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

NCT03263975 | Completed

• 1 other identifier: 14-03H
• Study Type: interventional
• Target: 43
• Locations: 0 countries
• Sites: N/A

Brief Summary

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.

Conditions

Dehydration Hypertonic; Isotonic Dehydration

Outcome Measures

Primary Outcomes (1)

• Water and electrolyte retention

  Mass balance measures of total body water and electrolytes

  180 minutes

Secondary Outcomes (1)

• Body water compartment changes

  180 minutes

Study Arms (2)

Exercise heat STress (EHS)

EXPERIMENTAL

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

Lasix (LAS)

EXPERIMENTAL

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

Interventions

Gatorade or Enterade OTHER

Commercially available oral rehydration therapies

Exercise heat STress (EHS); Lasix (LAS)

Eligibility Criteria

• Age: 18 Years - 45 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• 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

You may not qualify if:

• 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.

Sponsors & Collaborators

• United States Army Research Institute of Environmental Medicine: lead

MeSH Terms

Interventions

gatorade

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: FED
• Responsible Party: SPONSOR

Model Details: Between groups design

Study Record Dates

• First Submitted: August 23, 2017
• First Posted: August 28, 2017
• Study Start: October 31, 2014
• Primary Completion: December 8, 2016
• Study Completion: December 1, 2017
• Last Updated: April 22, 2020

Record last verified: 2020-04

Data Sharing

• IPD Sharing: Will not share