Effect of Glycerol Hyperhydration on Running Economy of Long-distance Runners

NCT06818253 | Completed

• 1 other identifier: IICDEM-ID-001-2022
• Study Type: interventional
• Target: 30
• Locations: 1 country
• Sites: 1

Brief Summary

The aim of this study was to evaluate the effects of hyperhydration with glycerol on running economy (RE) in trained runners. The main questions sought to be answered are:

1. 1.Does hyperhydration with glycerol improve running economy?
2. 2.Are there beneficial effects on physical performance?

Conditions

Running; Physical Conditioning, Human

Keywords

Glycerol; athletic performance; sports nutritional sciences; thermoregulation; running

Outcome Measures

Primary Outcomes (2)

• Maximal oxygen consumption (VO₂peak) (ml/kg/min)

  Session 1: VO2peak measurements through an incremental treadmill test with 2 km/h speed increments every 3 minutes, maintaining a constant 1% incline. The test started at 6 km/h for all participants and continued until volitional exhaustion

  In the first evaluation session to be held in the first week of a total of 3 weeks of study duration

• Running economy (CE)

  Test under Hydration Restriction (No-GLY): As a mandatory requirement, participants reported to the laboratory in a euhydrated state (USG: 1.018-1.024) prior to the start of the test, following the criteria outlined in previous research \[31\]. They ran for 15 minutes on a treadmill at a speed equivalent to 65%-70% of their VO2peak from the first session. During the test, running economy variables such as the caloric cost unit (CCU), oxygen cost unit (OCU), body temperature (BT), rating of perceived exertion (RPE) via the Borg scale, and hydration status were measured. Running Economy Calculation: i) The caloric cost unit (CCU) was calculated via the following equation \[25\]: CCU =((VO2 x δ x 1000)/(V x MC)) x 100 where VO2 is the oxygen consumption rate (L/min); δ is the kcal/L of oxygen based on the respiratory exchange ratio (RER); V is the speed (m/min); and MC is the body mass (kg).

  In the first evaluation session to be held in the first week of a total of 3 weeks of study duration

Secondary Outcomes (3)

• Body temperature

  Body temperature was measured during sessions 2 (No Gly) and 3 (Gly) at the following times: at minute 0 (prior to the start of each test) and at minutes 5, 10 and 15 during a treadmill test.

• Perception of exertion

  It was applied during the evaluation of the stress tests to determine the Vo2peak and Running Economy.

• Sweating rate.

  In sessions 1 and 2, urine specific gravity (USG) was assessed, which was one of the key criteria for determining whether subjects could continue in the study without being eliminated.

Study Arms (1)

Arm glycerol supplementation

EXPERIMENTAL

This arm participated in a crossover design allowed minimizing interindividual variability by using each participant as their own control, evaluating the conditions of (1) hyperhydration with glycerol and (2) water restriction. The main variables evaluated were maximal oxygen consumption (VO₂max), running economy (CE), calculated using the oxygen cost unit (OCU) and caloric cost unit (CCU), as well as body temperature, perception of exertion and sweating rate.

Dietary Supplement: The Effect of Glycerol Supplements

Interventions

The Effect of Glycerol Supplements DIETARY_SUPPLEMENT

The main factor that distinguishes this intervention is first of all the dosage of the dietary supplement and the effects on the variables to be analyzed related to physical performance.

Arm glycerol supplementation

Eligibility Criteria

• Age: 18 Years - 35 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• Competitive runners with a minimum record of 4.2 min/km.
• Age between 18 and 35 years old
• Apparently healthy athletes
• Signature of informed consent form

You may not qualify if:

• Presence of comorbidities that could alter the study variables (such as arterial hypertension, hyperthyroidism or heart disease).
• Consumption of medications or stimulants (such as caffeine or diuretics) 48 hours before the tests.
• Pregnancy.

Sponsors & Collaborators

• Iberoamerican Institute of Sports Science and Human Movement: lead
• University of Guadalajara: collaborator

Study Sites (1)

Universidad de Guadalajara, Centro Universitario de Tonalá

Guadalajara, Jalisco, 45425, Mexico

Location

Related Publications (2)

• Jolicoeur Desroches A, Naulleau C, Deshayes TA, Parent-Roberge H, Pancrate T, Goulet EDB. Effect of Glycerol-Induced Hyperhydration on a 5-kilometer Running Time-Trial Performance in the Heat in Recreationally Active Individuals. Nutrients. 2023 Jan 24;15(3):599. doi: 10.3390/nu15030599.

  PMID: 36771308 BACKGROUND

• Herrera-Amante CA, Garcia-Zepeda G, Garcia-Zepeda CE, Yanez-Sepulveda R, Clemente-Suarez VJ, Lopez-Gil JF, Octavio Ramos-Garcia C. Effects of glycerol hyperhidration on the running economy of long-distance runners: a randomized crossover clinical trial. Front Nutr. 2025 Aug 13;12:1630462. doi: 10.3389/fnut.2025.1630462. eCollection 2025.

  PMID: 40880737 DERIVED

MeSH Terms

Conditions

Motor Activity

Condition Hierarchy (Ancestors)

Behavior

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NA
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: SINGLE GROUP
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Chief Research Officer (CRO)

Study Record Dates

• First Submitted: January 25, 2025
• First Posted: February 10, 2025
• Study Start: November 10, 2022
• Primary Completion: October 13, 2023
• Study Completion: January 13, 2024
• Last Updated: February 10, 2025

Record last verified: 2025-01

Data Sharing

• IPD Sharing: Will not share

Locations

ME (1)