in Sports & Exercise, 39(2), 377-390. https://doi.org/10.1249/mss.0b013e31802ca597
Shirreffs, S. (2003). Markers of hydration status. European Journal of Clinical Nutrition, 57 (Suppl 2), S6- S9. https://doi.org/10.1038/sj.ejcn.1601895
Ulate, G. (2007). Fisiología renal. Editorial UCR, San José, Costa Rica.
Wilmore, J. y Costill, D. (2004). Fisiología del esfuerzo y del deporte. Editorial Paidotribo, España.
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