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Human hydration indices: acute and longitudinal reference values.
Int J Sport Nutr Exerc Metab 2010; 20(2):145-53IJ

Abstract

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 > or = 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.

Authors+Show Affiliations

Human Performance Laboratory, University of Connecticut, Storrs, CT, USA.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

20479488

Citation

Armstrong, Lawrence E., et al. "Human Hydration Indices: Acute and Longitudinal Reference Values." International Journal of Sport Nutrition and Exercise Metabolism, vol. 20, no. 2, 2010, pp. 145-53.
Armstrong LE, Pumerantz AC, Fiala KA, et al. Human hydration indices: acute and longitudinal reference values. Int J Sport Nutr Exerc Metab. 2010;20(2):145-53.
Armstrong, L. E., Pumerantz, A. C., Fiala, K. A., Roti, M. W., Kavouras, S. A., Casa, D. J., & Maresh, C. M. (2010). Human hydration indices: acute and longitudinal reference values. International Journal of Sport Nutrition and Exercise Metabolism, 20(2), pp. 145-53.
Armstrong LE, et al. Human Hydration Indices: Acute and Longitudinal Reference Values. Int J Sport Nutr Exerc Metab. 2010;20(2):145-53. PubMed PMID: 20479488.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Human hydration indices: acute and longitudinal reference values. AU - Armstrong,Lawrence E, AU - Pumerantz,Amy C, AU - Fiala,Kelly A, AU - Roti,Melissa W, AU - Kavouras,Stavros A, AU - Casa,Douglas J, AU - Maresh,Carl M, PY - 2010/5/19/entrez PY - 2010/5/19/pubmed PY - 2010/6/23/medline SP - 145 EP - 53 JF - International journal of sport nutrition and exercise metabolism JO - Int J Sport Nutr Exerc Metab VL - 20 IS - 2 N2 - 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 > or = 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. SN - 1526-484X UR - https://www.unboundmedicine.com/medline/citation/20479488/Human_hydration_indices:_acute_and_longitudinal_reference_values_ L2 - https://medlineplus.gov/urineandurination.html DB - PRIME DP - Unbound Medicine ER -