Human Hydration Status Monitoring

Human Hydration Status Monitoring: Phase I

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.

Study Overview

• Status: Completed
• Conditions: Dehydration
• Intervention / Treatment: Procedure: 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.

• Study Type: Interventional
• Enrollment (Actual): 31
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Massachusetts
    • Natick, Massachusetts, United States, 01760-5007
      • USARIEM

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 39 years (Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

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

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: Single

Number of Arms

1

Arms and Interventions

Participant Group / 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 Names: Hypohydration

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Evidence of clinical dehydration	Dehydration was carefully imposed in healthy human subjects. The diagnostic usefulness of multiple classic and novel dehydration assessment measures was made.	24 hours

Collaborators and Investigators

• Sponsor: United States Army Research Institute of Environmental Medicine
• Collaborators: Intelligent Automation, Inc.; ChromoLogic, LLC; Gaia Medical Institute
• Investigators: Principal Investigator: Samuel N Cheuvront, PhD, United States Army Research Institute of Environmental Medicine

Study record dates

Study Major Dates

• Study Start: January 1, 2009
• Primary Completion (Actual): February 1, 2011
• Study Completion (Actual): March 1, 2011

Study Registration Dates

• First Submitted: May 14, 2010
• First Submitted That Met QC Criteria: May 14, 2010
• First Posted (Estimate): May 17, 2010

Study Record Updates

• Last Update Posted (Actual): April 22, 2020
• Last Update Submitted That Met QC Criteria: April 20, 2020
• Last Verified: April 1, 2020

More Information

Terms related to this study

• Keywords: diagnostic accuracy; urine; saliva; dehydration; plasma; body mass; hydration assessment; hypohydration; biological variation; osmolality
• Additional Relevant MeSH Terms: Pathologic Processes; Metabolic Diseases; Water-Electrolyte Imbalance; Dehydration
• Other Study ID Numbers: H08-12