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

NCT ID: NCT07298863

Last Updated: 2025-12-23

Study Results

Results pending

The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.

Basic Information

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Recruitment Status

RECRUITING

Clinical Phase

NA

Total Enrollment

74 participants

Study Classification

INTERVENTIONAL

Study Start Date

2025-11-05

Study Completion Date

2026-04-30

Brief Summary

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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.

Detailed Description

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The 3-arm intervention will 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.

Conditions

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Hydration Status Substrate Metabolism During Exercise

Keywords

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hydration metabolism fluid retention

Study Design

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Allocation Method

RANDOMIZED

Intervention Model

CROSSOVER

Randomized, controlled, cross-over study (counterbalanced).
Primary Study Purpose

OTHER

Blinding Strategy

NONE

Study Groups

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Euhydrated with electrolyte beverage

Euhydrated with electrolyte beverage (220 mg sodium in 20 oz) to account for sweat loss and to maintain hydration over 24-hour period

Group Type EXPERIMENTAL

Exercise Trial

Intervention Type OTHER

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

Experimental Trial

Intervention Type OTHER

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).

Euhydrated with water

Euhydrated with water to account for sweat loss and to maintain hydration over 24-hour period

Group Type OTHER

Exercise Trial

Intervention Type OTHER

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

Experimental Trial

Intervention Type OTHER

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).

Dehydrated control trial

Fluid restriction during exercise and for remaining 24 hours

Group Type OTHER

Exercise Trial

Intervention Type OTHER

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

Experimental Trial

Intervention Type OTHER

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).

Interventions

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Exercise Trial

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

Intervention Type OTHER

Experimental Trial

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).

Intervention Type OTHER

Eligibility Criteria

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Inclusion Criteria

* Subject is male or female
* If female, subject is not pregnant (based on self-report)
* 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 (21-35 days)
* If female, subject is willing to track their menstrual cycle
* If female, subject has a smartphone compatible for application to track menstrual cycle (female only) and/or wearable data (females and males)
* 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
* 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 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 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
* Subject is willing to eat the exact same food the day prior to each visit to the laboratory
* Able to speak, write, and read English
* 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 36 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 allergic to alcohol (alcohol pre pads are used for blood draws
* If female, subject is taking birth control medication or has long-acting reversible contraceptive
* 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.
Minimum Eligible Age

18 Years

Maximum Eligible Age

35 Years

Eligible Sex

ALL

Accepts Healthy Volunteers

Yes

Sponsors

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University of Ontario Institute of Technology

OTHER

Sponsor Role collaborator

PepsiCo Global R&D

INDUSTRY

Sponsor Role lead

Responsible Party

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Responsibility Role SPONSOR

Locations

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Gatorade Sports Science Institute

Valhalla, New York, United States

Site Status RECRUITING

University Of Ontario Institute Of Technology

Oshawa, Ontario, Canada

Site Status RECRUITING

Countries

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United States Canada

Central Contacts

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Matt Hinkley

Role: CONTACT

Phone: 570-574-1858

Email: [email protected]

Facility Contacts

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Matt Hinkley

Role: primary

Heather Sprenger

Role: primary

Other Identifiers

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PEP-2507

Identifier Type: -

Identifier Source: org_study_id