Human Hydration Status Monitoring

Study Description

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Brief Summary:

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 or disease	Intervention/treatment	Phase
Dehydration	Procedure: Dehydration	Phase 2

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.

Study Design

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Study Type :	Interventional (Clinical Trial)
Actual Enrollment :	31 participants
Allocation:	Randomized
Intervention Model:	Crossover Assignment
Masking:	Single (Outcomes Assessor)
Primary Purpose:	Diagnostic
Official Title:	Human Hydration Status Monitoring: Phase I
Study Start Date :	January 2009
Actual Primary Completion Date :	February 2011
Actual Study Completion Date :	March 2011

Arms and Interventions

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Study Description Study Design Arms and Interventions Outcome Measures Eligibility Criteria Contacts and Locations More Information

Arm	Intervention/treatment
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

Outcome Measures

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Primary Outcome Measures :

1. 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.

Eligibility Criteria

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

Criteria

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

Contacts and Locations

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Study Description Study Design Arms and Interventions Outcome Measures Eligibility Criteria Contacts and Locations More Information

Locations

United States, Massachusetts
USARIEM
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

Investigators

Principal Investigator:	Samuel N Cheuvront, PhD	United States Army Research Institute of Environmental Medicine

More Information

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Study Description Study Design Arms and Interventions Outcome Measures Eligibility Criteria Contacts and Locations More Information

Responsible Party:	Samuel N. Cheuvront, Principal Investigator, United States Army Research Institute of Environmental Medicine
ClinicalTrials.gov Identifier:	NCT01124903 History of Changes
Other Study ID Numbers:	H08-12
First Posted:	May 17, 2010
Last Update Posted:	March 1, 2012
Last Verified:	February 2012

Keywords provided by Samuel N. Cheuvront, United States Army Research Institute of Environmental Medicine:

dehydration; hypohydration; diagnostic accuracy; biological variation; hydration assessment	body mass; osmolality; plasma; saliva; urine

Additional relevant MeSH terms:

Dehydration; Water-Electrolyte Imbalance; Metabolic Diseases; Pathologic Processes