Effects of Beverage Volume, Glycerol Concentration, and Sodium Concentration on Fluid Balance in Healthy Euhydrated Men and Women at Rest

The presence of certain ingredients such as sodium and glycerol can facilitate retention of the fluid consumed via renal water reabsorption. To maintain overall whole-body fluid balance, it is important that ingested fluid is retained in the body instead of losing it through urination.

The purpose of this study is to determine the effect of sodium and glycerol concentrations at various fluid intake volumes on fluid balance in healthy, euhydrated men and women.

Study Overview

• Status: Recruiting
• Conditions: Fluid Balance
• Intervention / Treatment: Other: Placebo beverage, kiwi-strawberry flavor; Other: Electrolyte solution without glycerol beverage 1; Other: Electrolyte solution without glycerol beverage 2; Other: Electrolyte solution without glycerol beverage 3; Other: Electrolyte solution with glycerol beverage 1; Other: Electrolyte solution with glycerol beverage 2; Other: Electrolyte solution with glycerol beverage 3; Other: Base with glycerol, no electrolytes beverage 1; Other: Base with glycerol, no electrolytes beverage 2; Other: Base with glycerol, no electrolytes beverage 3

• Study Type: Interventional
• Enrollment (Estimated): 80
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Lindsay Baker, PhD; Phone Number: 800.884.2867; Email: Lindsay.Baker@pepsico.com

Study Locations

• United States
  • Florida
    • Bradenton, Florida, United States, 34210
      • Recruiting
      • IMG Academy/GSSI Bradenton Gatorade Sports Science Institute
      • Contact: Kris Osterberg, PhD; Phone Number: 941-201-3820; Email: kris.osterberg@pepsico.com
    • Saint Petersburg, Florida, United States, 33705
      • Recruiting
      • GCP Research
      • Contact: Madelaine Perez; Phone Number: 727.520.1427; Email: mperez@researchgcp.com
      • Contact: Jessica Cruz, RN; Phone Number: 727.520.1427; Email: jcruz@researchgcp.com
  • New York
    • Valhalla, New York, United States, 10595
      • Recruiting
      • Gatorade Sports Science Institute
      • Contact: Lindsay Baker, PhD; Phone Number: 814-883-9454

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Subject is male or female
• If female, subject is not pregnant
• Subject is 18-50 years of age, inclusive
• Subject is at least recreationally active (engaged in light to moderate-intensity, intermittent, or steady-state exercise at least 3 days per week for at least 30 min at a time)
• Subject does not smoke (or has quit for at least 6 months)
• Subject is not taking medication that may interfere with the study (e.g., diuretics)
• Subject has no health conditions that would interfere with the study (e.g. cardiovascular, renal, or metabolic diseases)
• Subject is willing to avoid alcohol consumption 24 hours prior to visit(s)
• Subject is willing to fast overnight (~8-12 hours)
• Subject is willing to refrain from vigorous exercise for 24 hours
• Subject is willing to eat the exact same food the day prior to each visit to the laboratory
• Provision of written consent to participate

Exclusion Criteria:

• Subject has participated in a clinical trial within the past 30 days
• Subject has participated in any PepsiCo trial within past 6 months
• Subject has a condition or is taking medication that the investigator believes would interfere with his/her ability to provide informed consent, comply with the study protocol, which might confound the interpretation of the study results, or put the person at undue risk
• Subject is employed by, or has a parent, guardian, or other immediate family member employed by a company that manufactures any products that compete with any Gatorade product. If subject is unsure if a company would be considered a competitor to Gatorade, they will be asked to please let the study investigator know the name of the other company and the nature of their relationship to that company before they sign the informed consent.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Other
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Quadruple

Number of Arms

10

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Placebo Comparator: Placebo beverage; Base beverage, no electrolytes, no glycerol	Other: Placebo beverage, kiwi-strawberry flavor; 9.3.oz 3 times for a total of 28 oz over a 35 min period followed by 25 min rest until Time 0 post-dose
Experimental: Electrolyte solution without glycerol beverage 1; Higher electrolytes lower volume	Other: Electrolyte solution without glycerol beverage 1; 4 oz 3 times for a total of 12 oz over a 35 min period followed by 25 min rest until Time 0 post-dose. Beverage matched to placebo for color and flavor.
Experimental: Electrolyte solution without glycerol beverage 2; Lower electrolytes mid-volume	Other: Electrolyte solution without glycerol beverage 2; 6.7 oz 3 times for a total of 20 oz over a 35 min period followed by 25 min rest until Time 0 post-dose. Beverage matched to placebo for color and flavor.
Experimental: Electrolyte solution without glycerol beverage 3; Higher electrolytes higher volume	Other: Electrolyte solution without glycerol beverage 3; 9.3.oz 3 times for a total of 28 oz over a 35 min period followed by 25 min rest until Time 0 post-dose. Beverage matched to placebo for color and flavor.
Experimental: Electrolyte solution with glycerol beverage 1; Lower electrolytes, lower glycerol, lower volume	Other: Electrolyte solution with glycerol beverage 1; 4 oz 3 times for a total of 12 oz over a 35 min period followed by 25 min rest until Time 0 post-dose. Beverage matched to placebo for color and flavor.
Experimental: Electrolyte solution with glycerol beverage 2; Higher electrolytes, higher glycerol, lower volume	Other: Electrolyte solution with glycerol beverage 2; 4 oz 3 times for a total of 12 oz over a 35 min period followed by 25 min rest until Time 0 post-dose. Beverage matched to placebo for color and flavor.
Experimental: Electrolyte solution with glycerol beverage 3; Higher electrolytes, higher glycerol, higher volume	Other: Electrolyte solution with glycerol beverage 3; 9.3.oz 3 times for a total of 28 oz over a 35 min period followed by 25 min rest until Time 0 post-dose. Beverage matched to placebo for color and flavor.
Experimental: Base with glycerol beverage 1; No electrolytes, higher glycerol, lower volume	Other: Base with glycerol, no electrolytes beverage 1; 4 oz 3 times for a total of 12 oz over a 35 min period followed by 25 min rest until Time 0 post-dose. Beverage matched to placebo for color and flavor.
Experimental: Base with glycerol beverage 2; No electrolytes, lower glycerol, mid-volume	Other: Base with glycerol, no electrolytes beverage 2; 6.7 oz 3 times for a total of 20 oz over a 35 min period followed by 25 min rest until Time 0 post-dose. Beverage matched to placebo for color and flavor.
Experimental: Base with glycerol beverage 3; No electrolytes, higher glycerol, higher volume	Other: Base with glycerol, no electrolytes beverage 3; 9.3.oz 3 times for a total of 28 oz over a 35 min period followed by 25 min rest until Time 0 post-dose. Beverage matched to placebo for color and flavor.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Fluid balance	Calculated as change in body mass kg and %	Change from baseline (pre-beverage) to post-beverage Time 30, 60, 90,120, 150,180 and 210 minutes

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Urine mass	(g)	Change from baseline (pre-beverage) to post-beverage Time 30, 60, 90,120, 150,180 and 210 minutes
Urine specific gravity	(au)	Change from baseline (pre-beverage) to post-beverage Time 30, 60, 90,120, 150,180 and 210 minutes
Urine osmolality	(mosmol/kg)	Change from baseline (pre-beverage) to post-beverage Time 30, 60, 90,120, 150,180 and 210 minutes
Whole blood hemoglobin concentration	(g/dl)	Change from baseline (pre-beverage) to post-beverage Time 30, 90,150 and 210 minutes
Serum sodium concentration	(mmol/L)	Change from baseline (pre-beverage) to post-beverage Time 30, 90,150 and 210 minutes
Serum potassium concentration	(mmol/L)	Change from baseline (pre-beverage) to post-beverage Time 30, 90,150 and 210 minutes
Serum chloride concentration (mmol/L)	(mmol/L)	Change from baseline (pre-beverage) to post-beverage Time 30, 90,150 and 210 minutes
Serum glucose concentration	(mg/dl)	Change from baseline (pre-beverage) to post-beverage Time 30, 90,150 and 210 minutes
Serum glycerol concentration	(mmol/L)	Change from baseline (pre-beverage) to post-beverage Time 30, 90,150 and 210 minutes
Serum copeptin concentration	(pmol/L)	Change from baseline (pre-beverage) to post-beverage Time 30, 90,150 and 210 minutes
Serum osmolality	(mosmol/kg)	Change from baseline (pre-beverage) to post-beverage Time 30, 90,150 and 210 minutes
Blood pressure	(systolic/diastolic) (mmHg)	Change from baseline (pre-beverage) to post-beverage Time 30, 60, 90,120, 150,180 and 210 minutes
Heart rate	(bpm)	Change from baseline (pre-beverage) to post-beverage Time 30, 60, 90,120, 150,180 and 210 minutes
Subjective measures of gastrointestinal discomfort and headache (VAS)	Rated on a 100 point scale from none to severe for headache, lightheaded, stomach upset, nausea, burping, stomach bloating, abdominal discomfort, stomach fullness, vomiting, diarrhea).	Change from baseline (pre-beverage) to post-beverage Time 30, 60, 90,120, 150,180 and 210 minutes
Menstrual categorization	Current status (e.g., contraception, regular periods or not, etc.)	Screening visit
Adverse Events	Documented changes in health and symptoms	From Screening (Visit 1) through the fifth and final beverage testing day (Visit 6)
Whole blood hematocrit	(%)	Change from baseline (pre-beverage) to post-beverage Time 30, 90,150 and 210 minutes

Collaborators and Investigators

• Sponsor: PepsiCo Global R&D
• Investigators: Principal Investigator: Lindsay Baker, PhD, PepsiCo R&D/Gatorade and Sports Science Institute

Study record dates

Study Major Dates

• Study Start (Actual): April 9, 2025
• Primary Completion (Estimated): December 15, 2025
• Study Completion (Estimated): December 15, 2025

Study Registration Dates

• First Submitted: February 19, 2025
• First Submitted That Met QC Criteria: February 28, 2025
• First Posted (Actual): March 3, 2025

Study Record Updates

• Last Update Posted (Actual): July 17, 2025
• Last Update Submitted That Met QC Criteria: July 14, 2025
• Last Verified: July 1, 2025

More Information

Terms related to this study

• Keywords: beverage; electrolytes; hydration; glycerol
• Additional Relevant MeSH Terms: Physiological Effects of Drugs; Protective Agents; Cryoprotective Agents; Pharmaceutical Solutions; Glycerol
• Other Study ID Numbers: PEP-2420

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