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Hydration StatusNCT07298863

The Effect of Hydration Status on Substrate Oxidation at Rest and During Light and Moderate Exercise

A study testing Part 1 - Exercise Trial, Part 1 - Experimental Trial and Part 2 - Oral Glucose Tolerance Test in people with Hydration Status and Substrate Metabolism During Exercise, run by PepsiCo Global R&D at 2 sites in 2 countries.

Active, not recruiting

Under way, not looking for participants. Everyone needed has enrolled. The study is still running.

Official record
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Trial summary

Metabolic flexibility is the ability to properly switch between fat and carbohydrate stores to use for energy under different conditions (rest, feeding, exercise). Impairments in metabolic flexibility, also known as metabolic inflexibility, have been suggested to be an underlying cause of metabolic disease, like type… Read more about this study

Who is it for?
Ages 18 to 35 yearsHealthy volunteers can take part
What is being tested?
Part 1 - Exercise Trial, Part 1 - Experimental Trial and Part 2 - Oral Glucose Tolerance Test
Type of treatment
Pill or oral medicine
Could I receive a placebo?
No, everyone receives an active treatment
How many people
104 participants
Where
2 sitesin 2 countries
Study dates
5 Nov 2025to Sep 2026
Phase
Interventional
Are there results?
Not yet: the study is under way

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

  • Ages 18 to 35 years
  • All sexes
  • Healthy volunteers accepted
  • Adult

Who may be able to join

  • Subject is male or female
  • If female, subject is not pregnant
  • If female, subject has stopped taking birth control medication or removed long-acting reversible contraceptive >6 months at start of the study
  • If female, subject has normal menstrual cycle (25-35 days)
  • If female, subject is currently tracking their menstrual cycle using a smartphone application
  • If female subject is taking iron supplement, they are willing to continue supplementation during entire study
Show all 28Show fewer
  • If female, subject has a smartphone compatible for application to track menstrual cycle
  • Subject is 18-35 years of age, inclusive
  • Subject body mass index (BMI) is between 18.5-25 kg/m2
  • Subject is at least recreationally active (engaged in moderate-intensity, intermittent, or steady-state exercise at least 3 days per week for at least 60 min at a time)
  • Subject is accustomed to cycling for at least 60 min (Part 1 only)
  • 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, laxatives, or weight loss drugs)
  • Subject has no health conditions that would interfere with the study
  • As indicated on the general health questionnaire (GHQ)
  • e.g. cardiovascular, renal, or metabolic diseases
  • Subject is willing to refrain from having MRI scan during study protocol (Part 2 only)
  • Subject is not actively involved in weight loss intervention (dieting and/or anti-obesity medications)
  • Subject is not allergic to adhesives (e.g., medical tape)
  • Subject is not allergic to citrus-raspberry flavor (Part 2 only)
  • 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 (light physical activity only)
  • Subject is willing to be shaved at patch or electrode site, if necessary (Part 1 only)
  • Subject is willing to eat the exact same food prior to each visit to the laboratory
  • Subject is willing to replicate exact diet and physical activity 24 hours before Visits 2/4 and for the 3 days between Visits 3/5 (Part 2 only)
  • Able to speak, write, and read English
  • Provision of written consent to participate

Who cannot join

  • Subject has participated in a clinical trial within the past 30 days
  • Subject has participated in any PepsiCo trial within past 3 months (with the exception of Part 1 participants)
  • 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 allergic to alcohol (alcohol prep pads are used for blood draws).
  • If female, subject is taking birth control medication or has long-acting reversible contraceptive
  • If female, subject is anemic
  • If male, subject is undergoing hormone therapy to alter testosterone levels (injections, transdermal patch, pill, etc.)
  • 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.

Trial locations and contacts

2 sites in 2 countries.

2 sites in 2 countries

United States1 site

  • Gatorade Sports Science Institute

    Valhalla, New York, 10595

Other trials in United States

Canada1 site

  • PeakGenics Innovation InPeakGenics Innovation Incc

    Newcastle, Ontario, L1B0A9

Other trials in Canada

About this study

Metabolic flexibility is the ability to properly switch between fat and carbohydrate stores to use for energy under different conditions (rest, feeding, exercise). Impairments in metabolic flexibility, also known as metabolic inflexibility, have been suggested to be an underlying cause of metabolic disease, like type 2 diabetes. Long-term low fluid intake may increase the risk of type 2 diabetes due to insulin resistance, a form of metabolic inflexibility. Further, low fluid intake has been shown to impair the ability to switch fuel preference during exercise.

While there is some evidence that low fluid intake may lead to impaired metabolic flexibility, more information is needed. Therefore, the purpose of this study is to evaluate the impact of hydration status on substrate preference at rest and during exercise at varying intensities (light and moderate). Further, we will examine whether biological sex and menstrual cycle phase impact hydration and metabolism under these same conditions.

Read the detailed description

This is a 2 part study. Part 1 is a 3-arm intervention to be completed in females during both the follicular and luteal phases for a total of 13 visits including the medical screening. In males, the 3-arm intervention will be completed once for a total of 7 visits including the medical screening.

Part 2 is a randomized, controlled, cross-over study to determine the effects of Euhydration (EUH) vs. Dehydration (DEH) on glycemic control, insulin sensitivity, and metabolic flexibility following an overnight fast and during a 2-hour oral glucose tolerance test (OGTT).

Being tested
Part 1 - Exercise Trial, Part 1 - Experimental Trial, Part 2 - Oral Glucose Tolerance Test
Keywords
hydration, metabolism, fluid retention

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • Part 1 - Exercise TrialOther

    Perform steady-state cycling exercise for approximately 1 hour at 70-80% of maximal heart rate

  • Part 1 - Experimental TrialOther

    24h after exercise trial, following assigned 24h hydration plan, perform indirect calorimetry followed by 30 min of light cycling (~50% VO2 max) then 30 min of moderate-high cycling (~80% VO2 max).

  • Part 2 - Oral Glucose Tolerance TestOther

    a 2-hour oral glucose tolerance test

Study groups in NCT07298863
Study groupRoleWhat they receive
Part 1- Dehydrated control trialOtherFluid restriction during exercise and for remaining 24 hours
Receives: Other: Part 1 - Exercise Trial; Other: Part 1 - Experimental Trial
Part 1 - Euhydrated with waterOtherEuhydrated with water to account for sweat loss and to maintain hydration over 24-hour period
Receives: Other: Part 1 - Exercise Trial; Other: Part 1 - Experimental Trial
Part 1 - Euhydrated with electrolyte beverageExperimentalEuhydrated with electrolyte beverage (220 mg sodium in 20 oz) to account for sweat loss and to maintain hydration over 24-hour period
Receives: Other: Part 1 - Exercise Trial; Other: Part 1 - Experimental Trial
Part 2 - Euhydrated with water and electrolyte beverageExperimentalEuhydrated with water and electrolyte beverage to maintain euhydration status over 3-day study period
Receives: Other: Part 2 - Oral Glucose Tolerance Test
Part 2 - DehydrationOtherfluid restriction during experimental period (3 days),
Receives: Other: Part 2 - Oral Glucose Tolerance Test

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Respiratory Exchange Ratio

    Part 1 only. VCO2 / VO2 measured using indirect calorimetry measured by metabolic cart (Moxus or similar device) while exercising on cycle ergometer.

    Measured: Measured over the course of exercise bouts performed during the exercise and experimental trials. Compared across DEH, EUH-H2O, and EUH-Electrolyte arms.

  2. Blood glucose levels

    Part 2 only. mg/dL

    Measured: baseline and 120-minutes following glucose ingestion for both the dehydration and euhydrated interventions

Secondary outcomes (28)

  1. Body Mass

    Part 1 \& 2. kg

    Measured: Exercise - after bladder void at baseline, post 1st and 2nd 30 min exercise sessions, and post 20 min rest. Experimental -after bladder void at baseline, post 10 min rest, post 1st and 2nd 30 min exercise sessions, and post 20 min rest. OGTT- pre & post

  2. Plasma copeptin concentration

    Part 1 \& 2. pmol/L

    Measured: Exercise trial- Post 10 min rest, pre-exercise bout. Experimental trial- Post 10 min rest, pre indirect calorimetry; post 1st and 2nd 30 min exercise bout; post 20 min rest. OGTT- every 30 min over 2 hour OGTT.

  3. Plasma osmolality

    Part 1 \& 2. mOsm/kg

    Measured: Exercise trial- Post 10 min rest, pre-exercise bout. Experimental trial- Post 10 min rest, pre indirect calorimetry; post 1st and 2nd 30 min exercise bout; post 20 min rest. OGTT- every 30 min over 2 hour OGTT.

  4. Blood glucose

    Part 1. mg/dL

    Measured: At medical screening to determine eligibility. Exercise trial- Post 10 min rest, pre-exercise bout. Experimental trial- Post 10 min rest, pre indirect calorimetry; post 1st and 2nd 30 min exercise bout; post 20 min rest.

  5. Blood lactate

    Part 1 \& 2. mmol/L

    Measured: Exercise trial- Post 10 min rest, pre-exercise bout. Experimental trial- Post 10 min rest, pre indirect calorimetry; post 1st and 2nd 30 min exercise bout; post 20 min rest. OGTT- every 30 min over 2 hour OGTT.

  6. Peripheral blood mononuclear cell (PBMC) mitochondrial function

    Part 1 \& 2. cells/uL

    Measured: Exercise trial- Post 10 min rest, pre-exercise bout. Experimental trial- Post 10 min rest, pre indirect calorimetry; post 1st and 2nd 30 min exercise bout; post 20 min rest. OGTT- every 30 min over 2 hour OGTT.

  7. Urine Specific Gravity

    Part 1 \& 2. au

    Measured: Exercise Trial-baseline, post 1st and 2nd 30 min exercise sessions, and post 20 min rest. Experimental Trial-baseline, post resting metabolism assessment, post 1st and 2nd 30 min exercise sessions, and post 20 min rest. OGTT- pre & post 2 hour OGTT.

  8. Urine Osmolality

    Part 1 \& 2. mOsm/kg

    Measured: Exercise Trial-baseline, post 1st and 2nd 30 min exercise sessions, and post 20 min rest. Experimental Trial-baseline, post resting metabolism assessment, post 1st and 2nd 30 min exercise sessions, and post 20 min rest. OGTT- pre & post 2 hour OGTT

  9. Urine mass

    Part 1 \& 2. g

    Measured: Exercise Trial-baseline, post 1st and 2nd 30 min exercise sessions, and post 20 min rest. Experimental Trial-baseline, post resting metabolism assessment, post 1st and 2nd 30 min exercise sessions, and post 20 min rest. OGTT- pre & post 2 hour OGTT

  10. Urine Color

    Part 1 \& 2. Scale of 1 (most hydrated) to 7 (most dehydrated)

    Measured: Exercise Trial-baseline, post 1st and 2nd 30 min exercise sessions, and post 20 min rest. Experimental Trial-baseline, post resting metabolism assessment, post 1st and 2nd 30 min exercise sessions, and post 20 min rest. OGTT- pre & post 2 hour OGTT.

  11. Fat and Carbohydrate Oxidation

    Part 1 \& 2. resting metabolism measured by Cosmed Quark or similar device. Exercise metabolism measured by Moxus or similar device.

    Measured: Exercise Trial- resting metabolism assessed over 30 min rest period pre-exercise bout and exercise metabolism assessed over final 10 min of 1st and 2nd 30min exercise bout. OGTT- the last 30 min of 2 hour OGTT.

  12. Energy Expenditure

    Part 1 \& 2. kcal-resting metabolism measured by Cosmed Quark or similar device. Exercise metabolism measured by Moxus or similar device.

    Measured: Exercise Trial- resting metabolism assessed over 30 min rest period pre-exercise bout and exercise metabolism assessed over final 10 min of 1st and 2nd 30min exercise bout. OGTT- the last 30 min of 2 hour OGTT.

  13. VO2 peak

    Part 1 only. mL/kg/min measured using indirect calorimetry (Moxus or similar device)

    Measured: Assessed at medical screening during a stress test with a 12-lead EKG on a cycle ergometer.

  14. Fat and fat-free mass

    Part 1 \& Part 2. kg measured using BodPod

    Measured: At medical screening to determine body composition

  15. Fluid Intake

    Part 1 \& Part 2. mL

    Measured: documented by subject on provided log for 24 hours prior to exercise trial, experimental trial, and OGTT. Exercise and Experimental Trial- DEH group restricted from fluid intake. EUH group fluid measured over duration of exercise bout (60 minutes).

  16. Blood Pressure

    Part 1 only. systolic/diastolic (mmHg)

    Measured: Medical Screening to determine eligibility

  17. Heart Rate

    Part 1 only. bpm

    Measured: At medical screening to determine eligibility. Throughout entire duration of each 90-120 min exercise trial. Throughout entire duration of 120-150 min of each experimental trial.

  18. Standardized Exercise Intensity

    Part 1 Only. W

    Measured: Every 10 min throughout entire duration of each 60 min exercise trial to reach 70-80% of VO2 max. Every 10 min throughout entire duration of each 60 min experimental trial to reach 50-80% of VO2 max.

  19. Sweat Rate

    Part 1 only. [Body mass loss (kg) + fluid intake (mL)]/Duration of exercise (hr)

    Measured: Throughout entire duration of 60 min exercise bout of exercise trial. Throughout entire duration of 60 min exercise bout of each experimental trial.

  20. Wearable Sensr Data

    Part 1 only. photoplethysmogram (PPG) waveform data- optical signals obtained from photoplethysmography, which measure blood volume changes in the microvascular bed of tissue.

    Measured: Continuous data collection over 24 hours from start of exercise trial through completion of experimental trial.

  21. Rate of Perceived Exhaustion

    Part 1 Only. Borg scale of rating of perceived exertion. Rated on a 6-20 scale from No exertion at all to maximal exertion.

    Measured: Every 10 min throughout entire duration of each (2x) 30 min exercise bout for each exercise trial. Every 10 min throughout entire duration of each (2x) 30 min exercise bout for each experimental trial.

  22. Menstrual categorization

    Current status (e.g., contraception, regular periods or not, etc.) tracked by physical log or an at-home menstrual cycle monitoring kit (Proov)

    Measured: After medical screening and one month prior to first study session

  23. Adverse Events

    Part 1 \& 2. Documented changes in health and symptoms

    Measured: Through study completion. Part 1 only, an average of 3 weeks for males and 8 weeks for females. Part 2 only, an average of 1 week for males and 4 weeks for females. Part 1 & 2, an average of 4 weeks for males and 12 weeks for females.

  24. RER

    Part 2 only. VCO2 / VO2 measured using indirect calorimetry measured by metabolic cart (Moxus or similar device).

    Measured: 30 min pre-2 hour OGTT.

  25. Diet Log

    Part 1 \& 2.

    Measured: documented by subject on provided log for 24 hours prior to exercise trial, experimental trial, and OGTT to confirm similar diets across trial days.

  26. AUC during OGTT

    Part 2 only. Area under the curve

    Measured: Across 2 hour OGTT at 30 min increments.

  27. Plasma insulin concentration

    Part 2 only. insulin units

    Measured: Across 2 hour OGTT at 30 min increments.

  28. Continuous Glucose Monitor (CGM) Outputs

    Part 2 only. time in range, time above range, time below range

    Measured: Throughout study participation, an average of 1 week for males and 4 weeks for females.

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted23 Dec 2025
  2. Study start5 Nov 2025
  3. Primary completionSep 2026 (estimated)
  4. Study completionSep 2026 (estimated)

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Interventional
Phase
Phase N/A
Primary purpose
Other
Allocation
Randomised
Intervention model
Crossover
Model description
Randomized, controlled, cross-over study (counterbalanced).
Masking
None (open label)
Enrolment
104 participants (estimated)
IDs, dates and publications
ClinicalTrials.gov ID
NCT07298863
Sponsor's protocol ID
PEP-2507
Status last verified
Aug 2026
First submitted
24 Nov 2025
Last updated
27 Aug 2026
Results posted
No
Data monitoring committee
No
FDA-regulated drug
No
FDA-regulated device
No
Individual data sharing
No

Questions about this trial

What is this clinical trial studying?

A study testing Part 1 - Exercise Trial, Part 1 - Experimental Trial and Part 2 - Oral Glucose Tolerance Test in people with Hydration Status and Substrate Metabolism During Exercise, run by PepsiCo Global R&D at 2 sites in 2 countries.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 28 inclusion and 8 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: under way, not looking for participants, as of the sponsor's last update on 27 Aug 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 2 sites in United States, Canada. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

Are results available for this study?

This study is still under way. Results are not available in the source record yet.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Respiratory Exchange Ratio (time frame: Measured over the course of exercise bouts performed during the exercise and experimental trials. Compared across DEH, EUH-H2O, and EUH-Electrolyte arms.). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT07298863.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 27 Aug 2026.

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