ClinicalTrials.gg
CompletedNCT05295836Updated Mar 25, 2022

Effects of Acute Glycerol Ingestion on Performance, Metabolic and Biochemical Markers in International Athletes

An interventional study of PLACEBO and GLYCEROL in Performance Enhancing Product Use, Change, Body Weight and Change, Body Temperature, sponsored by Francisco Javier Martínez Noguera. Completed at 1 site in Spain. Open to male participants aged 25 Years to 35 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2022-03-25.

Sponsored by Francisco Javier Martínez Noguera · Not applicable, Interventional, and Treatment

Phase
Not applicable
Study type
Interventional
Enrollment
4
Allocation
Randomized
Ages
25 Years to 35 Years
Sex
Male
01

Study summary

This clinical study evaluates the acute effect of glycerol ingestion on performance (power output), weight, urine specific gravity, biochemical (antioxidants and lactate) and metabolic (indirect calorimetry) markers in international athletes in hot conditions. The investigators hypothesized that acute glycerol ingestion can prevent performance loss (power generated at submaximal intensity) in hot conditions. To justify this hypothesis, the investigators will measure the aforementioned markers, which could establish a cause-effect relationship between acute glycerol intake and decreased performance loss in hot conditions.

Read the detailed description

All participants will be informed about the procedures and provide signed informed consent. The study will be conducted according to the guidelines of the Helsinki Declaration for Human Research and the protocol was approved by the Ethics Committee/Institutional Review Catholic University of Murcia (Code: CE091802).

Study design

This is a randomized crossover study. There are 3 types of intervention: water intake of 26 mL/kg/weight at 16°C (CON), 26 mL/kg/weight + placebo at 28°C (PLA) and intake of 1.2 g glycerol + 26 mL/kg/weight at 28°C (GLY). In addition, athletes will be instructed to take a individualized diet in relation to macronutrients (verified by dietary record) and they will follow their adjusted training schedule so that there would be no effect on the tests. Participants in both groups will be instructed not to consume supplements 3 weeks prior to the start of the study.

Procedures

Participants will visit the laboratory on five occasions. Visit 1 consists of a medical examination and a blood draw to determine health status. At visit 2, after a dinner the night before and a standard breakfast, an incremental test will be performed to determine the exercise zones in the rectangular test. At visits 3, 4 and 5, a record of the diet (individually set) will be performed regarding the former 7 days, followed by a rectangular treadmill test.

Visit 1:

Health status blood test: A general blood test will be performed. The blood will be drawn through a vein. (Fasting) Medical examination: A medical history of family and personal history, an electrocardiogram (ECG) at rest and a medical examination (auscultation, blood pressure, etc.) will be carried out to certify that the person is healthy and is not at risk to participate in the study. (Fasting)

Visits 2:

Incremental test with final ramp test will be performed on a cycle ergometer using a metabolic cart (Metalyzer 3B. Leipzig, Germany) to determine maximal fat oxidation zone (FatMax), ventilatory thresholds 1 (VT1) and 2 (VT2) and maximal oxygen consumption (VO2max). Participants will begin cycling at 35W for 2 min, increasing then by 35W every 2 min until RER>1.05, initializing then the final ramp (+35W·min-1) until exhaustion.

Visits 3:

The rectangular test will be performed on a treadmill using the speed values obtained in the incremental test (15 sets x 2 min at 95% with 2:30 recovery at 85% of maximum speed between sets). Cardiorespiratory variables (VO2, VCO2, VO2R, VE/VO2, VE/VCO2, VE/VCO2, respiratory coefficient, respiratory frequency, carbohydrate oxidation (CHO), fat oxidation (FAT), running economy and energy expenditure) will be determined in the 1st, 5th, 10th and 15th series.

For power measurement, each participant will wear the Stryd power meter, which is an inertial sensor (9.1 g) mounted on the foot, firmly attached to the shoe and according to the manufacturer's recommendations. The device stores at a sampling rate of 1 Hz the following variables: estimated power (PO), pace, cadence, leg sprint stiffness (LSS), form power, form power ratio, ground contact time (GCT), vertical oscillation, stride length. These variables will then be determined in the 1st, 5th, 10th and 15th series of the rectangular test. According to information from the Stryd team, the device is operational out of the box and should not require any calibration, accepting a measurement error of 3 percent. Participants will fill in their height and body mass prior to use, which is required for PO estimation. The firmware version that will be used is 2.1.16 (released in August 2020).

For lactate and antioxidant measurements, a Lactate Pro 2 meter and eBQC lab will be used on finger capillary blood at rest, after the 5th, 10th and after completion of the rectangular test.

For body temperature, the investigators will use an infrared thermographic camera (FLIR) to measure heat distribution (head, trunk, lower and upper limbs in both anterior and posterior aspects of the body).

Urine Samples Urine will be collected from the intake of water or water + glycerol or water + placebo until the start of the rectangular test and up to one hour after the rectangular test. The volume of urine excreted pre and post rectangular test will be recorded and the urine specific gravity will be analyzed.

02

Conditions studied

  • Performance Enhancing Product Use
  • Change, Body Weight
  • Change, Body Temperature
  • Antioxidative Stress
  • Lactate Blood Increase
  • Thermal Sensation Disorders

Keywords

  • Power
  • Performance
  • Thermography
  • Metabolism
  • Endurance Sport
  • Ergogenic Aids
  • Oxygen uptake
  • Hydration
  • Hyperhydration
03

In context

Body Weight Changes

231 studies on the registry are indexed under Body Weight Changes; 30 are open to participants now.

This study's enrollment of 4 is below the median of 80 across 179 interventional studies indexed under Body Weight Changes.

Browse Body Weight Changes studies →

Lead sponsor

Francisco Javier Martínez Noguera is the lead sponsor of 6 studies on the registry; 4 are open to participants now.

Counted across the registry records on this site, refreshed daily.

04

Who can participate

Ages eligible
25 Years to 35 Years
Sexes eligible
Male
Accepts healthy volunteers
Yes

Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.

Inclusion criteria

  • Be an international athlete with the Spanish national athletics team.

Exclusion criteria

Exclusion Criteria:

  • Are smokers or regular alcohol drinkers,
  • Have a metabolic, cardiorespiratory or digestive pathology or anomaly,
  • Have an injury in the prior 6 months
  • Are supplementing or medicating in the prior 2 weeks
  • Have non-normal values in the blood analysis parameters.
05

Study design

Phase
Not applicable
Primary purpose
Treatment
Allocation
Randomized
Intervention model
Crossover assignment
Masking
Single (Participant)
Enrollment
4 participants (actual)

Study arms

  • No intervention
    CONTROL

    In this phase of the study, the rectangular test will be performed in conditions of 16°C and 25-30% humidity, intaking 26 mL/kg/body weight of water one and a half hours before the test.

  • Placebo comparator
    PLACEBO (PLA)

    In this intervention, subjects will perform the rectangular test at 28°C and 25-30% humidity, ingesting 26 mL/kg/body weight of water and placebo one and a half hours before the test.

    Other: PLACEBO

  • Experimental
    GLYCEROL (GLY)

    In this intervention, subjects will perform the rectangular test at 28°C and 25-30% humidity, ingesting 1.2 g + 26 mL/kg/body weight of water one and a half hours before the test.

    Dietary Supplement: GLYCEROL

Interventions

  • OtherPLACEBO

    Athletes will perform the rectangular test at a temperature of 28°C and ingested 26 mL/kg body weight + placebo one and half hours before the test.

  • Dietary supplementGLYCEROL

    Athletes will perform the rectangular test at a temperature of 28°C and ingested 26 mL/kg body weight + 1.2 g of glycerol one and half hours before the test.

06

What researchers measure

Primary outcomes

  1. Body weight

    Record body weight before and after the rectangular test

    Time frame: Throughout study completion, an average of 3 weeks

  2. Urine specific gravity

    Record urine specific gravity by means a digital refractometer (Atago) before and after the rectangular test

    Time frame: Throughout study completion, an average of 3 weeks

  3. Power output

    Record the power produced by means the stryd sensor (shoe) in the 1st, 5th, 10th and 15th series of the rectangular test

    Time frame: Throughout study completion, an average of 3 weeks

  4. Body temperature

    Record body temperature by thermography of the head, trunk, and lower limbs, anterior and posterior in rest, after 5th and 10th series, and after completion of the rectangular test

    Time frame: Throughout study completion, an average of 3 weeks

Secondary outcomes

  1. Lactate

    Record lactate in rest, after 5th and 10th series, and after completion of the rectangular test

    Time frame: Throughout study completion, an average of 3 weeks

  2. Measurement of fast- and slow-acting antioxidants (Q1 and Q2) and total antioxidant capacity by a portable analyzer eBQC0101

    Record the antioxidant markers in rest, after 5th and 10th series, and after completion of the rectangular test

    Time frame: Throughout study completion, an average of 3 weeks

  3. Heart rate

    Record the heart rat in rest,1th, 5th, 10th and 15th series of the rectangular test

    Time frame: Throughout study completion, an average of 3 weeks

  4. VO2

    Record the oxygen uptake (L/min) in 1th, 5th, 10th and 15th series of the rectangular test

    Time frame: Throughout study completion, an average of 3 weeks

  5. CO2

    Record the carbon dioxide exhalation (L/min) in 1th, 5th, 10th and 15th series of the rectangular test

    Time frame: Throughout study completion, an average of 3 weeks

  6. RER

    Record respiratory exchange ratio in 1th, 5th, 10th and 15th series of the rectangular test

    Time frame: Throughout study completion, an average of 3 weeks

  7. VE

    Record ventilation (L/min) in 1th, 5th, 10th and 15th series of the rectangular test

    Time frame: Throughout study completion, an average of 3 weeks

  8. FAT ox

    Record fat oxidation (g/h) in 1th, 5th, 10th and 15th series of the rectangular test

    Time frame: Throughout study completion, an average of 3 weeks

  9. HC ox

    Record carbohydrate oxidation (g/h) in 1th, 5th, 10th and 15th series of the rectangular test

    Time frame: Throughout study completion, an average of 3 weeks

  10. FR

    Record respiratory frequency (breaths/min) in 1th, 5th, 10th and 15th series of the rectangular test

    Time frame: Throughout study completion, an average of 3 weeks

  11. EE

    Record energy expenditure (kcal/h) in 1th, 5th, 10th and 15th series of the rectangular test

    Time frame: Throughout study completion, an average of 3 weeks

  12. V'E/V'O2

    Record ventilatory equivalents for oxygen (L/min) in 1th, 5th, 10th and 15th series of the rectangular test

    Time frame: Throughout study completion, an average of 3 weeks

  13. V'E/V'CO2

    Record ventilatory equivalents for carbon dioxide (L/min) in 1th, 5th, 10th and 15th series of the rectangular test

    Time frame: Throughout study completion, an average of 3 weeks

  14. VO2/R

    Record oxygen consumption relative to weight (mL/min/kg) in 1th, 5th, 10th and 15th series of the rectangular test

    Time frame: Throughout study completion, an average of 3 weeks

  15. Cadence

    Record cadence (steps per minute) in 1th, 5th, 10th and 15th series of the rectangular test

    Time frame: Throughout study completion, an average of 3 weeks

  16. Leg spring stiffness

    Record leg spring stiffness (kN/m) in 1th, 5th, 10th and 15th series of the rectangular test

    Time frame: Throughout study completion, an average of 3 weeks

  17. Form power ratio

    Record form power ratio in 1th, 5th, 10th and 15th series of the rectangular test

    Time frame: Throughout study completion, an average of 3 weeks

  18. Form power

    Record form power (W) in 1th, 5th, 10th and 15th series of the rectangular test

    Time frame: Throughout study completion, an average of 3 weeks

  19. Ground contact time

    Record ground contact time (ms) in 1th, 5th, 10th and 15th series of the rectangular test

    Time frame: Throughout study completion, an average of 3 weeks

  20. Vertical oscillation

    Record vertical oscillation (cm) in 1th, 5th, 10th and 15th series of the rectangular test

    Time frame: Throughout study completion, an average of 3 weeks

  21. PO/R

    Record power output relative to weight (W/kg) in 1th, 5th, 10th and 15th series of the rectangular test

    Time frame: Throughout study completion, an average of 3 weeks

07

Study locations

1 site
  • Research Center for High Performance Sport. Catholic University of Murcia
    La Ñora, Murcia 30830, Spain
08

References and documents

09

Timeline

Tracking since Sep 25, 2026
ElapsedEstimatedEstimated, not yet reachedSimilar studies: half by the dot; the band is the middle halfHalf of similar studies reached it by the dot; the band is the middle half, from a quarter to three quarters

Ran from Feb 2022 to primary completion in Feb 2022, 0 months.

Of 90 non-industry interventional studies with no phase under Body Weight Changes, half reached primary completion within 12 months of starting (the median), counting those still running; a quarter within 5 and three quarters within 28. This study's 0 months is below that.

Counting every sponsor, half of 99 studies reached it within 12 months; a quarter within 5 and three quarters within 27.

How these figures are worked out, and which studies are left out of them.

Registered
Feb 24, 2022
First posted
Mar 25, 2022
StartActual
Feb 10, 2022
Primary completionActual
Feb 25, 2022
CompletionActual
Feb 25, 2022
Last update
Mar 25, 2022
What these dates mean
Start.
When the first participant enrolled; while estimated, when the study expects to open to recruitment.
Primary completion.
When the last participant was examined or treated to collect data for the study's main question, its primary outcome. A study that stopped early gives the date its data collection stopped.
Completion.
When the last participant's last visit took place, for every outcome, secondary ones and side effects included: the end of the study. Often later than primary completion, sometimes the same day.
Actual and Est.
Actual means the registry says the date has happened. Est. (estimated) is a date the sponsor plans or expects. It can still move, and the sponsor is expected to change it to actual once it has passed.
No changes since tracking began. The registry record was last updated on Mar 25, 2022, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗
10

Registry details

Key details

Study ID
NCT05295836
Lead sponsor
Francisco Javier Martínez Noguera
Responsible party
Francisco Javier Martínez Noguera (Study coordinator (Investigator), Universidad Católica San Antonio de Murcia) — Sponsor-investigator
First posted
Mar 25, 2022
Start date
Feb 10, 2022
Primary completion
Feb 25, 2022
Completion
Feb 25, 2022
Last update
Mar 25, 2022

Study contacts

Francisco Javier Martínez Noguera, PhD
study chair · Research Center for High Performance Sport. Catholic University of Murcia

Oversight

Data monitoring committee
No
FDA-regulated drug
No
FDA-regulated device
No
View the source record on ClinicalTrials.gov ↗

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Studies of the drug tested here: Glycerol

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