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Human Hydration Status Monitoring

Information source: United States Army Research Institute of Environmental Medicine
ClinicalTrials.gov processed this data on August 20, 2015
Link to the current ClinicalTrials.gov record.

Condition(s) targeted: Dehydration

Intervention: Dehydration (Procedure)

Phase: Phase 2

Status: Completed

Sponsored by: United States Army Research Institute of Environmental Medicine

Official(s) and/or principal investigator(s):
Samuel N Cheuvront, PhD, Principal Investigator, Affiliation: United States Army Research Institute of Environmental Medicine


The sports medicine literature provides a consensus on what threshold values constitute euhydration (normal body water) using a variety of hydration assessment markers (e. g., blood, urine). The investigators add to this literature by providing decision levels for multiple body fluids which can be used as starting points for diagnosing and treating dehydration. At present, plasma osmolality (Posm) provides the best potential measure for static dehydration assessment (spot measure), while dynamic dehydration assessment (serial monitoring) is best accomplished using change values for Posm, urine specific gravity, or body mass (weight). These findings should be considered useful for clinical, military, and sports medicine communities.

Clinical Details

Official title: Human Hydration Status Monitoring: Phase I

Study design: Allocation: Randomized, Endpoint Classification: Efficacy Study, Intervention Model: Crossover Assignment, Masking: Single Blind (Outcomes Assessor), Primary Purpose: Diagnostic

Primary outcome: Evidence of clinical dehydration

Detailed description: Well-recognized markers for static (one time) or dynamic (monitoring over time) dehydration assessment have not been rigorously tested for their usefulness in clinical, military, and sports medicine communities. This study evaluated the components of biological variation and accuracy of potential markers in plasma, urine, saliva, and body mass, for static and dynamic dehydration assessment. Design: Eighteen healthy volunteers (13M, 5F) were studied while carefully controlling hydration and numerous pre-analytical factors. Biological variation was determined over three consecutive days using published methods. Atypical values based on statistical deviations from a homeostatic set-point were examined. Measured deviations in body fluid were produced using a separate, prospective dehydration experiment and evaluated by ROC analysis to quantify diagnostic accuracy. All dehydration markers displayed substantial individuality and half displayed marked heterogeneity of intra-individual variation. Decision levels for all dehydration markers were within one standard deviation of the ROC criterion values and most were nearly

identical to the prospective group means after dehydrating volunteers by 1. 8 - 7. 0% of body

mass. However, only plasma osmolality (Posm) showed statistical promise for use in static dehydration assessment. A 301 ± 5 mmol/kg diagnostic decision level is proposed. Reference change values (RCV) of 9 mmol/kg (Posm), 0. 010 (urine specific gravity, Usg), and 2. 5% change in body mass (Bm) were also statistically valid for dynamic dehydration assessment at the 95% probability level. Posm is the only useful marker for static dehydration assessment. Posm, Usg, and Bm are valid markers in the setting of dynamic dehydration assessment.


Minimum age: 18 Years. Maximum age: 39 Years. Gender(s): Both.


Inclusion Criteria:

- You are a member of the U. S. Army between 18-39 years of age

- You have passed the APFT within the previous 12 months

- You have completed and passed a recent medical physical exam

- You are willing to discuss with OMSO and the Principle Investigator (PI) all

medications and supplements you are taking and you are willing to stop taking any supplements not approved by OMSO and the PI. Exclusion Criteria:

- You have any physical problems that would make exercise difficult

- You have ever had a heat injury or have a history of having trouble in the heat

- You have an allergy to sulfa drugs

- You have been treated for dry eyes

- You are pregnant, planning on becoming pregnant during the study, or are presently


Locations and Contacts

USARIEM, Natick, Massachusetts 01760-5007, United States
Additional Information

Starting date: January 2009
Last updated: February 29, 2012

Page last updated: August 20, 2015

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