Betaine Addition to Water Loading Prior to Running Exercise

September 18, 2026 updated by: Emilia Zawieja, Poznan University of Life Sciences

Effects of a Betaine-Supplemented Hydration Protocol on Sweat Rate and Exercise Performance in Runners

This randomized, double-blind, placebo-controlled crossover study will investigate whether acute betaine ingestion as part of a pre-exercise hyperhydration strategy improves endurance running performance and influences hydration-related responses during prolonged exercise.

Approximately 30 recreationally trained male and premenopausal female runners will complete two experimental trials: a betaine condition and a placebo/control condition. In the betaine condition, participants will ingest anhydrous betaine at a dose of 0.07 g/kg body mass as part of a standardized pre-exercise hydration protocol providing a total fluid intake of approximately 25 mL/kg body mass.

Following the hydration protocol, participants will complete 60 minutes of treadmill running at 60% of the running velocity corresponding to VO₂max, followed by a 5-minute recovery period and a 5-km treadmill time trial.

The primary outcome will be 5-km running time-trial performance. Secondary outcomes will include exercise-induced fluid and sweat loss, urinary hydration markers, sweat electrolyte concentrations, physiological responses, exercise economy, substrate utilization, blood lactate concentration, perceived exertion, thirst, and thermal sensation.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Not yet recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
20

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

18 years to 45 years (Adult)

Accepts Healthy Volunteers

Yes

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • Age 18-45 years
  • Sex: men and premenopausal women
  • Continuous running training for at least 12 months
  • At least 3 running training sessions per week
  • Willingness and ability to complete the treadmill exercise protocol: 60 minutes of running at 60% of the running velocity corresponding to VO₂max, followed by a 5-km running time trial
  • Medical clearance for participation in maximal and prolonged exercise testing

Exclusion Criteria:

  • Age <18 or >45 years
  • Postmenopausal women
  • Use of betaine, choline, folic acid/folate, or vitamin B12 supplements within 3 months prior to study participation
  • Current musculoskeletal injury or injury occurring within the previous 2 months
  • Uncontrolled arterial hypertension
  • Pregnancy or breastfeeding
  • Diabetes requiring insulin therapy or inadequately controlled diabetes
  • Active or severe liver disease, including ALT or AST >3× the upper limit of normal
  • Renal impairment, including eGFR <60 mL/min/1.73 m²
  • Untreated or unstable thyroid disease, including hypothyroidism or hyperthyroidism
  • Gastrointestinal disease that may affect nutrient absorption
  • Kidney disease, cardiovascular disease, irritable bowel syndrome, or adrenal disease
  • Use of diuretics, SGLT2 inhibitors, laxatives, or glucocorticoids
  • Any medical contraindication to physical exercise and/or failure to obtain medical clearance for exercise testing
  • Elevated body temperature at the time of testing
  • Cystic fibrosis

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Other
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: Triple

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Betaine → Placebo Sequence

Participants will first complete the betaine-enriched hyperhydration condition. After the washout period, they will complete the placebo hyperhydration condition.
Dietary supplement: Anhydrous Betaine

Anhydrous betaine (trimethylglycine) will be administered as a single dose of 0.07 g/kg body mass, dissolved in a commercially available sports drink (5 mL/kg body mass), 150 minutes before exercise. The betaine-containing drink will constitute the first bolus of a standardized pre-exercise hyperhydration protocol providing a total fluid intake of approximately 25 mL/kg body mass over 120 minutes.

Other: Placebo

Participants will receive the same commercially available sports drink (5 mL/kg body mass) without added betaine 150 minutes before exercise. This will be followed by four additional fluid boluses of mineral water (5 mL/kg each) administered at 120, 90, 60, and 30 minutes before exercise, for a total pre-exercise fluid intake of approximately 25 mL/kg body mass.
Experimental: Placebo → Betaine Sequence

Participants will first complete the placebo hyperhydration condition. After the washout period, they will complete the betaine-enriched hyperhydration condition.
Dietary supplement: Anhydrous Betaine

Anhydrous betaine (trimethylglycine) will be administered as a single dose of 0.07 g/kg body mass, dissolved in a commercially available sports drink (5 mL/kg body mass), 150 minutes before exercise. The betaine-containing drink will constitute the first bolus of a standardized pre-exercise hyperhydration protocol providing a total fluid intake of approximately 25 mL/kg body mass over 120 minutes.

Other: Placebo

Participants will receive the same commercially available sports drink (5 mL/kg body mass) without added betaine 150 minutes before exercise. This will be followed by four additional fluid boluses of mineral water (5 mL/kg each) administered at 120, 90, 60, and 30 minutes before exercise, for a total pre-exercise fluid intake of approximately 25 mL/kg body mass.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
5-km Running Time-Trial Performance
Time Frame: During the 5-km treadmill time trial performed after the 60-minute running preload and a 5-minute recovery period in each experimental trial.

Time required to complete a 5-km treadmill running time trial, expressed in seconds. Participants will be instructed to complete the distance as quickly as possible and will be allowed to adjust treadmill speed throughout the trial. Lower completion time indicates better performance.
During the 5-km treadmill time trial performed after the 60-minute running preload and a 5-minute recovery period in each experimental trial.

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Sweat rate
Time Frame: From immediately before the 60-minute running preload to completion of the subsequent 5-km time trial during each experimental trial.

Whole-body sweat rate will be estimated from the change in body mass from immediately before exercise to completion of the 5-km time trial, adjusted for fluid intake and urine output, if applicable, and expressed as L/h. Body mass will be measured using the calibrated electronic scale integrated with the BOD POD system (COSMED, Italy) and expressed in kilograms (kg). Changes in body mass will also be calculated and reported as a percentage of pre-exercise body mass (%).
From immediately before the 60-minute running preload to completion of the subsequent 5-km time trial during each experimental trial.

Other Outcome Measures

Other Outcome Measures

For clinical trials, a planned measurement described in the protocol that is used to determine the effect of an intervention/treatment on participants. For observational studies, a measurement or observation that is used to describe patterns of diseases or traits, or associations with exposures, risk factors, or treatment. Types of outcome measures include primary outcome measure and secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Sweat sodium concentration
Time Frame: Between minutes 30 and 60 of the 60-minute running preload during each experimental trial.

Sodium concentration will be measured in sweat samples collected from standardized sites on the forearm and thigh during exercise. Sweat samples will be collected between minutes 30 and 60 of the 60-minute running preload. Sodium concentration will be analyzed using a HORIBA ion-selective electrode analyzer and reported in mmol/L.
Between minutes 30 and 60 of the 60-minute running preload during each experimental trial.
Sweat Potassium Concentration
Time Frame: Between minutes 30 and 60 of the 60-minute running preload during each experimental trial.

Potassium concentration will be measured in sweat samples collected from standardized sites on the forearm and thigh during exercise. Sweat samples will be collected between minutes 30 and 60 of the 60-minute running preload. Sweat potassium concentration will be analyzed using a HORIBA ion-selective electrode analyzer and reported in mmol/L.
Between minutes 30 and 60 of the 60-minute running preload during each experimental trial.
Blood lactate concentration
Time Frame: Immediately after the 60-minute running preload and immediately after the 5-km time trial during each experimental trial.

Blood lactate concentration will be measured using a portable Lactate Scout 4 analyzer. Measurements will be obtained immediately after completion of the 60-minute running preload and immediately after completion of the subsequent 5-km time trial. Blood lactate concentration will be reported in mmol/L.
Immediately after the 60-minute running preload and immediately after the 5-km time trial during each experimental trial.
Heart rate
Time Frame: Continuously during the 60-minute running preload and the subsequent 5-km time trial in each experimental trial.

Heart rate will be monitored continuously using a Garmin chest-strap heart rate monitor with integrated electrodes throughout the 60-minute running preload and the subsequent 5-km time trial. Outcome variables will include mean heart rate during the 60-minute preload, mean heart rate during the 5-km time trial, and maximal heart rate achieved during the 5-km time trial. Heart rate will be reported in beats per minute (bpm).
Continuously during the 60-minute running preload and the subsequent 5-km time trial in each experimental trial.
Core Body Temperature
Time Frame: Continuously during the 60-minute running preload and the subsequent 5-km time trial in each experimental trial.

Core body temperature will be monitored continuously using a CORE body temperature sensor attached to the Garmin chest strap throughout the 60-minute running preload and the subsequent 5-km time trial. Outcome variables will include mean core body temperature during the exercise protocol and the highest core body temperature recorded during the exercise protocol. Temperature will be reported in degrees Celsius (°C).
Continuously during the 60-minute running preload and the subsequent 5-km time trial in each experimental trial.
Running Economy
Time Frame: During the final 10 minutes (minutes 50-60) of the 60-minute running preload in each experimental trial.

Running economy will be assessed by breath-by-breath indirect calorimetry using a QUARK RMR metabolic system during the final 10 minutes (minutes 50-60) of the 60-minute running preload. Running economy will be quantified as mean oxygen consumption (VO₂) relative to body mass at the standardized running velocity and expressed as mL·kg-¹·min-¹. Lower oxygen consumption at the same running velocity indicates better running economy.
During the final 10 minutes (minutes 50-60) of the 60-minute running preload in each experimental trial.
Respiratory Exchange Ratio
Time Frame: During the final 10 minutes (minutes 50-60) of the 60-minute running preload in each experimental trial.

Respiratory exchange ratio (RER) will be assessed by breath-by-breath indirect calorimetry using a QUARK RMR metabolic system during the final 10 minutes (minutes 50-60) of the 60-minute running preload. RER will be calculated as the ratio of carbon dioxide production (VCO₂) to oxygen consumption (VO₂) and expressed as a unitless value. The mean RER over the measurement period will be used for analysis.
During the final 10 minutes (minutes 50-60) of the 60-minute running preload in each experimental trial.
Urine specific gravity
Time Frame: Immediately before the 60-minute running preload and immediately after completion of the 5-km time trial in each experimental trial.

Urine specific gravity (USG) will be measured using a URIT-31 urine analyzer from urine samples collected immediately before the 60-minute running preload and after completion of the subsequent 5-km time trial. USG will be reported as a dimensionless value. Urine osmolality will also be estimated from USG using a predefined conversion equation and reported in mOsm/kg.
Immediately before the 60-minute running preload and immediately after completion of the 5-km time trial in each experimental trial.
Rating of Perceived Exertion (RPE)
Time Frame: At minutes 30, and 60 of the 60-minute running preload and immediately after completion of the 5-km time trial during each experimental trial.

Rating of perceived exertion will be assessed using the Borg 6-20 Rating of Perceived Exertion scale, ranging from 6 ("no exertion at all") to 20 ("maximal exertion"). RPE will be recorded at 15-minute intervals during the 60-minute running preload and immediately after completion of the 5-km time trial.
At minutes 30, and 60 of the 60-minute running preload and immediately after completion of the 5-km time trial during each experimental trial.
Thirst Sensation
Time Frame: Immediately before the 60-minute running preload, at minutes 30,and 60 of the preload, and immediately after completion of the 5-km time trial during each experimental trial.

Perceived thirst will be assessed using a 9-point categorical thirst sensation scale ranging from 1 ("not thirsty at all") to 9 ("very, very thirsty"). Participants will be asked to rate their current sensation of thirst at each measurement time point.
Immediately before the 60-minute running preload, at minutes 30,and 60 of the preload, and immediately after completion of the 5-km time trial during each experimental trial.
Thermal Sensation
Time Frame: Immediately before the 60-minute running preload, at minutes 30 and 60 of the preload, and immediately after completion of the 5-km time trial during each experimental trial.

Thermal sensation will be assessed using a 17-point thermal sensation scale ranging from 0 to 8 in 0.5-point increments, with 0 representing "unbearably cold", 4 representing "neutral", and 8 representing "unbearably hot". Participants will rate their whole-body thermal sensation at each measurement time point.
Immediately before the 60-minute running preload, at minutes 30 and 60 of the preload, and immediately after completion of the 5-km time trial during each experimental trial.

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Poznan University of Life Sciences

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
October 1, 2026

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
May 31, 2027

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
December 30, 2027

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
September 18, 2026

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
September 18, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
September 25, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
September 25, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
September 18, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
September 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • BETxSWEAT

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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