Effects of Dehydration on Neuromuscular Performance and Sympathetic Control of Cardiovascular Function

April 20, 2020 updated by: United States Army Research Institute of Environmental Medicine

The mechanism(s) by which dehydration (both intra- and extracellular) impairs performance are still poorly described. A loss of volume results in increased occurrence of orthostatic intolerance, including dizziness, fatigue, headaches and related symptoms with upright posture. Any of these symptoms can contribute to decreased performance in maneuvers performed in the upright posture, which includes many military tasks. Thus, loss of volume challenges the cardiovascular and blood pressure responses to systemic whole body endurance exercise, while osmolality is the stimulus for intracellular dehydration that may impair local muscle force production by impairing contractile function, neural signaling, or both. In this study, we will compare how both types of dehydration affect MSNA and CAC.

The results of this study will provide mechanistic insight for how dehydration (intra- or extracellular) impairs systemic whole body and local small muscle performance in vivo. This Basic Science study seeks to understand how volume and osmolality impact MSNA and CAC as a basis for improving potential countermeasures, such as a more optimally formulated rehydration beverage. Therefore, this study directly complements Task Area T10 (Hot Weather Operations and Hydration: Injury and Performance Optimization) and impacts virtually all 14 Military Operational Medicine Research Program Drivers.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

Study Objectives and Hypotheses

Primary Objective

The primary objectives of this study are to understand the in vivo effects of dehydration on:

  1. Sympathetic neural control of cardiovascular function (MSNA), and
  2. Neuromuscular function (CAC) via the IT Test

The primary hypotheses of this study are:

  1. Baseline MSNA, and MSNA responses to tilt, will be higher in response to extracellular dehydration due to larger intravascular volume losses and greater baroreceptor unloading.
  2. Neuromuscular function (CAC) via the IT Test will a) be more impaired by intracellular dehydration (cell stress) and b) CAC will show a greater performance reduction than CAR because it reduces the emphasis placed on the voluntary portion of performance (i.e., MVC).

Ancillary Questions/Sub Studies

  1. The collection of blood and urine before and after exercise-heat stress and dehydration provides an opportunity to measure and characterize cytokine and intestinal barrier integrity marker (I-FAB, claudin-3) responses (blood) and renal stress biomarkers (urine) in humans. This descriptive research 'sub-study' directly complements Task Area T10 (Hot Weather Operations and Hydration: Injury and Performance Optimization) near and mid-term research goals of identifying biomarkers of heat stress for protection against heat injury. There are no hypotheses associated with this sub-study.
  2. The study of dehydration requires rehydration for recovery. Rehydration provides an opportunity for a novel comparison of renal water retention (urine volume) when consuming equal volumes of two different commercial beverages (Gatorade® or Enterade-S®). Unlike Gatorade®, which is a carbohydrate-based beverage containing electrolytes, Enterade-S® is an amino acid-based beverage containing electrolytes. We hypothesize that the unique formulation of Enterade-S® will improve the rate of fluid absorption and fluid retention compared to Gatorade® in both intracellular and extracellular dehydration trials.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
43

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

14 years to 41 years (Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • Male or female, age 18-45
  • In good health as determined by OMSO General Medical Clearance
  • Passed his/her most recent Army Physical Fitness Test (APFT) (military volunteers only) or exercise at least 2 times per week (civilian volunteers)
  • Ability to comprehend and willingness to sign informed consent

Exclusion Criteria:

  • Females who are pregnant or planning to become pregnant during the study
  • Taking prescription or over the counter medication, other than a contraceptive (unless approved by OMSO and PI)
  • Physical problems/injuries associated with walking or cycling
  • Allergy to sulfa drugs (Lasix™ or sulfonamide antibiotics such as Septra™)
  • Allergy to skin adhesive
  • Hemoglobinopathy (sickle cell trait)
  • Heart, lung, kidney, muscle, or nerve disorder(s)
  • History of heat or orthostatic intolerance
  • Diagnosed and/or treated for fluid/electrolyte imbalance within the last 30 days
  • Presence of metal implants/electronic medical devices in lower extremities
  • Current or previous (within the past 5 years) diagnosis of any autonomic disorder, including idiopathic orthostatic intolerance, orthostatic hypotension, postural tachycardia syndrome (POTS), or neurocardiogenic syncope (MSNA group only)
  • Tobacco/nicotine use (MSNA group only)
  • Significant muscle, joint, or bone injury affecting the legs within the last 6 months (CAC group only)
  • Difficulty swallowing large pills
  • History of obstructive disease of the gastrointestinal tract including (but not limited to) diverticulosis, diverticulitis and inflammatory bowel disease, peptic ulcer disease, Crohn's disease, ulcerative colitis; or previous gastrointestinal surgery.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Exercise heat STress (EHS)
EHS - dehydration produced by sweating and fluid restriction; primary loss of body water accompanied by small loss of electrolytes (hypertonicity). Interventions include rehydration with Gatorade or Enterade oral rehydration therapies.
Other: Gatorade or Enterade
Commercially available oral rehydration therapies
Experimental: Lasix (LAS)
LAS - dehydration produced by Lasix (diuretic, 80 mg oral dose) administration to produce losses of body water accompanied by large losses of electrolytes (isotoncity). Interventions include rehydration with Gatorade or Enterade oral rehydration therapies.
Other: Gatorade or Enterade
Commercially available oral rehydration therapies

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Water and electrolyte retention
Time Frame: 180 minutes
Mass balance measures of total body water and electrolytes
180 minutes

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Body water compartment changes
Time Frame: 180 minutes
Osmometric measurements and calculations of body fluid spaces
180 minutes

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
United States Army Research Institute of Environmental Medicine

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
October 31, 2014

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
December 8, 2016

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
December 1, 2017

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
August 23, 2017

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
August 23, 2017

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
August 28, 2017

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
April 22, 2020

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
April 20, 2020

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
April 1, 2020

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 14-03H

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

No

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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