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| Name | Class |
|---|---|
| University of Guadalajara | OTHER |
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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:
The researchers will conduct a clinical trial with 30 runners (15 men, 15 women) in three sessions. In the first session, VO2peak was determined and running speeds were established for sessions 2 and 3. In the second session, participants performed a stress test. In the second session, participants performed a running test in the euhydrated state under fluid restriction, and in the third session, with glycerol supplementation (22 ml/kg sports drink + 1.2 g/kg glycerol). Variables such as caloric cost unit (CCU), oxygen cost unit (OCU), heart rate (HR), body temperature (BT) and perceived exertion (RPE) were evaluated.
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| Label | Type | Description | Intervention Names |
|---|---|---|---|
| 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 (VOâ‚‚max), 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. |
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| Name | Type | Description | Arm Group Labels | Other Names |
|---|---|---|---|---|
| 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. |
| Measure | Description | Time Frame |
|---|---|---|
| Maximal oxygen consumption (VOâ‚‚peak) (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 |
| Measure | Description | Time Frame |
|---|---|---|
| Body temperature | The temperature will be measured during the running economy evaluation with an infrared thermometer (Berrcom® JXB-178). | 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. |
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Inclusion Criteria:
Exclusion Criteria:
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.
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| Facility | Status | City | State | ZIP | Country | Contacts |
|---|---|---|---|---|---|---|
| Universidad de Guadalajara, Centro Universitario de Tonalá | Guadalajara | Jalisco | 45425 | Mexico |
| PubMed Identifier | Type | Citation | Retractions |
|---|---|---|---|
| 36771308 | Background | 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. | |
| 40880737 | Derived |
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| ID | Term |
|---|---|
| D009043 | Motor Activity |
| ID | Term |
|---|---|
| D001519 | Behavior |
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| Perception of exertion |
The Borg effort perception scale, with a range of scores from 6 to 20, was used during the three sessions, recording the perception of effort in each minute of the test according to the following classification:
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| It was applied during the evaluation of the stress tests to determine the Vo2peak and Running Economy. |
| Sweating rate. | Fluctuations in body mass between the different sessions were evaluated. | 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. |
| 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. |