Heat Acclimation and ThermotoleranceNCT06874023
Study to Warm Up and Cool Down Recreationally Active Males Using Different Protocols.
A study testing Passive heating in hot conditions, Active heating + passive heating in hot conditions and Active heating in hot conditions in people with Heat Acclimation and Thermotolerance, run by Arizona State University at 1 site in United States.
Trial summary
The objective of this study was to examine the impact of four single-bout heating and cooling strategies on warming up and cooling down core body temperature. Heating strategies included: Passive heating in a hot environment (60 min), Active heating (30 min) + passive heating (30 min) in a hot environment, Active… Read more about this study
- Who is it for?
- Ages 18 to 30 years, men only
- Conditions the study is for
- Heat Acclimation and Thermotolerance
- What is being tested?
- Passive heating in hot conditions, Active heating + passive heating in hot conditions and Active heating in hot conditions
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 10 participants
- Where
- 1 siteUnited States
- Study dates
- 14 Sep 2020to 23 Oct 2020
- 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 30 years
- Men only
- No healthy volunteers
- Adult
Who may be able to join
- self-reported healthy
- non-smoking
- uninjured
- active (training five to ten hours per week)
Who cannot join
- Participants were screened for fitness using the Physical Activity Readiness Questionnaire (PAR-Q): scoring one or more items as a yes.
- Contraindications to use a body core temperature sensor capsule.
Trial locations and contacts
1 site in 1 country.
About this study
Official title: Warm Up and Cool Down Study: Various Combined Active and Passive Isothermic Heating Protocols, Followed by Different Cooling Protocols, to Increase and Lower Body Core Temperature.
The objective of this study was to examine the impact of four single-bout heating and cooling strategies on warming up and cooling down core body temperature. Heating strategies included: Passive heating in a hot environment (60 min), Active heating (30 min) + passive heating (30 min) in a hot environment, Active heating(60 min) in a hot environment, and Active heating (60 min) at room temperature. Cooling strategies to reduce body core temperature to baseline included: Cool vest (18°C) , Damp neck towel (24°C) combined with arm (i.e. hand, forearm and half of upper arm) cool water immersion (15°C), Combination of both, A control with participant sitting in a thermoneutral room (20°C air temperature) without any additional cooling intervention.
Read the detailed description
This semi-randomized crossover control trial was performed between September and October 2020. Data collection took place over the course of 5-weeks with 10 subjects, with one data collection session with all subjects per week (hence, 40 trials total). Baseline gastrointestinal temperature (Tgi) was recorded, and the final Tgi at the end of the heating intervention (Part I), was used as the starting temperature for the current study (Part II).
Part I focused on assessing the efficacy of different heating strategies (Passive heating in a hot environment (60 min), Active heating (30 min) + passive heating (30 min) in a hot environment, Active heating(60 min) in a hot environment, and Active heating (60 min) at room temperature), aiming to reach a core temperature of 38.5°C during a 60-minute period.
Part II focused on cooling the body to a pre-exercise baseline core temperature. Cooling strategies consisted of: 1) Cool vest (18°C) with 500 mL (16 fl oz) ice water consumption, 2) Damp neck towel (24°C) combined with arm (i.e. hand, forearm and half of upper arm) cool water immersion (15°C) and 500 mL (16 fl oz) ice water consumption 3) Combination of cool vest (18°C), damp neck towel (24°C) with arm cool water immersion (15°C), and 500 mL (16 fl oz) ice water consumption or 4) A control with participant sitting in a thermoneutral room (20°C air temperature) without any additional cooling intervention. Thermoneutral water was consumed ad libitum for all interventions in addition to the 500 mL (16 fl oz) ice water consumption for experimental trials (#1-3).
- Conditions
- Heat Acclimation and Thermotolerance
- Being tested
- Passive heating in hot conditions, Active heating + passive heating in hot conditions, Active heating in hot conditions, Active heating at room temperature, Cool vest
- Keywords
- Heat, Adaptation, Passive heating
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Passive heating in hot conditionsOther
Participants performed seated passive heating in 54C conditions
Active heating + passive heating in hot conditionsOther
Participants performed 30 minutes of biking exercise in 43C + 30 min of passive seated heating in 54C conditions.
Active heating in hot conditionsOther
Participants performed 60 minutes of biking exercise in 43C.
Active heating at room temperatureOther
Participants performed active heating through biking exercise for 60 minutes at room temperature.
Cool vestOther
Cool vest (18°C) with 500 mL (16 fl oz) ice water consumption
Damp neck towel combined with arm cool water immersionOther
Damp neck towel (24°C) combined with arm (i.e. hand, forearm and half of upper arm) cool water immersion (15°C) and 500 mL (16 fl oz) ice water consumption
Combination of cooling interventionsOther
Combination of cool vest (18°C), damp neck towel (24°C) with arm cool water immersion (15°C), and 500 mL (16 fl oz) ice water consumption
Control in thermoneutral room without coolingOther
A control with participant sitting in a thermoneutral room (20°C air temperature) without any additional cooling intervention.
| Study group | Role | What they receive |
|---|---|---|
| Healthy young men exposed to heating and cooling protocols | Other | All participants underwent four times a heating protocol separated by at least one week, and during these days after undergoing the heating protocol they also participated in a protocol aiming to cool down their body temperature. Each of the four heating and cooling interventions are described as interventions. Receives: Other: Passive heating in hot conditions; Other: Active heating + passive heating in hot conditions; Other: Active heating in hot conditions; Other: Active heating at room temperature; Other: Cool vest; Other: Damp neck towel combined with arm cool water immersion; Other: Combination of cooling interventions; Other: Control in thermoneutral room without cooling |
What is being measured
The primary outcome is the main question the study is designed to answer.
Body core temperature
A portable telemetry system (E-Celsius, BodyCAP, Hérouville Saint-Clair, France) for temperature sensor capsule, with an accuracy of +/- 0.2°C, was used to measure body core temperature.
Measured: During 60 minute of heating intervention, followed by 60 minutes of cooling intervention.
Secondary outcomes (2)
Skin temperature
Wireless temperature sensors (iButton DS1+2L, Dallas Semiconductor Corp, USA), with an accuracy of ± 0.5°C and a resolution of 0.0625°C, were used to measure Tsk at 20-second intervals. Sensors at four locations (neck, right shoulder, and right shin with all 0.28 weighted coefficient, and left hand with a coefficient of 0.16 to calculate weighted Tsk outcome) as suggested per ISO protocol, held in place at the skin using Opsite transparent film (Opsite Flexigrid, Smith \& Nephew Medical Limited, Hull, England).
Measured: During 60 minute of heating intervention, followed by 60 minutes of cooling intervention.
Heart rate
Participants wore an elastic chest strap device (Bioharness-3, Zephyr Technology, Annapolis, MD, USA), measuring HR in beats per minute (bpm) at 1-second intervals.
Measured: During 60 minute of heating intervention, followed by 60 minutes of cooling intervention.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted13 Mar 2025
- Study start14 Sep 2020
- Primary completion23 Oct 2020
- Study completion23 Oct 2020
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Heat Acclimation and ThermotoleranceStudies of the same condition, open and under way.
- More trials run by Arizona State UniversityThe sponsor's other registered studies.
- 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
- Not applicable
- Intervention model
- Sequential
- Model description
- Participants performed 4 arms in non-random order (i.e. passive heating, exercise in the heat + passive heating, exercise in the heat, exercise at room temperature), followed by randomized cooling interventions (i.e. a cool slush and one of the three cooling treatments: 1) cool vest, 2) lower arm cool water immersion with cold towel in the neck, 3) combination of 1+2) or heaving no cooling intervention at room temperature with thermoneutral water only).
- Masking
- None (open label)
- Enrolment
- 10 participants (actual)
Sponsor and investigators
- Lead sponsor
- Arizona State University
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Floris Wardenaar, Arizona State University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06874023
- Sponsor's protocol ID
- STUDY00015072
- Status last verified
- Mar 2025
- First submitted
- 5 Mar 2025
- Last updated
- 13 Mar 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 13 Mar 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Warm Up and Cool Down Study: Various Combined Active and Passive Isothermic Heating Protocols, Followed by Different Cooling Protocols, to Increase and Lower Body Core Temperature.
- ClinicalTrials.gov ID
- NCT06874023
- Acronym / sponsor ID
- STUDY00015072
- Conditions
- Heat Acclimation and Thermotolerance
- Keywords
- Heat, Adaptation, Passive heating
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 10 participants (actual)
- Lead sponsor
- Arizona State UniversityUniversity, hospital or other
- Study start
- 14 Sep 2020 (actual)
- Primary completion
- 23 Oct 2020 (actual)
- Study completion
- 23 Oct 2020 (actual)
- First posted
- 13 Mar 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.
The objective of this study was to examine the impact of four single-bout heating and cooling strategies on warming up and cooling down core body temperature. Heating strategies included: Passive heating in a hot environment (60 min), Active heating (30 min) + passive heating (30 min) in a hot environment, Active heating(60 min) in a hot environment, and Active heating (60 min) at room temperature. Cooling strategies to reduce body core temperature to baseline included: Cool vest (18°C) , Damp neck towel (24°C) combined with arm (i.e. hand, forearm and half of upper arm) cool water immersion (15°C), Combination of both, A control with participant sitting in a thermoneutral room (20°C air temperature) without any additional cooling intervention.
Detailed description
This semi-randomized crossover control trial was performed between September and October 2020. Data collection took place over the course of 5-weeks with 10 subjects, with one data collection session with all subjects per week (hence, 40 trials total). Baseline gastrointestinal temperature (Tgi) was recorded, and the final Tgi at the end of the heating intervention (Part I), was used as the starting temperature for the current study (Part II).
Part I focused on assessing the efficacy of different heating strategies (Passive heating in a hot environment (60 min), Active heating (30 min) + passive heating (30 min) in a hot environment, Active heating(60 min) in a hot environment, and Active heating (60 min) at room temperature), aiming to reach a core temperature of 38.5°C during a 60-minute period.
Part II focused on cooling the body to a pre-exercise baseline core temperature. Cooling strategies consisted of: 1) Cool vest (18°C) with 500 mL (16 fl oz) ice water consumption, 2) Damp neck towel (24°C) combined with arm (i.e. hand, forearm and half of upper arm) cool water immersion (15°C) and 500 mL (16 fl oz) ice water consumption 3) Combination of cool vest (18°C), damp neck towel (24°C) with arm cool water immersion (15°C), and 500 mL (16 fl oz) ice water consumption or 4) A control with participant sitting in a thermoneutral room (20°C air temperature) without any additional cooling intervention. Thermoneutral water was consumed ad libitum for all interventions in addition to the 500 mL (16 fl oz) ice water consumption for experimental trials (#1-3).
Study design
- Primary purpose
- Other
- Allocation
- Not applicable
- Intervention model
- Sequential
- Masking
- None (open label)
- Number of arms
- 1
- Model description
- Participants performed 4 arms in non-random order (i.e. passive heating, exercise in the heat + passive heating, exercise in the heat, exercise at room temperature), followed by randomized cooling interventions (i.e. a cool slush and one of the three cooling treatments: 1) cool vest, 2) lower arm cool water immersion with cold towel in the neck, 3) combination of 1+2) or heaving no cooling intervention at room temperature with thermoneutral water only).
| Arm | Type | Receives |
|---|---|---|
| Healthy young men exposed to heating and cooling protocols | Other | Other: Passive heating in hot conditions, Other: Active heating + passive heating in hot conditions, Other: Active heating in hot conditions, Other: Active heating at room temperature, Other: Cool vest, Other: Damp neck towel combined with arm cool water immersion, Other: Combination of cooling interventions, Other: Control in thermoneutral room without coolingAll participants underwent four times a heating protocol separated by at least one week, and during these days after undergoing the heating protocol they also participated in a protocol aiming to cool down their body temperature. Each of the four heating and cooling interventions are described as interventions. |
Who may qualify
- Ages
- 18 to 30 years
- Sex
- Male only
- Healthy volunteers
- Not accepted
- Age groups
- Adult
Key inclusion criteria (4 listed)
- self-reported healthy
- non-smoking
- uninjured
- active (training five to ten hours per week)
Key exclusion criteria (2 listed)
- Participants were screened for fitness using the Physical Activity Readiness Questionnaire (PAR-Q): scoring one or more items as a yes.
- Contraindications to use a body core temperature sensor capsule.
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 |
|---|---|---|
| Passive heating in hot conditionsParticipants performed seated passive heating in 54C conditions | Other | Healthy young men exposed to heating and cooling protocols |
| Active heating + passive heating in hot conditionsParticipants performed 30 minutes of biking exercise in 43C + 30 min of passive seated heating in 54C conditions. | Other | Healthy young men exposed to heating and cooling protocols |
| Active heating in hot conditionsParticipants performed 60 minutes of biking exercise in 43C. | Other | Healthy young men exposed to heating and cooling protocols |
| Active heating at room temperatureParticipants performed active heating through biking exercise for 60 minutes at room temperature. | Other | Healthy young men exposed to heating and cooling protocols |
| Cool vestCool vest (18°C) with 500 mL (16 fl oz) ice water consumption | Other | Healthy young men exposed to heating and cooling protocols |
| Damp neck towel combined with arm cool water immersionDamp neck towel (24°C) combined with arm (i.e. hand, forearm and half of upper arm) cool water immersion (15°C) and 500 mL (16 fl oz) ice water consumption | Other | Healthy young men exposed to heating and cooling protocols |
| Combination of cooling interventionsCombination of cool vest (18°C), damp neck towel (24°C) with arm cool water immersion (15°C), and 500 mL (16 fl oz) ice water consumption | Other | Healthy young men exposed to heating and cooling protocols |
| Control in thermoneutral room without coolingA control with participant sitting in a thermoneutral room (20°C air temperature) without any additional cooling intervention. | Other | Healthy young men exposed to heating and cooling protocols |
Primary outcome
Body core temperature
Time frame: During 60 minute of heating intervention, followed by 60 minutes of cooling intervention.
A portable telemetry system (E-Celsius, BodyCAP, Hérouville Saint-Clair, France) for temperature sensor capsule, with an accuracy of +/- 0.2°C, was used to measure body core temperature.
2 secondary outcomes
Skin temperature
Time frame: During 60 minute of heating intervention, followed by 60 minutes of cooling intervention.
Heart rate
Time frame: During 60 minute of heating intervention, followed by 60 minutes of cooling intervention.
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 13 Mar 2025.
- Individual participant dataSharing planned: No
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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 Passive heating in hot conditions, Active heating + passive heating in hot conditions and Active heating in hot conditions in people with Heat Acclimation and Thermotolerance, run by Arizona State University at 1 site in United States.
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 2 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 13 Mar 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 United States. 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?
Body core temperature (time frame: During 60 minute of heating intervention, followed by 60 minutes of cooling intervention.). 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 13 Mar 2025.