Effect of Molecular Hydrogen Administration on Performance and Body Response on Exercise in National-level Fin-swimmers

June 2, 2026 updated by: Jakub Krejci, Palacky University

Effect of Molecular Hydrogen Administration on Performance and Body Response on Repeated Exercise and the Following Recovery in National-level Fin-swimmers: A Randomized, Double-blind, Placebo-controlled Crossover Trial

The aim of this randomized, double-blind, placebo-controlled crossover trial is to evaluate the effect of hydrogen-rich water consumption on performance, recovery, psychological and biochemical outcomes in elite Czech fin-swimmers.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

Twelve Czech national and international-level fin-swimmers participate in this trial. Participants take molecular hydrogen via drinking hydrogen-rich water (HRW) or placebo three days before (1260 ml/day) and during testing day (2520 ml). All participants participate in two testing session and receive HRW and placebo in random order. Each session includes two training units in a 25-m indoor swimming pool and a 24-hour monitored recovery. The first training unit takes place in the morning between 9 and 11 AM and includes three high intensity interval sets. The afternoon training unit includes a continuous 400-m competitive performance. The washout period between testing sessions is 7 days. The variables assessed are as follows: swimming times, heart rate variability, lower limb explosive strength, rating of perceived exertion, subjective perceived muscle soreness, creatine kinase, blood lactate, and protein carbonyls. Statistical analysis is based on analysis of variance for repeated measures with factors: water (HRW and placebo), time, and interaction. Fisher's post-hoc tests is used for pairwise comparisons. The significance level is set at 0.05.

Study Type

Interventional

Enrollment (Actual)

14

Phase

  • 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 Locations

  • Czechia
      • Olomouc, Czechia, 77111
        • Palacky University, Faculty of Physical Culture

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

Ages Eligible for Study

16 years to 30 years (Child, Adult)

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • Junior or adult Czech fin-swimming representative.
  • Medical eligibility for competitive sport.
  • Good health condition.
  • Signed informed consent.

Exclusion Criteria:

  • Acute health problems.
  • Not following instructions (free of any supplements three weeks before experiment, free of any medicaments, no caffeine at least 24 hours before experiment).
  • Menstruation in testing session.

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: Prevention
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: Double

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Molecular hydrogen
Hydrogen-rich water supplied in 420-ml packages. 3 days before testing day - 3 packages per day, testing day - 6 packages, 15 packages in total.
Dietary supplement: Hydrogen rich water
Hydrogen-rich water with molecular hydrogen concentration 0.9 ppm.
Other Names:
  • Aquastamina-R, Nutristamina, Ostrava, Czech Republic
Placebo Comparator: Placebo
Tap water supplied in 420-ml packages. 3 days before testing day - 3 packages per day, testing day - 6 packages, 15 packages in total.
Dietary supplement: Placebo
Tap water with molecular hydrogen concentration 0.0 ppm.
Other Names:
  • Aquastamina-Placebo, Nutristamina, Ostrava, Czech Republic

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Swimming time for 400 m
Time Frame: Change between values before and after 7 days of crossover.
Swimming time is recorded according to swimming and fin-swimming rules. Swimming time is measured by two qualified timekeepers. The longer time is the official time.
Change between values before and after 7 days of crossover.

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Swimming time for 50 m
Time Frame: Change between values before and after 7 days of crossover.
Swimming time is recorded according to swimming and fin-swimming rules. Swimming time is measured by three qualified timekeepers. If two of the three watches record the same time and the third disagrees, the two identical times is the official time. If all three watches disagree, the watch recording the intermediate time is the official time. The 50-m swimming is repeated in 3 sets and 4 rounds, representing 12 measured times.
Change between values before and after 7 days of crossover.
Heart rate variability
Time Frame: Change between values before and after 7 days of crossover.
To determine heart rate variability variables, the ECG signal is measured at a sampling frequency of 1000 Hz using DiANS PF8 (DIMEA Group, Olomouc, Czech Republic). ECG sampling is performed during an orthoclinostatic maneuver (supine-standing-supine) in calm room without any acoustic or visual disturbances. Time domain variables (RMSSD and SDNN) and frequency domain variables (high and low frequency power) are calculated from the ECG. Variables are measured before and after the first training unit, before and after the second training unit, morning and evening of the following day.
Change between values before and after 7 days of crossover.
Lower limb explosive strength
Time Frame: Change between values before and after 7 days of crossover.
The subject performs 3 single maximum effort countermovement jumps with 30 seconds of rest between each jump. The starting position for the jump is an upright posture with the hands placed on the hips. Vertical ground reaction force is measured on 2 parallel force platforms (AMTI OR6-7-1000, Advanced Mechanical Technology, Watertown, USA) with a sampling frequency of 1000 Hz. The jump height is calculated from the measured force-time curve and the average of three jumps is considered for subsequent analysis. The jump height is measured before and after the first training unit, before and after the second training unit, morning and evening of the following day.
Change between values before and after 7 days of crossover.
Rating of perceived exertion
Time Frame: Change between values before and after 7 days of crossover.
The subject is asked to score subjective rating of perceived exertion using the scale developed by Borg. All subjects are familiar with the Borg scale before testing. We use modified scale ranged from 1 (no exertion at all) to 10 (maximum exertion). The rating is scored immediately after each set of 50-m swimming and after 400-m swimming.
Change between values before and after 7 days of crossover.
Subjective perceived muscle soreness
Time Frame: Change between values before and after 7 days of crossover.
Visual analogue scale (VAS) is used to assess lower limb muscle soreness. The VAS is a horizontal 100 mm length line, marked with 0, indicating "no pain" and 100 indicating the "worst imaginable pain". The VAS is assessed before and after the first training unit, before and after the second training unit, morning and evening of the following day.
Change between values before and after 7 days of crossover.
Creatine kinase
Time Frame: Change between values before and after 7 days of crossover.
Creatine kinase is evaluated based on blood samples taken from fingertip. An alcohol wipe is used to clean fingertip and the skin is punctured with lancet. First drop is wiped away and the second drop is used. A Reflotron applicator with a 32 μL disposable pipette tip is used to extract a 32 μL sample of blood and place it on a creatine kinase assay strip (Reflotron CK strips, Roche Diagnostics, Rotkreuz, Switzerland). The blood sample is analyzed using a spectrophotometer (Reflotron Plus, Roche Diagnostics, Rotkreuz, Switzerland) to set plasma creatine kinase concentration.The creatine kinase is evaluated before the first training unit, before the second training unit, morning and evening of the following day.
Change between values before and after 7 days of crossover.
Blood lactate
Time Frame: Change between values before and after 7 days of crossover.
Blood lactate concentration is evaluated based on blood samples taken from fingertip. An alcohol wipe is used to clean fingertip and the skin will be punctured with lancet. First drop is wiped away and the second drop is be used. For lactate sampling the analyzer Lactate Scout+ (EKF Diagnostics, Cardiff, United Kingdom) is used. The blood lactate is evaluated before the first training unit, after each set of 50-m swimming, after swim-up, before and after the second training unit, morning and evening of the following day.
Change between values before and after 7 days of crossover.
Protein carbonyls
Time Frame: Change between values before and after 7 days of crossover.
Protein carbonyls are detected from vein blood sample which is taken from the inside of the elbow by a healthcare specialist. The blood is taken into heparinized vacuum tubes. These is then centrifuged at 1000 g. Subsequently, the blood plasma is separated into cryotubes and frozen at -80 °C until biochemical analysis. Protein carbonyls concentration is measured by ELISA method in accordance with the manufacturer's manual (Protein carbonyl content assay kit, Sigma-Aldrich, Saint Louis, USA). The protein carbonyls is analyzed before the first training unit, before the second training unit, morning and evening of the following day.
Change between values before and after 7 days of crossover.

Collaborators and Investigators

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

Sponsor

Palacky University

Investigators

  • Principal Investigator: Barbora Sladeckova, MSc, Palacky University

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

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 (Actual)

April 11, 2023

Primary Completion (Actual)

May 31, 2023

Study Completion (Actual)

May 31, 2023

Study Registration Dates

First Submitted

March 10, 2023

First Submitted That Met QC Criteria

April 4, 2023

First Posted (Actual)

April 5, 2023

Study Record Updates

Last Update Posted (Actual)

June 4, 2026

Last Update Submitted That Met QC Criteria

June 2, 2026

Last Verified

June 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • FTK_2023_11

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

Anonymised raw data will be made available.

IPD Sharing Time Frame

The data will be available once the results are published in a scientific journal.

IPD Sharing Access Criteria

For everybody.

Study Data/Documents

  1. Individual Participant Data Set
    Information comments: Botek M, Krejčí J, Sládečková B. Dataset for "Autonomic cardiac regulation in response to exercise and molecular hydrogen administration in well-trained athletes". Zenodo; 2026.
  2. Individual Participant Data Set
    Information comments: Sládečková B, Botek M, Krejčí J, Valenta M, McKune A, Neuls F, Klimešová I. Supplementary material for "Hydrogen-rich water supplementation promotes muscle recovery after two strenuous training sessions performed on the same day in elite fin swimmers: randomized, double-blind, placebo-controlled, crossover trial". Front. Physiol.; 2024.
  3. Individual Participant Data Set
    Information comments: Sládečková B, Krejčí J, Bajgar R, Botek M. Dataset for "Hydrogen-rich water as a performance enhancing aid in national-level finswimmers: A randomized, double-blind, placebo-controlled crossover study". Zenodo; 2026.

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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