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Human Hydration Status Monitoring

This study has been completed.
ChromoLogic, LLC
Intelligent Automation, Inc.
Gaia Medical Institute
Information provided by (Responsible Party):
Samuel N. Cheuvront, United States Army Research Institute of Environmental Medicine Identifier:
First received: May 14, 2010
Last updated: February 29, 2012
Last verified: February 2012
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.

Condition Intervention Phase
Procedure: Dehydration
Phase 2

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Single Blind (Outcomes Assessor)
Primary Purpose: Diagnostic
Official Title: Human Hydration Status Monitoring: Phase I

Resource links provided by NLM:

Further study details as provided by Samuel N. Cheuvront, United States Army Research Institute of Environmental Medicine:

Primary Outcome Measures:
  • Evidence of clinical dehydration [ Time Frame: 24 hours ]
    Dehydration was carefully imposed in healthy human subjects. The diagnostic usefulness of multiple classic and novel dehydration assessment measures was made.

Enrollment: 31
Study Start Date: January 2009
Study Completion Date: March 2011
Primary Completion Date: February 2011 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: Dehydration
Multiple measures of hydration status were made when subjects were normally hydrated (euhydrated) and when dehydrated. The diagnostic usefulness of the measures was determined.
Procedure: Dehydration
Subjects were dehydrated by 2 - 7% of body mass over 3-5 hours using exercise-heat stress and fluid restriction.
Other Name: Hypohydration

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.


Ages Eligible for Study:   18 Years to 39 Years   (Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes

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 lactating
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Please refer to this study by its identifier: NCT01124903

United States, Massachusetts
Natick, Massachusetts, United States, 01760-5007
Sponsors and Collaborators
United States Army Research Institute of Environmental Medicine
ChromoLogic, LLC
Intelligent Automation, Inc.
Gaia Medical Institute
Principal Investigator: Samuel N Cheuvront, PhD United States Army Research Institute of Environmental Medicine
  More Information

Responsible Party: Samuel N. Cheuvront, Principal Investigator, United States Army Research Institute of Environmental Medicine Identifier: NCT01124903     History of Changes
Other Study ID Numbers: H08-12
Study First Received: May 14, 2010
Last Updated: February 29, 2012

Keywords provided by Samuel N. Cheuvront, United States Army Research Institute of Environmental Medicine:
diagnostic accuracy
biological variation
hydration assessment
body mass

Additional relevant MeSH terms:
Water-Electrolyte Imbalance
Metabolic Diseases
Pathologic Processes processed this record on May 25, 2017