Sweat RateTOSSNCT07464743
Time Onset Sweat Sodium (TOSS) Study
A study testing Exercise in the heat in people with Sweat Rate and Heat Effect, run by University of Arkansas, Fayetteville.
Trial summary
Prior to each trial, you will be provided with urine jugs and food/fluid logs to record food and drink intake for 24hr. You will be asked to log food/fluid intake 24hr leading into trials. We ask that you match your diet for both trials, as much as possible. Read more about this study
- Who is it for?
- Ages 18 to 49 yearsHealthy volunteers can take part
- Conditions the study is for
- Sweat Rate, Heat Effect, Sweat Sodium Concentration
- What is being tested?
- Exercise in the heat
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 40 participants
- Where
- No sites listed yet
- Study dates
- 16 Feb 2026to Aug 2026
- 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 49 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- Regular exercisers
- Otherwise healthy individuals
- Capable of running/jogging or cycling for 120min straight
Who cannot join
- Heat illness in the past 3 years
- Taking medications that alter fluid balance or Na retention
- Chronic conditions that contraindicate long duration exercise in the heat
Trial locations and contacts
No sites are listed yet. Contact the study team or a site near you to ask about taking part.
About this study
Prior to each trial, you will be provided with urine jugs and food/fluid logs to record food and drink intake for 24hr. You will be asked to log food/fluid intake 24hr leading into trials. We ask that you match your diet for both trials, as much as possible. Also, we ask that you match caffeine consumption prior to trials. Lastly, we ask that you refrain from strenuous exercise and alcohol consumption for at least 12hrs leading into trials. Either of these exclude your participation in the study for safety reasons. You will be asked to provide a small urine sample upon arrival to the lab before trials. The purpose of this is to verify hydration prior to exercise in the heat. If you are not hydrated upon arrival, you will be provided and asked to drink 16oz (a bottle) of water prior to the trial. Just prior to, and following each long trial, you will be asked to provide a small saliva sample. To do this, you will be asked to actively produce saliva and guide it into a small container. This process takes <5min. Next, you will have your nude body mass measured and you will be instrumented with a labbased sweat collection patch (large band-aid on the forearm), and the Hdrop sweat detection device on your left upper arm. The Hdrop will be synced with electronic applications (phone apps) to assure data collection. You will then self-insert a rectal thermistor ~15 cm past the anal sphincter to monitor core temperature throughout exercise (for safety purposes). You will also be fitted with a heart rate strap that goes around your chest. You will then be asked to enter the environmental chamber and exercise for 30min. This will serve as the short exercise trial aiming to assure comfort with the 120min exercise trials. Data will be collected during the short trial and comparisons will be made for the longer, 120min trials. The environmental chamber will maintain a consistent temperature (80-100 degrees F) and humidity (40 to 60 % relative humidity). You will be monitored for safety throughout exercise in all 3 trials, and you will be allowed to cycle (stationary bike) or run or walk (treadmill) at your own pace/intensity. Pace and intensity will be recorded during the first trial and attempts will be made to match exercise intensity for subsequent trials. Fluid consumption will be allowed during trials and will be matched between trials. In both trials, you will be allowed to drink for a 5min period at each 30min interval (30-35min, 60-65min and 90-95min). We will provide a sport drink of your flavor choice during exercise.
Read the detailed description
If you agree to be in this study, you will be asked to report to our exercise science research center for three total visits (1 short trial and 2 separate trials separated by at least 4 days), and the total time commitment for this study will be approximately 7 hours. Prior to each trial, you will be provided with urine jugs and food/fluid logs to record food and drink intake for 24hr. You will be asked to log food/fluid intake 24hr leading into trials. We ask that you match your diet for both trials, as much as possible. Also, we ask that you match caffeine consumption prior to trials. Lastly, we ask that you refrain from strenuous exercise and alcohol consumption for at least 12hrs leading into trials. Either of these excludes your participation in the study for safety reasons. You will be asked to provide a small urine sample upon arrival to the lab before trials. The purpose of this is to verify hydration prior to exercise in the heat. If you are not hydrated upon arrival, you will be provided and asked to drink 16oz (a bottle) of water prior to the trial. Next, you will have your nude body mass measured, and you will be instrumented with a lab-based sweat collection patch (large band-aid on the forearm), and the Hdrop sweat detection device on your left upper arm. The Hdrop will be synced with electronic applications (phone apps) to assure data collection. You will then self-insert a rectal thermistor ~15 cm past the anal sphincter to monitor core temperature during exercise (for safety). You will also be fitted with a heart rate strap that goes around your chest. The first trial will involve only 30min of exercise. You will be asked to enter the environmental chamber and exercise for 30 minutes for the first trial. The participant will self-select the pace of the exercise (walk/run/cycle). The pace they will select is one they think they can maintain for 2 hours of exercising. If they need to adjust their pace, they will. The environmental chamber will maintain a consistent temperature (80-100 degrees F) and humidity (40-60% relative humidity). The second and third trials will be self-selected in terms of exercise intensity - participant chooses the intensity. Participants will be monitored for safety throughout exercise, and you will be allowed to cycle (stationary bike) or run or walk (treadmill) at your own pace/intensity. Pace and intensity will be recorded during the first trial. Subsequent trials will attempt to be matched for exercise intensity. The first trial is to familiarize participants with the protocol and environment to be sure they will be able to complete trials. Fluid consumption will be allowed during trials. In both long trials researchers will replace 80% of sweat rate losses with a sport drink during the trial. The other trial will be matched for fluid consumption. Prior to, and following, the last 2 (longer trials - 120min exercise), participants will be a asked to provide a saliva sample. This normally takes about 5min and is done by thinking of food and attempting to "drool" into a small container. This is for a hydration test to compare to urine samples provided at the same 2 time points (before and after long trials). Exercise trials will be stopped if you experience signs/symptoms of heat illness, get exhausted, or no longer want to continue. Following the exercise, sweat collection devices will be collected and analyzed for sweat electrolyte concentration and/or sweat rate detection. Upon completion of exercise, you will towel dry and have nude body mass measured again. All devices, heart rate strap and rectal thermistor will be returned. You will be provided fluids and snacks following exercise and be monitored for 15min. Following this, you will be allowed to leave, and you will be scheduled for your second trial. Following your second trial, you will be compensated for participation.
- Conditions
- Sweat Rate, Heat Effect, Sweat Sodium Concentration
- Being tested
- Exercise in the heat
- Keywords
- Sweat rate, Exercise in the heat, Sweat sodium, Validity
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Exercise in the heatOther
Our trials will be conducted in an environmental chamber set to 80-100 degrees F and 40-60 relative humidity.
| Study group | Role | What they receive |
|---|---|---|
| Short trial (30min exercise in the heat) | Other | Short trial. We will assess sweat rate and sweat-sodium losses during exercise in the heat. Receives: Other: Exercise in the heat |
| Long trials (120min exercise in the heat) | Other | Long trial. we will assess sweat rate and sweat-sodium losses during exercise in the heat. We will also determine if 30min exercise trials accurately predict fluid and Na losses during 120min exercise in the heat. Receives: Other: Exercise in the heat |
What is being measured
The primary outcome is the main question the study is designed to answer.
Sweat rate (L/hr)
Sweat rate is measured as body mass changes during exercise in the heat.
Measured: 0-30min; 30-60min; 60-90min; 90-120min - Every 30min during exercise in the heat
Sweat [Na]
Sweat [Na] will be assessed via sweat patches applied during exercise in the heat.
Measured: Every 30min during trails with exercise in the heat.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted11 Mar 2026
- Study start16 Feb 2026 (estimated)
- Primary completionMay 2026 (estimated)
- Study completionAug 2026 (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 Sweat RateStudies 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
- Other
- Allocation
- Non-randomised
- Intervention model
- Single group
- Model description
- Participants will complete 3 trials each. One trial is 30min in duration, while the last 2 are 120min, involving exercise in the heat. The longer trials will be matched.
- Masking
- None (open label)
- Enrolment
- 40 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University of Arkansas, Fayetteville
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Brendon P. McDermott, University of Arkansas, Fayetteville
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07464743
- Sponsor's protocol ID
- 2509625720
- Acronym
- TOSS
- Status last verified
- Mar 2026
- First submitted
- 2 Mar 2026
- Last updated
- 11 Mar 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes: All de-identified data will be available through clinicaltrials.gov and reasonable requests made to corresponding authors once manuscripts have been submitted for publication.
Publications
Bandiera D, de Bardonneche J, Margout-Jantac D, Dubois L, El Allaoui N, Rubio JSE, Aubin JC, Racinais S, Tessitore A, Pitsiladis Y. Sweat sodium composition and sweat loss estimation through wearable sensors and predictive equations in dry and humid hot conditions. Front Physiol. 2026 Jan 5;16:1717275. doi: 10.3389/fphys.2025.1717275. eCollection 2025.
PubMed 41561158
Study at a glance
From the registry record, last updated by the sponsor on 11 Mar 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Time Onset Sweat Sodium (TOSS) Study
- ClinicalTrials.gov ID
- NCT07464743
- Acronym / sponsor ID
- TOSS / 2509625720
- Conditions
- Sweat Rate, Heat Effect, Sweat Sodium Concentration
- Keywords
- Sweat rate, Exercise in the heat, Sweat sodium, Validity
- Study type
- Interventional
- Recruitment status
- Not yet recruiting
- Enrolment
- 40 participants (estimated)
- Lead sponsor
- University of Arkansas, FayettevilleUniversity, hospital or other
- Study start
- 16 Feb 2026 (estimated)
- Primary completion
- May 2026 (estimated)
- Study completion
- Aug 2026 (estimated)
- First posted
- 11 Mar 2026 (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.
Prior to each trial, you will be provided with urine jugs and food/fluid logs to record food and drink intake for 24hr. You will be asked to log food/fluid intake 24hr leading into trials. We ask that you match your diet for both trials, as much as possible. Also, we ask that you match caffeine consumption prior to trials. Lastly, we ask that you refrain from strenuous exercise and alcohol consumption for at least 12hrs leading into trials. Either of these exclude your participation in the study for safety reasons. You will be asked to provide a small urine sample upon arrival to the lab before trials. The purpose of this is to verify hydration prior to exercise in the heat. If you are not hydrated upon arrival, you will be provided and asked to drink 16oz (a bottle) of water prior to the trial. Just prior to, and following each long trial, you will be asked to provide a small saliva sample. To do this, you will be asked to actively produce saliva and guide it into a small container. This process takes <5min. Next, you will have your nude body mass measured and you will be instrumented with a labbased sweat collection patch (large band-aid on the forearm), and the Hdrop sweat detection device on your left upper arm. The Hdrop will be synced with electronic applications (phone apps) to assure data collection. You will then self-insert a rectal thermistor ~15 cm past the anal sphincter to monitor core temperature throughout exercise (for safety purposes). You will also be fitted with a heart rate strap that goes around your chest. You will then be asked to enter the environmental chamber and exercise for 30min. This will serve as the short exercise trial aiming to assure comfort with the 120min exercise trials. Data will be collected during the short trial and comparisons will be made for the longer, 120min trials. The environmental chamber will maintain a consistent temperature (80-100 degrees F) and humidity (40 to 60 % relative humidity). You will be monitored for safety throughout exercise in all 3 trials, and you will be allowed to cycle (stationary bike) or run or walk (treadmill) at your own pace/intensity. Pace and intensity will be recorded during the first trial and attempts will be made to match exercise intensity for subsequent trials. Fluid consumption will be allowed during trials and will be matched between trials. In both trials, you will be allowed to drink for a 5min period at each 30min interval (30-35min, 60-65min and 90-95min). We will provide a sport drink of your flavor choice during exercise.
Detailed description
If you agree to be in this study, you will be asked to report to our exercise science research center for three total visits (1 short trial and 2 separate trials separated by at least 4 days), and the total time commitment for this study will be approximately 7 hours. Prior to each trial, you will be provided with urine jugs and food/fluid logs to record food and drink intake for 24hr. You will be asked to log food/fluid intake 24hr leading into trials. We ask that you match your diet for both trials, as much as possible. Also, we ask that you match caffeine consumption prior to trials. Lastly, we ask that you refrain from strenuous exercise and alcohol consumption for at least 12hrs leading into trials. Either of these excludes your participation in the study for safety reasons. You will be asked to provide a small urine sample upon arrival to the lab before trials. The purpose of this is to verify hydration prior to exercise in the heat. If you are not hydrated upon arrival, you will be provided and asked to drink 16oz (a bottle) of water prior to the trial. Next, you will have your nude body mass measured, and you will be instrumented with a lab-based sweat collection patch (large band-aid on the forearm), and the Hdrop sweat detection device on your left upper arm. The Hdrop will be synced with electronic applications (phone apps) to assure data collection. You will then self-insert a rectal thermistor ~15 cm past the anal sphincter to monitor core temperature during exercise (for safety). You will also be fitted with a heart rate strap that goes around your chest. The first trial will involve only 30min of exercise. You will be asked to enter the environmental chamber and exercise for 30 minutes for the first trial. The participant will self-select the pace of the exercise (walk/run/cycle). The pace they will select is one they think they can maintain for 2 hours of exercising. If they need to adjust their pace, they will. The environmental chamber will maintain a consistent temperature (80-100 degrees F) and humidity (40-60% relative humidity). The second and third trials will be self-selected in terms of exercise intensity - participant chooses the intensity. Participants will be monitored for safety throughout exercise, and you will be allowed to cycle (stationary bike) or run or walk (treadmill) at your own pace/intensity. Pace and intensity will be recorded during the first trial. Subsequent trials will attempt to be matched for exercise intensity. The first trial is to familiarize participants with the protocol and environment to be sure they will be able to complete trials. Fluid consumption will be allowed during trials. In both long trials researchers will replace 80% of sweat rate losses with a sport drink during the trial. The other trial will be matched for fluid consumption. Prior to, and following, the last 2 (longer trials - 120min exercise), participants will be a asked to provide a saliva sample. This normally takes about 5min and is done by thinking of food and attempting to "drool" into a small container. This is for a hydration test to compare to urine samples provided at the same 2 time points (before and after long trials). Exercise trials will be stopped if you experience signs/symptoms of heat illness, get exhausted, or no longer want to continue. Following the exercise, sweat collection devices will be collected and analyzed for sweat electrolyte concentration and/or sweat rate detection. Upon completion of exercise, you will towel dry and have nude body mass measured again. All devices, heart rate strap and rectal thermistor will be returned. You will be provided fluids and snacks following exercise and be monitored for 15min. Following this, you will be allowed to leave, and you will be scheduled for your second trial. Following your second trial, you will be compensated for participation.
Study design
- Primary purpose
- Other
- Allocation
- Non-randomised
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 2
- Model description
- Participants will complete 3 trials each. One trial is 30min in duration, while the last 2 are 120min, involving exercise in the heat. The longer trials will be matched.
| Arm | Type | Receives |
|---|---|---|
| Short trial (30min exercise in the heat) | Other | Other: Exercise in the heatShort trial. We will assess sweat rate and sweat-sodium losses during exercise in the heat. |
| Long trials (120min exercise in the heat) | Other | Other: Exercise in the heatLong trial. we will assess sweat rate and sweat-sodium losses during exercise in the heat. We will also determine if 30min exercise trials accurately predict fluid and Na losses during 120min exercise in the heat. |
Who may qualify
- Ages
- 18 to 49 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (3 listed)
- Regular exercisers
- Otherwise healthy individuals
- Capable of running/jogging or cycling for 120min straight
Key exclusion criteria (3 listed)
- Heat illness in the past 3 years
- Taking medications that alter fluid balance or Na retention
- Chronic conditions that contraindicate long duration exercise in the heat
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 |
|---|---|---|
| Exercise in the heatOur trials will be conducted in an environmental chamber set to 80-100 degrees F and 40-60 relative humidity. | Other | Long trials (120min exercise in the heat), Short trial (30min exercise in the heat) |
Primary outcome
Sweat rate (L/hr)
Time frame: 0-30min; 30-60min; 60-90min; 90-120min - Every 30min during exercise in the heat
Sweat rate is measured as body mass changes during exercise in the heat.
Sweat [Na]
Time frame: Every 30min during trails with exercise in the heat.
Sweat [Na] will be assessed via sweat patches applied during exercise in the heat.
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 11 Mar 2026.
- Background: PubMed 41561158Bandiera D, de Bardonneche J, Margout-Jantac D, Dubois L, El Allaoui N, Rubio JSE, Aubin JC, Racinais S, Tessitore A, Pitsiladis Y. Sweat sodium composition and sweat loss estimation through wearable sensors and predictive equations in dry and humid hot conditions. Front Physiol. 2026 Jan 5;16:1717275. doi: 10.3389/fphys.2025.1717275. eCollection 2025.
- Individual participant dataSharing planned: Yes. All de-identified data will be available through clinicaltrials.gov and reasonable requests made to corresponding authors once manuscripts have been submitted for publication.
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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.
Questions about this trial
What is this clinical trial studying?
A study testing Exercise in the heat in people with Sweat Rate and Heat Effect, run by University of Arkansas, Fayetteville.
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 3 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: opening soon, as of the sponsor's last update on 11 Mar 2026. Status can change between updates, so confirm with the study contact before making plans.
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 Brendon P. McDermott, PhD (14795754670, brendonm@uark.edu), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Sweat rate (L/hr) (time frame: 0-30min; 30-60min; 60-90min; 90-120min - Every 30min during exercise in the heat). 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 NCT07464743, 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 11 Mar 2026.