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Human hydration indices: acute and longitudinal reference values.

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.

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Authors+Show Affiliations

,

Human Performance Laboratory, University of Connecticut, Storrs, CT, USA.

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Source

MeSH

Body Water
Circadian Rhythm
Color
Dehydration
Drinking
Humans
Hydrogen-Ion Concentration
Male
Osmolar Concentration
Reference Values
Specific Gravity
Urinalysis
Urine
Urodynamics
Water-Electrolyte Balance
Young Adult

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 -