Document Detail

Human hydration indices: acute and longitudinal reference values.
MedLine Citation:
PMID:  20479488     Owner:  NLM     Status:  MEDLINE    
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.
Lawrence E Armstrong; Amy C Pumerantz; Kelly A Fiala; Melissa W Roti; Stavros A Kavouras; Douglas J Casa; Carl M Maresh
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  International journal of sport nutrition and exercise metabolism     Volume:  20     ISSN:  1526-484X     ISO Abbreviation:  Int J Sport Nutr Exerc Metab     Publication Date:  2010 Apr 
Date Detail:
Created Date:  2010-05-18     Completed Date:  2010-06-22     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  100939812     Medline TA:  Int J Sport Nutr Exerc Metab     Country:  United States    
Other Details:
Languages:  eng     Pagination:  145-53     Citation Subset:  IM    
Human Performance Laboratory, University of Connecticut, Storrs, CT, USA.
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MeSH Terms
Body Water / chemistry,  metabolism*
Circadian Rhythm / physiology*
Dehydration / diagnosis,  urine
Hydrogen-Ion Concentration
Osmolar Concentration
Reference Values
Specific Gravity
Urine / chemistry*
Urodynamics / physiology
Water-Electrolyte Balance / physiology*
Young Adult

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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