HealthySBEPNCT07171047
Effects of Sodium Bicarbonate on Endurance Performance
A study of Healthy and Athlete, run by University of Salzburg at 1 site in Austria.
Trial summary
This study is investigating whether taking sodium bicarbonate, a common supplement used by endurance athletes, can improve cycling performance during prolonged exercise and in a time trial. Sodium bicarbonate may help reduce muscle acidity, which could delay fatigue and improve performance. Read more about this study
- Who is it for?
- Ages 16 to 50 yearsHealthy volunteers can take part
- Conditions the study is for
- Healthy, Athlete, Well-trained Athletes
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 19 participants
- Where
- 1 siteAustria
- Study dates
- 15 Sep 2025to 12 Dec 2025
- Phase
- Interventional
- Are there results?
- None posted in the registry
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 16 to 50 years
- All sexes
- Healthy volunteers accepted
- Child, Adult
Who may be able to join
- age 16-50 years
- well-trained cyclists
- Proof of physical fitness (e.g. sports medical examination required) for measurements with higher intensities (e.g. endurance tests, competition simulation)
- >10h endurance training per week
Who cannot join
- Systemic disease or other known pathology in the organs: heart, lungs, kidney, stomach, spleen, liver, gall bladder, and intestines.
- Evidence of pulmonary disease: forced expiratory volume in one second/forced expiratory volume < 70% with/without symptoms (cough, sputum) or other evidence of pulmonologic disease.
- Diabetes II.
Trial locations and contacts
1 site in 1 country.
Austria1 site
Red Bull Athlete Performance Center
Thalgau, State of Salzburg, 5303
About this study
Official title: Effects of Sodium Bicarbonate Supplementation on Endurance Performance and Physiological Responses During Simulated Cycling Competition
This study is investigating whether taking sodium bicarbonate, a common supplement used by endurance athletes, can improve cycling performance during prolonged exercise and in a time trial. Sodium bicarbonate may help reduce muscle acidity, which could delay fatigue and improve performance. The goal of this study is to determine if this supplement can help athletes perform better during long, intense efforts like those seen in real competitions.
Participants in this study are well-trained cyclists who will complete two exercise trials in a laboratory setting. Each trial involves three hours of moderate cycling followed by a 20-30-minute time trial at maximum effort. Before each trial, participants will take either sodium bicarbonate or a placebo.
The study will measure performance outcomes, such as time trial results, as well as physiological responses, including heart rate, oxygen use, and muscle fatigue. Researchers hope to better understand how sodium bicarbonate can help endurance athletes and provide guidelines for its use in competitive sports.
- Conditions
- Healthy, Athlete, Well-trained Athletes, Performance
- Being tested
- Placebo then Verum, Verum then Placebo
- Keywords
- Bicarbonate, Endurance training, Cycling, Time trial
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Placebo then VerumDietary supplement
Intake of 0.3 g/kg bodyweight of maltodextrin with hydrogel as placebo and 0.3 g/kg bodyweight of sodium bicarbonate with hydrogel as Verum
Verum then PlaceboDietary supplement
Intake of 0.3 g/kg bodyweight of maltodextrin with hydrogel as placebo and 0.3 g/kg bodyweight of sodium bicarbonate with hydrogel as Verum
| Study group | Role | What they receive |
|---|---|---|
| Placebo then Verum | Other | Placebo then Verum 3 hour low-intensity ride followed by a 16 km time trial for both conditions. Supplementation of Placebo or Verum before the exercise start. Receives: Dietary Supplement: Placebo then Verum |
| Verum then Placebo | Other | Verum then Placebo 3 hour low-intensity ride followed by a 16 km time trial for both conditions. Supplementation of Placebo or Verum before the exercise start. Receives: Dietary Supplement: Verum then Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
Endurance performance
Difference in time trial performance (average power in watts) between placebo and verum condition
Measured: 20-30 minutes, immediately after completion of the time trial for each condition (Placebo and Verum), assessed on test day 1 and test day 2 respectively, with a washout period of 3-7 days between appointments (test days).
Secondary outcomes (16)
Difference in questionnaire score - gastrointestinal symptoms
Difference in questionnaire score gastrointestinal symptoms between placebo and verum condition (0-10, higher score indicates more severe symptoms).
Measured: 6.5 hours (rest, breakfast, every 30min during 3-hour low-intensity, after TT) for each condition (Placebo and Verum), on test day 1 and test day 2 respectively, with a washout period of 3-7 days between appointments (test days).
Difference in questionnaire score - Energy & Confidence
Difference in questionnaire score energy and confidence in time trial performance between placebo and verum condition (0-10, higher score indicates more Energy or Confidence in time trial performance).
Measured: 3 hours (every 30min during 3-hour low-intensity) for each condition (Placebo and Verum), assessed on test day 1 and test day 2 respectively, with a washout period of 3-7 days between appointments (test days).
Difference in questionnaire score - rate of perceived exertion
Difference in questionnaire score overall and legs only perceived exertion between placebo and verum condition (0-10, higher score indicates a higher degree of perceived exertion).
Measured: 3.5 hours (every 30min during 3-hour low-intensity, after TT) for each condition (Placebo and Verum), assessed on test day 1 and test day 2 respectively, with a washout period of 3-7 days between appointments (test days).
Difference in blood count
Difference in capillary blood count between placebo and verum condition
Measured: 6.5 hours (rest, every 30min during 3-hour low-intensity, after TT) for each condition (Placebo and Verum), assessed on test day 1 and test day 2 respectively, with a washout period of 3-7 days between appointments (test days).
Difference in pH & HCO3 kinetics
Difference in pH \& HCO3 kinetics between placebo, verum and resting verum condition
Measured: 6.5 hours (rest, breakfast, every 30min during 3-hour low-intensity, after TT) for each condition (Placebo and Verum), on test day 1 and test day 2 respectively, with a washout period of 3-7 days between appointments (test days).
Difference in heart rate
Difference in heart rate (bpm) between placebo and verum condition
Measured: 3.5 hours, assessed continuously (every second) during 3 hour low-intensity and TT for each condition (Placebo and Verum), on test day 1 and test day 2 respectively, with a washout period of 3-7 days between appointments (test days).
Difference in oxygen uptake
Difference in oxygen uptake (ml/kg/min) between placebo and verum condition
Measured: 3 hours, assessed for 5 min every 30 min during 3 hour low-intensity for each condition (Placebo and Verum), on test day 1 and test day 2 respectively, with a washout period of 3-7 days between appointments (test days).
Difference in blood lactate concentration
Difference in blood lactate concentration (mmol/L) between placebo and verum condition.
Measured: 3.5 hours, assessed every 30 min during 3 hour low-intensity and after TT for each condition (Placebo and Verum), on test day 1 and test day 2 respectively, with a washout period of 3-7 days between appointments (test days).
Difference in substrate utilization
Difference in substrate utilization between placebo and verum condition.
Measured: 3 hours, assessed for 5 min every 30 min during 3 hour low-intensity for each condition (Placebo and Verum), on test day 1 and test day 2 respectively, with a washout period of 3-7 days between appointments (test days).
Difference in ventilation
Difference in ventilation (L/min) between placebo and verum condition
Measured: 3 hours, assessed for 5 min every 30 min during 3 hour low-intensity for each condition (Placebo and Verum), on test day 1 and test day 2 respectively, with a washout period of 3-7 days between appointments (test days).
Difference in core body temperature
Difference in core body temperature (°) between placebo and verum condition.
Measured: 3.5 hours, assessed continuously during 3 hour low-intensity and TT for each condition (Placebo and Verum), on test day 1 and test day 2 respectively, with a washout period of 3-7 days between appointments (test days).
Difference in muscle oxygenation
Difference in muscle oxygenation (SmO2) of the vastus lateralis between placebo and verum condition.
Measured: 3.5 hours, assessed continuously during 3 hour low-intensity and TT for each condition (Placebo and Verum), on test day 1 and test day 2 respectively, with a washout period of 3-7 days between appointments (test days).
Difference in glucose level
Difference in glucose level (mg/dl) between placebo and verum condition.
Measured: 24 hours, assessed continuously for each condition (Placebo and Verum), on test day 1 and test day 2 respectively, with a washout period of 3-7 days between appointments (test days).
Difference in sodium content
Difference in sodium content (mg/hr) between placebo and verum condition
Measured: 3.5 hours, assessed during 3 hour low-intensity and TT for each condition (Placebo and Verum), on test day 1 and test day 2 respectively, with a washout period of 3-7 days between appointments (test days).
Difference in sweat rate
Difference in sweat rate (L/hr) between placebo and verum condition.
Measured: 3.5 hours, assessed during 3 hour low-intensity and TT for each condition (Placebo and Verum), on test day 1 and test day 2 respectively, with a washout period of 3-7 days between appointments (test days).
Difference in next morning weight
Difference in weight (kg) measured in the morning of the test day and the following day (before breakfast after urination and defecation)
Measured: 24 hours, assessed in the morning for each condition (Placebo and Verum) and the following day, on test day 1 and test day 2 respectively, with a washout period of 3-7 days between appointments (test days).
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted12 Sep 2025
- Study start15 Sep 2025
- Primary completion12 Dec 2025
- Study completion12 Dec 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for HealthyStudies 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
- Treatment
- Allocation
- Randomised
- Intervention model
- Crossover
- Model description
- Double blinded two-intervention crossover study
- Masking
- Double blind
- Who is masked
- Participant, Investigator
- Enrolment
- 19 participants (actual)
Sponsor and investigators
- Lead sponsor
- University of Salzburg
- Sponsor type
- University, hospital or other
- Collaborators
- Red Bull Athlete Performance Center
- Responsible party
- Principal investigator, Nils Haller, PhD, University of Salzburg
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07171047
- Sponsor's protocol ID
- BICARB_Haller
- Acronym
- SBEP
- Status last verified
- Mar 2026
- First submitted
- 25 Jul 2025
- Last updated
- 30 Mar 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided
Study at a glance
From the registry record, last updated by the sponsor on 30 Mar 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Effects of Sodium Bicarbonate Supplementation on Endurance Performance and Physiological Responses During Simulated Cycling Competition
- ClinicalTrials.gov ID
- NCT07171047
- Acronym / sponsor ID
- SBEP / BICARB_Haller
- Conditions
- Healthy, Athlete, Well-trained Athletes, Performance
- Keywords
- Bicarbonate, Endurance training, Cycling, Time trial
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 19 participants (actual)
- Lead sponsor
- University of SalzburgUniversity, hospital or other
- Collaborators
- Red Bull Athlete Performance Center
- Study start
- 15 Sep 2025 (actual)
- Primary completion
- 12 Dec 2025 (actual)
- Study completion
- 12 Dec 2025 (actual)
- First posted
- 12 Sep 2025 (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.
This study is investigating whether taking sodium bicarbonate, a common supplement used by endurance athletes, can improve cycling performance during prolonged exercise and in a time trial. Sodium bicarbonate may help reduce muscle acidity, which could delay fatigue and improve performance. The goal of this study is to determine if this supplement can help athletes perform better during long, intense efforts like those seen in real competitions.
Participants in this study are well-trained cyclists who will complete two exercise trials in a laboratory setting. Each trial involves three hours of moderate cycling followed by a 20-30-minute time trial at maximum effort. Before each trial, participants will take either sodium bicarbonate or a placebo.
The study will measure performance outcomes, such as time trial results, as well as physiological responses, including heart rate, oxygen use, and muscle fatigue. Researchers hope to better understand how sodium bicarbonate can help endurance athletes and provide guidelines for its use in competitive sports.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Double blind (participant, investigator)
- Number of arms
- 2
- Model description
- Double blinded two-intervention crossover study
| Arm | Type | Receives |
|---|---|---|
| Placebo then Verum | Other | Dietary Supplement: Placebo then VerumPlacebo then Verum 3 hour low-intensity ride followed by a 16 km time trial for both conditions. Supplementation of Placebo or Verum before the exercise start. |
| Verum then Placebo | Other | Dietary Supplement: Verum then PlaceboVerum then Placebo 3 hour low-intensity ride followed by a 16 km time trial for both conditions. Supplementation of Placebo or Verum before the exercise start. |
Who may qualify
- Ages
- 16 to 50 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Child, Adult
Key inclusion criteria (4 listed)
- age 16-50 years
- well-trained cyclists
- Proof of physical fitness (e.g. sports medical examination required) for measurements with higher intensities (e.g. endurance tests, competition simulation)
- >10h endurance training per week
Key exclusion criteria (3 listed)
- Systemic disease or other known pathology in the organs: heart, lungs, kidney, stomach, spleen, liver, gall bladder, and intestines.
- Evidence of pulmonary disease: forced expiratory volume in one second/forced expiratory volume < 70% with/without symptoms (cough, sputum) or other evidence of pulmonologic disease.
- Diabetes II.
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 |
|---|---|---|
| Placebo then VerumIntake of 0.3 g/kg bodyweight of maltodextrin with hydrogel as placebo and 0.3 g/kg bodyweight of sodium bicarbonate with hydrogel as Verum | Dietary supplement | Placebo then Verum |
| Verum then PlaceboIntake of 0.3 g/kg bodyweight of maltodextrin with hydrogel as placebo and 0.3 g/kg bodyweight of sodium bicarbonate with hydrogel as Verum | Dietary supplement | Verum then Placebo |
Primary outcome
Endurance performance
Time frame: 20-30 minutes, immediately after completion of the time trial for each condition (Placebo and Verum), assessed on test day 1 and test day 2 respectively, with a washout period of 3-7 days between appointments (test days).
Difference in time trial performance (average power in watts) between placebo and verum condition
16 secondary outcomes
Difference in questionnaire score - gastrointestinal symptoms
Time frame: 6.5 hours (rest, breakfast, every 30min during 3-hour low-intensity, after TT) for each condition (Placebo and Verum), on test day 1 and test day 2 respectively, with a washout period of 3-7 days between appointments (test days).
Difference in questionnaire score - Energy & Confidence
Time frame: 3 hours (every 30min during 3-hour low-intensity) for each condition (Placebo and Verum), assessed on test day 1 and test day 2 respectively, with a washout period of 3-7 days between appointments (test days).
Difference in questionnaire score - rate of perceived exertion
Time frame: 3.5 hours (every 30min during 3-hour low-intensity, after TT) for each condition (Placebo and Verum), assessed on test day 1 and test day 2 respectively, with a washout period of 3-7 days between appointments (test days).
Difference in blood count
Time frame: 6.5 hours (rest, every 30min during 3-hour low-intensity, after TT) for each condition (Placebo and Verum), assessed on test day 1 and test day 2 respectively, with a washout period of 3-7 days between appointments (test days).
Difference in pH & HCO3 kinetics
Time frame: 6.5 hours (rest, breakfast, every 30min during 3-hour low-intensity, after TT) for each condition (Placebo and Verum), on test day 1 and test day 2 respectively, with a washout period of 3-7 days between appointments (test days).
Difference in heart rate
Time frame: 3.5 hours, assessed continuously (every second) during 3 hour low-intensity and TT for each condition (Placebo and Verum), on test day 1 and test day 2 respectively, with a washout period of 3-7 days between appointments (test days).
Difference in oxygen uptake
Time frame: 3 hours, assessed for 5 min every 30 min during 3 hour low-intensity for each condition (Placebo and Verum), on test day 1 and test day 2 respectively, with a washout period of 3-7 days between appointments (test days).
Difference in blood lactate concentration
Time frame: 3.5 hours, assessed every 30 min during 3 hour low-intensity and after TT for each condition (Placebo and Verum), on test day 1 and test day 2 respectively, with a washout period of 3-7 days between appointments (test days).
Difference in substrate utilization
Time frame: 3 hours, assessed for 5 min every 30 min during 3 hour low-intensity for each condition (Placebo and Verum), on test day 1 and test day 2 respectively, with a washout period of 3-7 days between appointments (test days).
Difference in ventilation
Time frame: 3 hours, assessed for 5 min every 30 min during 3 hour low-intensity for each condition (Placebo and Verum), on test day 1 and test day 2 respectively, with a washout period of 3-7 days between appointments (test days).
Difference in core body temperature
Time frame: 3.5 hours, assessed continuously during 3 hour low-intensity and TT for each condition (Placebo and Verum), on test day 1 and test day 2 respectively, with a washout period of 3-7 days between appointments (test days).
Difference in muscle oxygenation
Time frame: 3.5 hours, assessed continuously during 3 hour low-intensity and TT for each condition (Placebo and Verum), on test day 1 and test day 2 respectively, with a washout period of 3-7 days between appointments (test days).
Difference in glucose level
Time frame: 24 hours, assessed continuously for each condition (Placebo and Verum), on test day 1 and test day 2 respectively, with a washout period of 3-7 days between appointments (test days).
Difference in sodium content
Time frame: 3.5 hours, assessed during 3 hour low-intensity and TT for each condition (Placebo and Verum), on test day 1 and test day 2 respectively, with a washout period of 3-7 days between appointments (test days).
Difference in sweat rate
Time frame: 3.5 hours, assessed during 3 hour low-intensity and TT for each condition (Placebo and Verum), on test day 1 and test day 2 respectively, with a washout period of 3-7 days between appointments (test days).
Difference in next morning weight
Time frame: 24 hours, assessed in the morning for each condition (Placebo and Verum) and the following day, on test day 1 and test day 2 respectively, with a washout period of 3-7 days between appointments (test days).
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 30 Mar 2026.
- Individual participant dataSharing planned: Undecided
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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. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study of Healthy and Athlete, run by University of Salzburg at 1 site in Austria.
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 3 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: finished, as of the sponsor's last update on 30 Mar 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Austria. 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?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Endurance performance (time frame: 20-30 minutes, immediately after completion of the time trial for each condition (Placebo and Verum), assessed on test day 1 and test day 2 respectively, with a washout period of 3-7 days between appointments (test days).). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
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 30 Mar 2026.