Energy MetabolismTELENCT06104150
Erythrocyte Transport of Lactate During Exercise (TELE Project)
A study testing Intervallic submaximal exercise test in people with Energy Metabolism, run by Technical University of Madrid at 2 sites in Spain.
Trial summary
The goals of this clinical trial are: 1. to study lactate kinetic between plasma and erythrocytes during an intervallic exercise and its subsequent recovery, considering the blood pH, the genotype for the T1470A polymorphism of the SLC16A1 gene (rs1049434), and the amount of MCT1 in erythrocytes membrane; 2. Read more about this study
- Who is it for?
- Ages 18 to 30 yearsHealthy volunteers can take part
- Conditions the study is for
- Energy Metabolism
- What is being tested?
- Intervallic submaximal exercise test
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 84 participants
- Where
- 2 sitesSpain
- Study dates
- 3 Feb 2020to 31 Jul 2027
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 30 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- BMI between 18 and 25 kg/m2
- Not smoker
- In the case of trained participants: training at least 5 hours/week, of which at least 3 must be aerobic/anaerobic endurance training. Presentation of a medical certificate attesting to their medical fitness (capability) to perform intense physical exercise.
- In the case of sedentary participants, less than 1 day of training per week or less than 2 hours of structured exercise per week.
Who cannot join
- Presenting any pathology that could impede the correct performance of the tests, or could influence the main study variables.
- In the case of the female sample, having irregular menstrual cycles, oligomenorrhea or amenorrhea.
Trial locations and contacts
2 sites in 1 country. Contact the study team or a site near you to ask about taking part.
Spain2 sites, 2 recruiting
- Recruiting
Laboratorio de Fisiología del Esfuerzo. Facultad de Ciencias de la Actividad Física y del Deporte (INEF). Universidad Politécnica de Madrid
Madrid, Madrid, 28040
Ildefonso Fernández, +34910677866, laboratorio.fisiologia.inef@upm.es
Rocío Cupeiro, PhD, +34910677990, rocio.cupeiro@upm.es
- Recruiting
Laboratorio de Pediatría. School of Medicine. Univesidad de Cantabria
Santander, Cantabria, 39011
Teresa Amigo, teresa.amigo@unican.es
Domingo González-Lamuño, PhD
About this study
Official title: Transporte Eritrocitario de Lactato en Ejercicio
The goals of this clinical trial are:
- to study lactate kinetic between plasma and erythrocytes during an intervallic exercise and its subsequent recovery, considering the blood pH, the genotype for the T1470A polymorphism of the SLC16A1 gene (rs1049434), and the amount of MCT1 in erythrocytes membrane;
- to analyze the levels of MCT1 in the erythrocytes membrane according to training status and genotype for the T1470A polymorphism of SLC16A1 (rs1049434).
Read more
For this, the project will have two phases:
- In phase I, trained participants will perform one maximal incremental test and one intervallic submaximal test with a final active recovery.
- Phase II, levels of the MCT1 protein in the erythrocyte membrane will be quantified from trained and sedentary participants.
Read the detailed description
Introduction
Lactate is the end product of glycolysis and has the capacity to be transported from one cell to another, performing numerous functions. This transport is mainly through several monocarboxylate transporters (MCT). The most predominant is MCT1, which transfers lactate bidirectionally depending on the lactate concentration and pH on each side of the membrane. MCT1 is ubiquitous, being present in most human tissues like the erythrocyte membrane, indicating that these cells are capable of carrying lactate throughout the bloodstream. Some studies have described lactate kinetics between the different blood compartments (erythrocyte-plasma) during incremental and steady-state exercises, but not during intermittent exercise and/or recovery after exercise. Moreover, several studies have observed that the function of MCT1 is conditioned by the presence of a genetic variant: the T1470A polymorphism (rs1049434), which involves a substitution of aspartic acid for glutamic acid at position 490 of the protein. Data suggest that an AA (Glu/Glu) genotype for this single nucleotide polymorphism (or SNP) leads to a higher lactate transport capacity than the TT (Arg/Arg) profile. However, no study has analyzed if this SNP directly affects erythrocyte MCT1 function or content Therefore, the two general objectives of this clinical trial are:
- to study lactate kinetic between plasma and erythrocytes during an intervallic exercise and its subsequent recovery, considering the blood pH, the genotype for the T1470A polymorphism of the SLC16A1 gene (rs1049434), and the amount of MCT1 in erythrocytes membrane;
- to analyze the levels of MCT1 in the erythrocytes membrane according to training status and genotype for the T1470A polymorphism of SLC16A1 (rs1049434).
Procedures
The study will be divided into two phases, each of which will be primarily oriented toward achieving one of two general objectives:
- Phase I: Focused primarily on the study of lactate kinetics between blood compartments during exercise.
- Phase II: Focused primarily on the analysis of the amount of MCT1 in the erythrocyte membrane.
For both phases, volunteers will be informed and sign an informed consent form before a blood sample is taken for genotyping. Once the genotype is known, only those participants with AA or TT genotype will be selected.
The tests that will be performed throughout Phase I will be the following:
- Once participants with the genotypes AA and TT are selected, they will perform a step incremental test until exhaustion to determine the first and second lactate threshold. These thresholds will be determined by measuring lactate concentration from capillary blood samples from the earlobe.
- Finally, an intervallic exercise protocol will be performed starting with 1 min rest followed by a 5 min warm up at an intensity equal to 80% of the first lactate threshold. This is followed by 4 sets of 1 min 30 sec at an intensity 20% above the second lactate threshold, with recovery intervals of 5 min at 80% of the first lactate threshold. After the 4 sets, a final recovery of 20 min at 80% of the first lactate threshold will be performed. During this test, capillary blood samples from the earlobe and venous blood samples from the forearm will be analyzed for lactate concentration.
The procedure for the Phase II will be the following:
- Once participants with the genotype AA and TT are selected, venous blood will be extracted from their forearm at rest.
- Physical activity levels from all the participants will be quantified using the International Physical Activity Questionnaire (IPAQ).
- Analysis of the erythrocyte MCT1 protein content by flow cytometry will be performed from the venous blood samples.
- Conditions
- Energy Metabolism
- Being tested
- Intervallic submaximal exercise test
- Keywords
- lactate kinetics, MCT1, erythrocyte lactate, T1470A polymorphism, exercise
- Medical subject headings
- Motor Activity
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Intervallic submaximal exercise testOther
Also called Interval exercise training
Intervallic submáximal exercise test on a cycle ergometer: 5 min warm-up at 80% of First Lactate Threshold (LT1), and subsequent sets of 1.5 min at 20% above the Second Lactate Threshold (LT2) alternated with recoveries of 5 min at 80% of LT1, ending with a 20 min recovery at 80% of LT1.
| Study group | Role | What they receive |
|---|---|---|
| Intervallic submaximal test | Experimental | Intervallic exercise test Receives: Other: Intervallic submaximal exercise test |
What is being measured
The primary outcome is the main question the study is designed to answer.
Plasma-Erythrocyte lactate difference
Difference between lactate concentration inside the erythrocytes and lactate concentration in plasma, expressed in mMol/L (Millimoles Per Liter), from venous blood extracted during the intervallic test from the antecubital vein.
Measured: Through Phase I of the project, only in the intervallic submaximal test. Average of 3 years
Level of Monocarboxylate Transporter 1 in erythrocytes membrane
Protein abundance of the monocarboxylate transporter 1 in erythrocyte membranes. It is measured using flow cytometry, from venous blood extracted from the forearm in rest state.
Measured: Through study completion, average of 5 years, an average of 2 months per participant
Secondary outcomes (4)
Erythrocyte lactate concentration
Lactate concentration inside the erythrocytes, expressed in mMol/L (Millimoles Per Liter), measured in erythrocytes extracted from processed venous blood.
Lactate concentration is measured in the supernatant obtained after the lysis and centrifugation of the solid part of the blood (mainly erythrocytes), separated by centrifugation. Venous blood samples are extracted during the intervallic test from the antecubital vein.
Measured: Through Phase I of the project, only in the intervallic submaximal test. Average of 3 years
Plasma lactate concentration
Lactate concentration, expressed in mMol/L (Millimoles Per Liter), measured in the plasma of centrifugated venous blood, using a lactate analyzer.
Lactate concentration is measured in the plasma obtained from venous blood extracted during the intervallic test from the antecubital vein.
Measured: Through Phase I of the project, only in the intervallic submaximal test. Average of 3 years
Blood lactate concentration
Lactate concentration, expressed in mMol/L (Millimoles Per Liter), measured from whole venous blood extracted during the intervallic test from the antecubital vein.
Measured: Through Phase I of the project, only in the intervallic submaximal test. Average of 3 years
Blood pH
Level of blood pH measured in venous blood extracted during the intervallic test from the antecubital vein.
Measured: Through Phase I of the project, only in the intervallic submaximal test. Average of 3 years
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted27 Oct 2023
- Study start3 Feb 2020
- Primary completion30 Jun 2027 (estimated)
- Study completion31 Jul 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for Energy MetabolismStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Basic science
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Enrolment
- 84 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Technical University of Madrid
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Rocío Cupeiro, PhD, Technical University of Madrid
- Investigators
- Rocío Cupeiro, PhD, Principal investigator, Universidad Politecnica de Madrid
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06104150
- Sponsor's protocol ID
- PINV-18-ENW9ML-92-B2287R
- Acronym
- TELE
- Status last verified
- Sep 2025
- First submitted
- 19 Oct 2023
- Last updated
- 12 Sep 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
Publications
Benitez-Munoz JA, Rojo-Tirado MA, Benito Peinado PJ, Murias JM, Gonzalez-Lamuno D, Cupeiro R. Greater Relative First and Second Lactate Thresholds in Females Compared With Males: Consideration for Exercise Prescription. Int J Sports Physiol Perform. 2024 Oct 28;20(1):30-36. doi: 10.1123/ijspp.2024-0079. Print 2025 Jan 1.
PubMed 39467538
Study at a glance
From the registry record, last updated by the sponsor on 12 Sep 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Transporte Eritrocitario de Lactato en Ejercicio
- ClinicalTrials.gov ID
- NCT06104150
- Acronym / sponsor ID
- TELE / PINV-18-ENW9ML-92-B2287R
- Conditions
- Energy Metabolism
- Keywords
- lactate kinetics, MCT1, erythrocyte lactate, T1470A polymorphism, exercise
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 84 participants (estimated)
- Lead sponsor
- Technical University of MadridUniversity, hospital or other
- Study start
- 3 Feb 2020 (actual)
- Primary completion
- 30 Jun 2027 (estimated)
- Study completion
- 31 Jul 2027 (estimated)
- First posted
- 27 Oct 2023 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The goals of this clinical trial are:
- to study lactate kinetic between plasma and erythrocytes during an intervallic exercise and its subsequent recovery, considering the blood pH, the genotype for the T1470A polymorphism of the SLC16A1 gene (rs1049434), and the amount of MCT1 in erythrocytes membrane;
- to analyze the levels of MCT1 in the erythrocytes membrane according to training status and genotype for the T1470A polymorphism of SLC16A1 (rs1049434).
For this, the project will have two phases:
- In phase I, trained participants will perform one maximal incremental test and one intervallic submaximal test with a final active recovery.
- Phase II, levels of the MCT1 protein in the erythrocyte membrane will be quantified from trained and sedentary participants.
Detailed description
Introduction
Lactate is the end product of glycolysis and has the capacity to be transported from one cell to another, performing numerous functions. This transport is mainly through several monocarboxylate transporters (MCT). The most predominant is MCT1, which transfers lactate bidirectionally depending on the lactate concentration and pH on each side of the membrane. MCT1 is ubiquitous, being present in most human tissues like the erythrocyte membrane, indicating that these cells are capable of carrying lactate throughout the bloodstream. Some studies have described lactate kinetics between the different blood compartments (erythrocyte-plasma) during incremental and steady-state exercises, but not during intermittent exercise and/or recovery after exercise. Moreover, several studies have observed that the function of MCT1 is conditioned by the presence of a genetic variant: the T1470A polymorphism (rs1049434), which involves a substitution of aspartic acid for glutamic acid at position 490 of the protein. Data suggest that an AA (Glu/Glu) genotype for this single nucleotide polymorphism (or SNP) leads to a higher lactate transport capacity than the TT (Arg/Arg) profile. However, no study has analyzed if this SNP directly affects erythrocyte MCT1 function or content Therefore, the two general objectives of this clinical trial are:
- to study lactate kinetic between plasma and erythrocytes during an intervallic exercise and its subsequent recovery, considering the blood pH, the genotype for the T1470A polymorphism of the SLC16A1 gene (rs1049434), and the amount of MCT1 in erythrocytes membrane;
- to analyze the levels of MCT1 in the erythrocytes membrane according to training status and genotype for the T1470A polymorphism of SLC16A1 (rs1049434).
Procedures
The study will be divided into two phases, each of which will be primarily oriented toward achieving one of two general objectives:
- Phase I: Focused primarily on the study of lactate kinetics between blood compartments during exercise.
- Phase II: Focused primarily on the analysis of the amount of MCT1 in the erythrocyte membrane.
For both phases, volunteers will be informed and sign an informed consent form before a blood sample is taken for genotyping. Once the genotype is known, only those participants with AA or TT genotype will be selected.
The tests that will be performed throughout Phase I will be the following:
- Once participants with the genotypes AA and TT are selected, they will perform a step incremental test until exhaustion to determine the first and second lactate threshold. These thresholds will be determined by measuring lactate concentration from capillary blood samples from the earlobe.
- Finally, an intervallic exercise protocol will be performed starting with 1 min rest followed by a 5 min warm up at an intensity equal to 80% of the first lactate threshold. This is followed by 4 sets of 1 min 30 sec at an intensity 20% above the second lactate threshold, with recovery intervals of 5 min at 80% of the first lactate threshold. After the 4 sets, a final recovery of 20 min at 80% of the first lactate threshold will be performed. During this test, capillary blood samples from the earlobe and venous blood samples from the forearm will be analyzed for lactate concentration.
The procedure for the Phase II will be the following:
- Once participants with the genotype AA and TT are selected, venous blood will be extracted from their forearm at rest.
- Physical activity levels from all the participants will be quantified using the International Physical Activity Questionnaire (IPAQ).
- Analysis of the erythrocyte MCT1 protein content by flow cytometry will be performed from the venous blood samples.
Study design
- Primary purpose
- Basic science
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Intervallic submaximal test | Experimental | Other: Intervallic submaximal exercise testIntervallic exercise test |
Who may qualify
- Ages
- 18 to 30 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (4 listed)
- BMI between 18 and 25 kg/m2
- Not smoker
- In the case of trained participants: training at least 5 hours/week, of which at least 3 must be aerobic/anaerobic endurance training. Presentation of a medical certificate attesting to their medical fitness (capability) to perform intense physical exercise.
- In the case of sedentary participants, less than 1 day of training per week or less than 2 hours of structured exercise per week.
Key exclusion criteria (2 listed)
- Presenting any pathology that could impede the correct performance of the tests, or could influence the main study variables.
- In the case of the female sample, having irregular menstrual cycles, oligomenorrhea or amenorrhea.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Intervallic submaximal exercise testAlso: Interval exercise trainingIntervallic submáximal exercise test on a cycle ergometer: 5 min warm-up at 80% of First Lactate Threshold (LT1), and subsequent sets of 1.5 min at 20% above the Second Lactate Threshold (LT2) alternated with recoveries of 5 min at 80% of LT1, ending with a 20 min recovery at 80% of LT1. | Other | Intervallic submaximal test |
Primary outcome
Plasma-Erythrocyte lactate difference
Time frame: Through Phase I of the project, only in the intervallic submaximal test. Average of 3 years
Difference between lactate concentration inside the erythrocytes and lactate concentration in plasma, expressed in mMol/L (Millimoles Per Liter), from venous blood extracted during the intervallic test from the antecubital vein.
Level of Monocarboxylate Transporter 1 in erythrocytes membrane
Time frame: Through study completion, average of 5 years, an average of 2 months per participant
Protein abundance of the monocarboxylate transporter 1 in erythrocyte membranes. It is measured using flow cytometry, from venous blood extracted from the forearm in rest state.
4 secondary outcomes
Erythrocyte lactate concentration
Time frame: Through Phase I of the project, only in the intervallic submaximal test. Average of 3 years
Plasma lactate concentration
Time frame: Through Phase I of the project, only in the intervallic submaximal test. Average of 3 years
Blood lactate concentration
Time frame: Through Phase I of the project, only in the intervallic submaximal test. Average of 3 years
Blood pH
Time frame: Through Phase I of the project, only in the intervallic submaximal test. Average of 3 years
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 12 Sep 2025.
- Derived from this study: PubMed 39467538Benitez-Munoz JA, Rojo-Tirado MA, Benito Peinado PJ, Murias JM, Gonzalez-Lamuno D, Cupeiro R. Greater Relative First and Second Lactate Thresholds in Females Compared With Males: Consideration for Exercise Prescription. Int J Sports Physiol Perform. 2024 Oct 28;20(1):30-36. doi: 10.1123/ijspp.2024-0079. Print 2025 Jan 1.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Rocío Cupeiro, PhD principal investigator
Universidad Politecnica de Madrid
2 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Intervallic submaximal exercise test in people with Energy Metabolism, run by Technical University of Madrid at 2 sites in Spain.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 4 inclusion and 2 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 12 Sep 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 2 sites in Spain. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Rocío Cupeiro, PhD (+34910677990, rocio.cupeiro@upm.es), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Plasma-Erythrocyte lactate difference (time frame: Through Phase I of the project, only in the intervallic submaximal test. Average of 3 years). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT06104150, which also lists 1 linked publication.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 12 Sep 2025.