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

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.

NCT Number	NCT07298863
Lead Sponsor	PepsiCo Global R&D
Conditions	Hydration Status, Substrate Metabolism During Exercise
Enrollment	74 participants
Start Date	2025-11-05
Primary Completion	2026-04-01 (estimated)
Study Completion	2026-04-30 (estimated)
Updated on ClinicalTrials.gov	2026-03-03