Healthy Adult MaleNCT07064512
The Effect of Heat Exposure on Physiological Markers
A study testing Endogenous heating and Exogenous heating in people with Healthy Adult Male, run by Lithuanian Sports University at 1 site in Lithuania.
Trial summary
This study is the first to examine the effects of core temperature elevation on kynurenine pathway (KP) metabolites in healthy young males. It was hypothesized that rise in core temperature due to both pasive heating and exercise will initiate a stress response, affecting the concentration of KP metabolites. Read more about this study
- Who is it for?
- Ages 18 to 36 years, men onlyHealthy volunteers can take part
- Conditions the study is for
- Healthy Adult Male
- What is being tested?
- Endogenous heating and Exogenous heating
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 11 participants
- Where
- 1 siteLithuania
- Study dates
- 11 Jan 2021to 12 Mar 2021
- 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 18 to 36 years
- Men only
- Healthy volunteers accepted
- Adult
Who may be able to join
- healthy adults;
- age between 18 - 36 years;
- physically active (exercising 2-3 times per week);
- non-smoking.
Who cannot join
- a body mass index (BMI) > 30 kg/m2;
- neurological, cardiovascular, metabolic, and/or inflammatory diseases, or conditions that could be worsened by exposure to interventions and that could affect experimental variables;
- involvement in temperature manipulation program for ≥ 3 months.
Trial locations and contacts
1 site in 1 country.
About this study
Official title: The Effect of Exertional and Exogenous Heating on Physiological Markers
This study is the first to examine the effects of core temperature elevation on kynurenine pathway (KP) metabolites in healthy young males. It was hypothesized that rise in core temperature due to both pasive heating and exercise will initiate a stress response, affecting the concentration of KP metabolites. Additionally, it was expected that the exercise would produce more pronounced effects due to the increased cardiovascular, mechanical, and metabolic demands associated with it. Thus, the the main purpose of the present study was to investigate and to compare the effects of two distinct heat stress modalities on KP metabolites.
- Conditions
- Healthy Adult Male
- Being tested
- Endogenous heating, Exogenous heating
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Endogenous heatingOther
Exercise was used as the endogenous heating modality, the participant cycled at 60% of his VO2max until rectal temperature reached 39°C
Exogenous heatingOther
Hot-water immersion was used as the exogenous heating modality, where the participants sat immersed in a water bath at 43.5 ± 0.5°C and remained submerged until rectal temperature reached 39°C.
| Study group | Role | What they receive |
|---|---|---|
| Exogenous heating | Experimental | Healthy young subjects participated received exogenous heating modality, where the participants sat immersed in a water bath at 43.5 ± 0.5°C and remained submerged until rectal temperature reached 39°C. Receives: Other: Exogenous heating |
| Endogenous heating | Experimental | Healthy young subjects participated received endogenous heating modality, the participant cycled at 60% of his VO2max until rectal temperature reached 39°C Receives: Other: Endogenous heating |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in plasma metabolites of the kynurenine pathway (μm)
An ultra-performance liquid chromatography-tandem mass spectrometry system (UPLC-MS/MS) was used to measure venous plasma levels of tryptophan, kynurenine, kynurenic acid, 3-hydroxy-kynurenine, quinolinic acid, nicotinamide and picolinic acid (in μm). The UPLC-MS/MS system uses a Xevo TQ-XS triple quadrupole mass spectrometer (Waters) with a Z-spray electrospray interface, and the system operates in electrospray positive multiple reaction monitoring mode.
Measured: Day 1 (every 0.5 °C until rectal temperature (Trec) reached 39°C, followed by a recovery phase until Trec reached 37.5°C)
Rectal temperature (°C)
Rectal temperature (in °C) was measured using a thermocouple (Rectal Probe, Ellab, Denmark) inserted to a depth of 12 cm past the anal sphincter.
Measured: Day 1 (during both heating modalities until Tre reached 39°C, followed by a recovery phase until Trec reached 37.5°C)
Change in heart rate (bpm)
Heart rate (in bpm) was recorded using a heart rate sensor with a chest strap (Polar, Finland).
Measured: Day 1 (during both heating modalities until Tre reached 39°C, followed by a recovery phase until Trec reached 37.5°C)
Change in physiological strain index
A physiological strain index (PSI) was used to indicate heat strain. PSI = 5 x (Tret - Tre0) x (39.5 - Tre0)^-1+ 5 x (HRt - HR0) x (180 - HR0)^-1, where rectal temperature (Tre) t and heart rate (HR) t are simultaneous measurements taken every 0.5°C of the heat exposure and Tre0 and HR0 are the initial measurements.
Measured: Day 1 (every 0.5 °C until rectal temperature (Trec) reached 39°C, followed by a recovery phase until Trec reached 37.5°C)
Change in glucose (mmol/L)
The glucose concentration (in mmol/L) was measured using an automatic blood glucose meter Glucocard X-mini-Plus (Arkray Inc, Japan).
Measured: Day 1 (every 0.5 °C until rectal temperature (Trec) reached 39°C, followed by a recovery phase until Trec reached 37.5°C)
Change in lactate (mmol/L)
The lactate concentration (in mmol/L) was measured using an Accutrend Plus System (Roche, Germany).
Measured: Day 1 (every 0.5 °C until rectal temperature (Trec) reached 39°C, followed by a recovery phase until Trec reached 37.5°C)
Changes in prolactin concentration (ng/mL)
The venous prolactin (in ng/mL) was measured using enzyme-linked immunosorbent assay kit and a Spark multimode microplate reader (Tecan, Austria).
Measured: Day 1 (every 0.5 °C until rectal temperature (Trec) reached 39°C, followed by a recovery phase until Trec reached 37.5°C)
Changes in catecholamines concentration (ng/mL)
The venous adrenaline and noradrenaline concentrations (in ng/mL) was measured using enzyme-linked immunosorbent assay kits and a Spark multimode microplate reader (Tecan, Austria).
Measured: Day 1 (every 0.5 °C until rectal temperature (Trec) reached 39°C, followed by a recovery phase until Trec reached 37.5°C)
Changes in salivary cortisol concentration (µg/dL)
The saliva samples was collected to measure cortisol level (in µg/dL) using an ELISA kits and a Spark multimode microplate reader (Tecan, Austria).
Measured: Day 1 (every 0.5 °C until rectal temperature (Trec) reached 39°C, followed by a recovery phase until Trec reached 37.5°C)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted14 Jul 2025
- Study start11 Jan 2021
- Primary completion12 Mar 2021
- Study completion12 Mar 2021
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Healthy Adult MaleStudies 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
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Single blind
- Who is masked
- Outcomes assessor
- Enrolment
- 11 participants (actual)
Sponsor and investigators
- Lead sponsor
- Lithuanian Sports University
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07064512
- Sponsor's protocol ID
- LithuananianSportsU-24
- Status last verified
- Jul 2025
- First submitted
- 11 Jul 2025
- Last updated
- 17 Jul 2025
- Results posted
- 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 17 Jul 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- The Effect of Exertional and Exogenous Heating on Physiological Markers
- ClinicalTrials.gov ID
- NCT07064512
- Acronym / sponsor ID
- LithuananianSportsU-24
- Conditions
- Healthy Adult Male
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 11 participants (actual)
- Lead sponsor
- Lithuanian Sports UniversityUniversity, hospital or other
- Study start
- 11 Jan 2021 (actual)
- Primary completion
- 12 Mar 2021 (actual)
- Study completion
- 12 Mar 2021 (actual)
- First posted
- 14 Jul 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 the first to examine the effects of core temperature elevation on kynurenine pathway (KP) metabolites in healthy young males. It was hypothesized that rise in core temperature due to both pasive heating and exercise will initiate a stress response, affecting the concentration of KP metabolites. Additionally, it was expected that the exercise would produce more pronounced effects due to the increased cardiovascular, mechanical, and metabolic demands associated with it. Thus, the the main purpose of the present study was to investigate and to compare the effects of two distinct heat stress modalities on KP metabolites.
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Single blind (outcomes assessor)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Exogenous heating | Experimental | Other: Exogenous heatingHealthy young subjects participated received exogenous heating modality, where the participants sat immersed in a water bath at 43.5 ± 0.5°C and remained submerged until rectal temperature reached 39°C. |
| Endogenous heating | Experimental | Other: Endogenous heatingHealthy young subjects participated received endogenous heating modality, the participant cycled at 60% of his VO2max until rectal temperature reached 39°C |
Who may qualify
- Ages
- 18 to 36 years
- Sex
- Male only
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (4 listed)
- healthy adults;
- age between 18 - 36 years;
- physically active (exercising 2-3 times per week);
- non-smoking.
Key exclusion criteria (3 listed)
- a body mass index (BMI) > 30 kg/m2;
- neurological, cardiovascular, metabolic, and/or inflammatory diseases, or conditions that could be worsened by exposure to interventions and that could affect experimental variables;
- involvement in temperature manipulation program for ≥ 3 months.
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 |
|---|---|---|
| Endogenous heatingExercise was used as the endogenous heating modality, the participant cycled at 60% of his VO2max until rectal temperature reached 39°C | Other | Endogenous heating |
| Exogenous heatingHot-water immersion was used as the exogenous heating modality, where the participants sat immersed in a water bath at 43.5 ± 0.5°C and remained submerged until rectal temperature reached 39°C. | Other | Exogenous heating |
Primary outcome
Change in plasma metabolites of the kynurenine pathway (μm)
Time frame: Day 1 (every 0.5 °C until rectal temperature (Trec) reached 39°C, followed by a recovery phase until Trec reached 37.5°C)
An ultra-performance liquid chromatography-tandem mass spectrometry system (UPLC-MS/MS) was used to measure venous plasma levels of tryptophan, kynurenine, kynurenic acid, 3-hydroxy-kynurenine, quinolinic acid, nicotinamide and picolinic acid (in μm). The UPLC-MS/MS system uses a Xevo TQ-XS triple quadrupole mass spectrometer (Waters) with a Z-spray electrospray interface, and the system operates in electrospray positive multiple reaction monitoring mode.
Rectal temperature (°C)
Time frame: Day 1 (during both heating modalities until Tre reached 39°C, followed by a recovery phase until Trec reached 37.5°C)
Rectal temperature (in °C) was measured using a thermocouple (Rectal Probe, Ellab, Denmark) inserted to a depth of 12 cm past the anal sphincter.
Change in heart rate (bpm)
Time frame: Day 1 (during both heating modalities until Tre reached 39°C, followed by a recovery phase until Trec reached 37.5°C)
Heart rate (in bpm) was recorded using a heart rate sensor with a chest strap (Polar, Finland).
Change in physiological strain index
Time frame: Day 1 (every 0.5 °C until rectal temperature (Trec) reached 39°C, followed by a recovery phase until Trec reached 37.5°C)
A physiological strain index (PSI) was used to indicate heat strain. PSI = 5 x (Tret - Tre0) x (39.5 - Tre0)^-1+ 5 x (HRt - HR0) x (180 - HR0)^-1, where rectal temperature (Tre) t and heart rate (HR) t are simultaneous measurements taken every 0.5°C of the heat exposure and Tre0 and HR0 are the initial measurements.
Change in glucose (mmol/L)
Time frame: Day 1 (every 0.5 °C until rectal temperature (Trec) reached 39°C, followed by a recovery phase until Trec reached 37.5°C)
The glucose concentration (in mmol/L) was measured using an automatic blood glucose meter Glucocard X-mini-Plus (Arkray Inc, Japan).
Change in lactate (mmol/L)
Time frame: Day 1 (every 0.5 °C until rectal temperature (Trec) reached 39°C, followed by a recovery phase until Trec reached 37.5°C)
The lactate concentration (in mmol/L) was measured using an Accutrend Plus System (Roche, Germany).
Changes in prolactin concentration (ng/mL)
Time frame: Day 1 (every 0.5 °C until rectal temperature (Trec) reached 39°C, followed by a recovery phase until Trec reached 37.5°C)
The venous prolactin (in ng/mL) was measured using enzyme-linked immunosorbent assay kit and a Spark multimode microplate reader (Tecan, Austria).
Changes in catecholamines concentration (ng/mL)
Time frame: Day 1 (every 0.5 °C until rectal temperature (Trec) reached 39°C, followed by a recovery phase until Trec reached 37.5°C)
The venous adrenaline and noradrenaline concentrations (in ng/mL) was measured using enzyme-linked immunosorbent assay kits and a Spark multimode microplate reader (Tecan, Austria).
Changes in salivary cortisol concentration (µg/dL)
Time frame: Day 1 (every 0.5 °C until rectal temperature (Trec) reached 39°C, followed by a recovery phase until Trec reached 37.5°C)
The saliva samples was collected to measure cortisol level (in µg/dL) using an ELISA kits and a Spark multimode microplate reader (Tecan, Austria).
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 17 Jul 2025.
- 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 testing Endogenous heating and Exogenous heating in people with Healthy Adult Male, run by Lithuanian Sports University at 1 site in Lithuania.
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 17 Jul 2025. 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 Lithuania. 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?
Change in plasma metabolites of the kynurenine pathway (μm) (time frame: Day 1 (every 0.5 °C until rectal temperature (Trec) reached 39°C, followed by a recovery phase until Trec reached 37.5°C)). The study lists 9 primary outcomes in all. 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 17 Jul 2025.