Betaine Addition to Water Loading Prior to Running Exercise

NCT07840248 | Not Yet Recruiting

• 1 other identifier: BETxSWEAT
• Study Type: interventional
• Target: 20
• Locations: 0 countries
• Sites: N/A

Brief Summary

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.

Conditions

Exercise; Hydration

Keywords

betaine; hydration; endurance; exercise

Outcome Measures

Primary Outcomes (1)

• 5-km Running Time-Trial Performance

  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 Outcomes (1)

• Sweat rate

  From immediately before the 60-minute running preload to completion of the subsequent 5-km time trial during each experimental trial.

Other Outcomes (11)

• Sweat sodium concentration

  Between minutes 30 and 60 of the 60-minute running preload during each experimental trial.

• Sweat Potassium Concentration

  Between minutes 30 and 60 of the 60-minute running preload during each experimental trial.

• Blood lactate concentration

  Immediately after the 60-minute running preload and immediately after the 5-km time trial during each experimental trial.

Study Arms (2)

Betaine → Placebo Sequence

EXPERIMENTAL

Participants will first complete the betaine-enriched hyperhydration condition. After the washout period, they will complete the placebo hyperhydration condition.

Dietary Supplement: Anhydrous Betaine; Other: Placebo

Placebo → Betaine Sequence

EXPERIMENTAL

Participants will first complete the placebo hyperhydration condition. After the washout period, they will complete the betaine-enriched hyperhydration condition.

Dietary Supplement: Anhydrous Betaine; Other: Placebo

Interventions

Anhydrous Betaine DIETARY_SUPPLEMENT

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.

Betaine → Placebo Sequence; Placebo → Betaine Sequence

Placebo OTHER

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.

Betaine → Placebo Sequence; Placebo → Betaine Sequence

Eligibility Criteria

• Age: 18 Years - 45 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• 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

You may not qualify if:

• 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

Sponsors & Collaborators

• Poznan University of Life Sciences: lead

MeSH Terms

Conditions

Motor Activity

Condition Hierarchy (Ancestors)

Behavior

Central Study Contacts

Emilia Zawieja

CONTACT

+48500415726; emilia.zawieja@up.poznan.pl

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: TRIPLE
• Who Masked: PARTICIPANT, INVESTIGATOR, OUTCOMES ASSESSOR
• Purpose: OTHER
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: PhD

Study Record Dates

• First Submitted: September 18, 2026
• First Posted: September 25, 2026
• Study Start: October 1, 2026
• Primary Completion (Estimated): May 31, 2027
• Study Completion (Estimated): December 30, 2027
• Last Updated: September 25, 2026

Record last verified: 2026-09