HyperthermiaPYTHONNCT04715711
Physiological and Thermoregulatory Responses of Body Cooling During Cycling in a Hot Environment
A study testing Forearm coolng, Wet-towel cooling and mist-fan in people with Hyperthermia, run by University of Connecticut at 1 site in United States.
Trial summary
BHSAI is developing a computational system that provides early alerts of a rise in core body temperature to help reduce the risk of heat injury in the field and during training. The goal of the body temperature alerting system is to use it during rest, exercise in the heat and during body cooling. Read more about this study
- Who is it for?
- Ages 18 to 28 years, men onlyHealthy volunteers can take part
- Conditions the study is for
- Hyperthermia
- What is being tested?
- Forearm coolng, Wet-towel cooling and mist-fan
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 12 participants
- Where
- 1 siteUnited States
- Study dates
- 2 Apr 2021to 19 Jul 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 28 years
- Men only
- Healthy volunteers accepted
- Adult
Who may be able to join
- Cisgender man between the ages of 18-28 years
- been cleared by the medical monitor for this study
- VO2max > 45ml/kg/min
- Aerobically active (at least 30 minutes of aerobic exercise 4-5 days per week)
Who cannot join
- Have a current musculoskeletal injury that would limit their physical activity or preclude the participant from walking, jogging, running, sprinting, or cutting.
- Chronic health problems that affect your ability to thermoregulate (disorders affecting the liver, kidneys or the ability to sweat normally)
- Fever or current illness at the time of testing
- History of cardiovascular, metabolic, or respiratory disease
- A family member died for no apparent reason, had a heart attack, died from heart problems, or sudden death before the age of 50
- Current musculoskeletal injury that limits their physical activity
Show all 11Show fewer
- Currently taking a medication that is known to influence body temperature (amphetamines, antihypertensives, anticholinergics, acetaminophen, diuretics, NSAIDs, aspirin)
- Identify as cisgender woman, transgender man or transgender woman. Cisgender women, Transgender men, and transgender women are excluded from the current study because the sponsor of the study has requested that this testing be done in physically active cisgender males. It is assumed that they either currently have data on women or transgender women/men to compare this to or have a strategic initiative from a marketing or business perspective that only involves cisgender men.
- Have a history of heat related illness
- Throat or gastroesophageal diseases including gastroesophageal reflux disease (aka, GERD) or difficulty swallowing
- Have any allergies or adverse reactions to the cold (e.g. Cold Uticaria, Raynauds Phenomenon/Disease, or Cryoglobulinanemia)
Trial locations and contacts
1 site in 1 country.
United States1 site
Korey Stringer Institute, University of Connecticut
Storrs, Connecticut, 06269
About this study
Official title: Physiological and Thermoregulatory Responses of Body Cooling During Cycling in a Hot Environment (PYTHON)
BHSAI is developing a computational system that provides early alerts of a rise in core body temperature to help reduce the risk of heat injury in the field and during training. The goal of the body temperature alerting system is to use it during rest, exercise in the heat and during body cooling. Using this system during cooling will allow healthcare professionals and military personnel monitor core temperature to ensure cooling is effective (and prevent hypothermia). Therefore, the primary purpose of this investigation is to validate a body temperature alerting system using physiological responses that occur during rest, exercise in the heat and during body cooling. Multiple cooling modalities will be validated. This study is expanding on a previous intervention IRB#H20-0010 (BHSAI Cooling Study), but will examine body cooling during more intense exercise and while cycling. We will also examine the effectiveness of each cooling modality (passive cooling, mist-fan cooling, hand/forearm immersion, ice towel) on physiological variables after exercise in the heat.
Read the detailed description
Design
The study will be completed in the following timeline:
Visit 1: Baseline and VO2max Testing
Vist 2: Metabolic Heat Production Visit
Visit 3-6: Trial 1, 2 ,3, 4
Visit specific information is described below, however, specific data collection protocols for dependent variables and procedures are included below the description of the study design. Participants will be asked to sign a photo/video release form (Appendix H) to be used in research projects, scientific publications/conferences and for educational purposes. Participants may be videoed or photographed while exercising or resting in the environmental chamber. Participants will be assigned after medical clearance is granted.
Visit 1: Baseline and VO2max Testing
Participants who are approved to participate will be scheduled for a baseline and VO2max testing day. Basal metabolic rate (BMR) will be measured upon arrival during the baseline visit. The participant will lay supine with a ventilated hood covering their head and torso. The ventilated hood will be attached to a hose connected to a metabolic cart. The metabolic cart will continuously measure respiratory exchange ratio, oxygen consumption, and substrate utilization. The participant will remain under the hood for approximately 30 minutes. Upon completion of BMR, participants will provide a urine sample in a clean urine cup. Urine specific gravity and urine color will be assessed. Nude body mass will also be recorded. Privacy will be afforded for each participant while obtaining body mass measures by taking measurements with the participant alone in a private room behind a solid, closed door, and the research reading the scale outside of the room. Participants will only be permitted to continue to the VO2max test if the euhydrated criteria of a urine specific gravity (USG) ≤1.025 is met. If the participant arrives with a USG between 1.020 and 1.025, the subject will be asked to drink 500 mL of water to ensure proper hydration status. If USG is greater than 1.025 the subject will be rescheduled for a different day. Height will be measured with a tape measure on Visit 1. Percent body fat will be measured using Air displacement plethysmography (BodPod®; Cosmed, Software Version 4.2+, Concord, CA, USA). This will take less than ~5 minutes to complete. This information will be used to describe the subject demographics. Participants will also be asked to complete a maximal oxygen uptake (VO2max) test on a treadmill and on a cycle ergometer in a thermoneutral environment with about 30 minutes to one hour between. This test will provide aerobic fitness levels of the participants which will be compared between the two exercise protocols. Participants will also be asked about their average weekly physical activity (Appendix K). This visit will take approximately 1-2 hours.
Visit 2: Metabolic Heat Production Visit
In order to prescribe appropriate exercise intensity, heat production must be controlled. Heat production will be prescribed utilizing a graded exercise test (3-5 minute stages) in the heat (same environmental temperature as trials) that will measure metabolic data via collection of expired air utilizing 2-way non-rebreathing mask in order to calculate heat production and appropriately choose cycling intensities to compare between groups of research participants. This test will occur following the baseline visit. The study procedures will mimic those of trials (described below), with the exception of the exercise protocol. The exercise protocol will take approximately 20 minutes to complete. It will include 5 stages of exercise (graded stages). The participant will wear the ACU during this visit.
Visit 3-6: Trials 1-4
Participant numbers will be randomly assigned, and 4 trials (mist-fan, forearm, passive cooling, ice towel) will be ordered with a random number generator and assigned to a participant number.
These orders will be counterbalanced between participants to ensure that there is not an order effect. Each participant will complete four trials as part of the study. Participants will be allowed to make-up trial visits if they are sick, suffer an injury or do not meet hydration requirements. Participants will be asked if they have a current illness or taking medications to determine whether they can complete the exercise trial. The participant's visit will be rescheduled if they have a fever, current illness or taking medications that influence body temperature. Participants will complete four trials on four separate days.
Trial #
Cooling Intervention
1
Passive Cooling
2
Mist-fan Cooling
3
Forearm Immersion
4
Ice Towel
The exercise protocol and recovery portions of this study will be conducted in a climatic chamber with ambient temperature approximately 30-40°C and relative humidity at approximately 30-70%. Participants will drink ad libitum throughout the exercise trial.
Upon arrival to the lab, participants will be asked to indicate if they have consumed alcohol or caffeine in the last 24 hours and 12 hours, respectively. They will not be asked to specify exactly what they have consumed, but if they provide a positive indication, their trial will be rescheduled for another day. Participants will provide a small urine sample in a clean urine cup, and a nude body mass will be measured. Upon arrival to the lab, hydration status will be assessed by urine specific gravity, nude body mass and urine color. Participants will only be permitted to continue to the exercise trial if the euhydrated criteria of a urine specific gravity (USG) ≤1.025 is met. If the participant arrives with a USG between 1.020 and 1.025, the subject will be asked to drink 500 mL of water to ensure proper hydration status. If USG is greater than 1.025 then the subject will be rescheduled for a different day. Participants will be given instructions at the prior visit about how to obtain desired hydration status for the upcoming trial. Researchers will insert an esophageal probe. Only trained personnel are permitted to insert the esophageal probe (no undergraduates will be allowed). Participants will insert a rectal probe and wear a heart rate monitor strap. Additionally, participants will wear 9-site Biopac skin temperature sensors. Researchers will apply the skin temperature sensors with medical tape to the participants' chest, upper arm, forearm, thigh, neck, abdomen, thigh, back, and calf (anterior and posterior). Participants will also wear iButtons (wireless skin temperature sensors) on their chest, upper arm, forearm, thigh, and calf (anterior and posterior). The participants will also be asked to complete a subjective sleep questionnaire upon arriving to the lab. Participants will wear an active combat uniform (ACU) during the exercise trials. Three ADU sizes for the blouse and pants (small, medium, large) will be available for the participants. A belt will be used to ensure the ACU fits appropriately. Participants will not be able to keep the ACU- ADUs will be washed (according to manufacturer's instructions) and re-used for participants. ADU manufacturer's instructions is identical to standard washing cycle (detergent and washing machine dry). The ACU will be weighed before and after use to measure sweat captured in the clothing. Participants will wear the wrist-based devices (provided by BHSAI) on their non-dominant arm throughout the testing. The wrist device must be placed approximately 1-inch proximal to the wrist and be fitted snugly for accurate heart-rate measurements. The wrist device is used to estimate heart rate using infrared technology. The wrist device estimates of heart rate will be compared to the polar heart rate monitor (gold standard). The body alerting system uses heart rate from the wrist device and the environmental conditions to estimate body temperature. The sponsor of the study will use rectal temperature and the 7-site skin temperature sensors to alter the algorithm (not in real time- from the collected data) to better estimate body temperature. The future goal is to have the body alerting system imbedded in the watch. Participants will wear another wrist-based device (WHOOP) on the arm that does not have the BHSAI device. The WHOOP device will monitor heart rate variability and sleep. Participants will be asked to wear this device daily for the duration of the study.
Participants will enter the environmental chamber and sit for 30 minutes to become equilibrated. The environmental chamber will be set to 30-40°C ambient temperature, 30-70% relative humidity After baseline measures of heart rate, rectal temperature, participants will complete the perceptual indices. Participants will also complete an environmental symptoms questionnaire (ESQ).
The trial will consist of two 40-minute intervals of cycling from 7W/kg to 15 W/kg. Each 40-minute exercise block will be followed by a rest break where cooling will occur. Participants will be allowed to drink ad libitum throughout the exercise trial. The participant will be cooled for approximately 30 minutes with their assigned cooling modality. Rectal and esophageal temperature, skin temperature, heart rate, perceptual measures, and mood (POMS, described below) will be collected at various time points before, during, and after exercise and cooling. Metabolic heat production will be measured using indirect calorimetry (mask connected to metabolic cart) during all four trials.
Passive Cooling: Participants will be asked to sit in a chair in the climate chamber for passive cooling.
Mist-fan cooling: A mist-fan will be placed next to the participant and will mist-fan only their hands and forearms during mist-fan cooling. Participants will be asked to roll up their ADU sleeves to increase skin surface area. The temperature of the mist and wind speed of the fan will be recorded.
Forearm immersion: The participant will place their forearm in approximately 20°C water during forearm immersion.
Ice Towel: a towel that can hold water for extended periods will be used and submerged in an ice-water mixture (~2 C). Researchers will gently squeeze the towel to remove excess water (but remain saturated with water) and then apply to both forearms and hands snuggly so that there is no air gap between the towel and the extremity. Apply for 1-5 minutes and then replace it with another fresh, cold towel. This step would ensure that the forearms and hands have near about constant application temperature as the towel would get warm over the application period. The process will be repeated for the entire cooling duration.
Data collection will be divided into two separate phases. A pilot study will be first conducted in which the first two participants will complete all study laboratory visits. Data from those trials will be shared with the sponsor for review before continuation of data collection. Participants will undergo the same procedures for the pilot testing as regular testing. Pilot testing data will be included in the dataset. Following approval from the sponsor, data collection will resume. Each trial will be approximately 4 hours.
All devices will be properly cleaned according to manufacturer's instruction prior to use by other participants.
- Conditions
- Hyperthermia
- Being tested
- Forearm coolng, Wet-towel cooling, mist-fan, passive cooling
- Medical subject headings
- Hyperthermia
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Forearm coolngOther
forearm immersion will be performed for active cooling assessment
Wet-towel coolingOther
Wet towels will be wrapped around the participant's arms for active cooling
mist-fanOther
a mist-fan will be placed in front of the participant for active cooling
passive coolingOther
participants will sit in a chair and "passively cool" (no active intervention)
| Study group | Role | What they receive |
|---|---|---|
| Active Cooling | Active comparator | Participants will be actively cooled during rest breaks Receives: Other: Forearm coolng; Other: Wet-towel cooling; Other: mist-fan |
| No Intervention | Placebo comparator | Participants will participant in "passive cooling" where they sit in a chair during rest. Receives: Other: passive cooling |
What is being measured
The primary outcome is the main question the study is designed to answer.
Difference in VO2max between Cycle ergometer and treadmill
Participants will be fitted with a Hans Rudolph mask attached to a breathing tube to measure the expired air delivered to the metabolic cart system during the exercise protocol. The metabolic cart will continuously measure oxygen consumption (VO2) to asess their VO2max value.
Measured: At the end of exercise test for both cycle ergometer and treadmill
Metabolic Heat Production
Participants will be tested for 3-5 minutes at different % of their VO2max. It will include 5 stages.
Measured: Will be measured continuously throughout the 25 min exercise protocol.
Change in Rectal Temperature
Rectal thermometer will be self-inserted by participant to assess core temperature
Measured: Measured continuously during two, 40 min exercise blocks and 2 20-30 min cooling periods.
Change in Esophageal Temperature
Esophageal thermometer will be inserted by a researcher to assess core temperature
Measured: Measured continuously during two, 40 min exercise blocks and 2 20-30 min cooling periods
Change in Heart Rate
A heart rate monitor will be worn by participant throughout exercise/cooling protocol
Measured: Measured continuously during two, 40 min exercise blocks and 2 20-30 min cooling periods
Change in Mean Skin temperature
Prior to the start of exercise, participants will be instrumented with 9-site (Biopac) and 6-site skin temperature (iButton) sensors. The Biopac skin temperature sensors will be placed on the chest, shoulder, forearm, abdomen, neck, back, thigh and anterior calf and posterior calf. and the iButton skin temperature sensors will be placed on the chest, arm, thigh, and anterior calf and posterior calf.
Measured: Measured continuously during two, 40 min exercise blocks and 2 20-30 min cooling periods
Change in Rating of Perceived Exertion
6-20 scale that indicates how hard the participant feels they are working. 6 represents rest and 20 represents maximal exertion. A high score indicates more perceived exertion.
Measured: Every 10 minutes of the exercise blocks (2 x 40 mins) and cooling period (2 x 20-30 min)
Secondary outcomes (3)
Change in Thermal Sensation
0-8 Scale (cold to hot) that indicated how cold or hot the participate feels. 0 = extremely cold, 8 = extremely hot.
Measured: Every 10 minutes of the exercise blocks (2 x 40 mins) and cooling period (2 x 20-30 min)
Change in Perception of Fatigue
0-10 (no fatigue to extreme fatigue) Scale that indicates how fatigued the participate feels. High score indicates more fatigue (negative outcome).
Measured: Every 10 minutes of the exercise blocks (2 x 40 mins) and cooling period (2 x 20-30 min)
Change in Perception of thirst
0-9 (no thirst to extreme thirst) Scale that indicates how thirsty the subject feels. A higher score is considered a negative outcome.
Measured: Every 10 minutes of the exercise blocks (2 x 40 mins) and cooling period (2 x 20-30 min)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted20 Jan 2021
- Study start2 Apr 2021
- Primary completion19 Jul 2021
- Study completion19 Jul 2021
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for HyperthermiaStudies 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
- Participants received four cooling treatments on separate study visits: 1) passive cooling 2) forearm cooling 3) mist-fan cooling, 4) ice towel coolng
- Masking
- None (open label)
- Enrolment
- 12 participants (actual)
Sponsor and investigators
- Lead sponsor
- University of Connecticut
- Sponsor type
- University, hospital or other
- Collaborators
- BHSAI
- Responsible party
- Principal investigator, Douglas J Casa, University of Connecticut
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT04715711
- Sponsor's protocol ID
- H20-0168
- Acronym
- PYTHON
- Status last verified
- Aug 2021
- First submitted
- 14 Jan 2021
- Last updated
- 3 Aug 2021
- 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 3 Aug 2021. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Physiological and Thermoregulatory Responses of Body Cooling During Cycling in a Hot Environment (PYTHON)
- ClinicalTrials.gov ID
- NCT04715711
- Acronym / sponsor ID
- PYTHON / H20-0168
- Conditions
- Hyperthermia
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 12 participants (actual)
- Lead sponsor
- University of ConnecticutUniversity, hospital or other
- Collaborators
- BHSAI
- Study start
- 2 Apr 2021 (actual)
- Primary completion
- 19 Jul 2021 (actual)
- Study completion
- 19 Jul 2021 (actual)
- First posted
- 20 Jan 2021 (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.
BHSAI is developing a computational system that provides early alerts of a rise in core body temperature to help reduce the risk of heat injury in the field and during training. The goal of the body temperature alerting system is to use it during rest, exercise in the heat and during body cooling. Using this system during cooling will allow healthcare professionals and military personnel monitor core temperature to ensure cooling is effective (and prevent hypothermia). Therefore, the primary purpose of this investigation is to validate a body temperature alerting system using physiological responses that occur during rest, exercise in the heat and during body cooling. Multiple cooling modalities will be validated. This study is expanding on a previous intervention IRB#H20-0010 (BHSAI Cooling Study), but will examine body cooling during more intense exercise and while cycling. We will also examine the effectiveness of each cooling modality (passive cooling, mist-fan cooling, hand/forearm immersion, ice towel) on physiological variables after exercise in the heat.
Detailed description
Design
The study will be completed in the following timeline:
Visit 1: Baseline and VO2max Testing
Vist 2: Metabolic Heat Production Visit
Visit 3-6: Trial 1, 2 ,3, 4
Visit specific information is described below, however, specific data collection protocols for dependent variables and procedures are included below the description of the study design. Participants will be asked to sign a photo/video release form (Appendix H) to be used in research projects, scientific publications/conferences and for educational purposes. Participants may be videoed or photographed while exercising or resting in the environmental chamber. Participants will be assigned after medical clearance is granted.
Visit 1: Baseline and VO2max Testing
Participants who are approved to participate will be scheduled for a baseline and VO2max testing day. Basal metabolic rate (BMR) will be measured upon arrival during the baseline visit. The participant will lay supine with a ventilated hood covering their head and torso. The ventilated hood will be attached to a hose connected to a metabolic cart. The metabolic cart will continuously measure respiratory exchange ratio, oxygen consumption, and substrate utilization. The participant will remain under the hood for approximately 30 minutes. Upon completion of BMR, participants will provide a urine sample in a clean urine cup. Urine specific gravity and urine color will be assessed. Nude body mass will also be recorded. Privacy will be afforded for each participant while obtaining body mass measures by taking measurements with the participant alone in a private room behind a solid, closed door, and the research reading the scale outside of the room. Participants will only be permitted to continue to the VO2max test if the euhydrated criteria of a urine specific gravity (USG) ≤1.025 is met. If the participant arrives with a USG between 1.020 and 1.025, the subject will be asked to drink 500 mL of water to ensure proper hydration status. If USG is greater than 1.025 the subject will be rescheduled for a different day. Height will be measured with a tape measure on Visit 1. Percent body fat will be measured using Air displacement plethysmography (BodPod®; Cosmed, Software Version 4.2+, Concord, CA, USA). This will take less than ~5 minutes to complete. This information will be used to describe the subject demographics. Participants will also be asked to complete a maximal oxygen uptake (VO2max) test on a treadmill and on a cycle ergometer in a thermoneutral environment with about 30 minutes to one hour between. This test will provide aerobic fitness levels of the participants which will be compared between the two exercise protocols. Participants will also be asked about their average weekly physical activity (Appendix K). This visit will take approximately 1-2 hours.
Visit 2: Metabolic Heat Production Visit
In order to prescribe appropriate exercise intensity, heat production must be controlled. Heat production will be prescribed utilizing a graded exercise test (3-5 minute stages) in the heat (same environmental temperature as trials) that will measure metabolic data via collection of expired air utilizing 2-way non-rebreathing mask in order to calculate heat production and appropriately choose cycling intensities to compare between groups of research participants. This test will occur following the baseline visit. The study procedures will mimic those of trials (described below), with the exception of the exercise protocol. The exercise protocol will take approximately 20 minutes to complete. It will include 5 stages of exercise (graded stages). The participant will wear the ACU during this visit.
Visit 3-6: Trials 1-4
Participant numbers will be randomly assigned, and 4 trials (mist-fan, forearm, passive cooling, ice towel) will be ordered with a random number generator and assigned to a participant number.
These orders will be counterbalanced between participants to ensure that there is not an order effect. Each participant will complete four trials as part of the study. Participants will be allowed to make-up trial visits if they are sick, suffer an injury or do not meet hydration requirements. Participants will be asked if they have a current illness or taking medications to determine whether they can complete the exercise trial. The participant's visit will be rescheduled if they have a fever, current illness or taking medications that influence body temperature. Participants will complete four trials on four separate days.
Trial #
Cooling Intervention
1
Passive Cooling
2
Mist-fan Cooling
3
Forearm Immersion
4
Ice Towel
The exercise protocol and recovery portions of this study will be conducted in a climatic chamber with ambient temperature approximately 30-40°C and relative humidity at approximately 30-70%. Participants will drink ad libitum throughout the exercise trial.
Upon arrival to the lab, participants will be asked to indicate if they have consumed alcohol or caffeine in the last 24 hours and 12 hours, respectively. They will not be asked to specify exactly what they have consumed, but if they provide a positive indication, their trial will be rescheduled for another day. Participants will provide a small urine sample in a clean urine cup, and a nude body mass will be measured. Upon arrival to the lab, hydration status will be assessed by urine specific gravity, nude body mass and urine color. Participants will only be permitted to continue to the exercise trial if the euhydrated criteria of a urine specific gravity (USG) ≤1.025 is met. If the participant arrives with a USG between 1.020 and 1.025, the subject will be asked to drink 500 mL of water to ensure proper hydration status. If USG is greater than 1.025 then the subject will be rescheduled for a different day. Participants will be given instructions at the prior visit about how to obtain desired hydration status for the upcoming trial. Researchers will insert an esophageal probe. Only trained personnel are permitted to insert the esophageal probe (no undergraduates will be allowed). Participants will insert a rectal probe and wear a heart rate monitor strap. Additionally, participants will wear 9-site Biopac skin temperature sensors. Researchers will apply the skin temperature sensors with medical tape to the participants' chest, upper arm, forearm, thigh, neck, abdomen, thigh, back, and calf (anterior and posterior). Participants will also wear iButtons (wireless skin temperature sensors) on their chest, upper arm, forearm, thigh, and calf (anterior and posterior). The participants will also be asked to complete a subjective sleep questionnaire upon arriving to the lab. Participants will wear an active combat uniform (ACU) during the exercise trials. Three ADU sizes for the blouse and pants (small, medium, large) will be available for the participants. A belt will be used to ensure the ACU fits appropriately. Participants will not be able to keep the ACU- ADUs will be washed (according to manufacturer's instructions) and re-used for participants. ADU manufacturer's instructions is identical to standard washing cycle (detergent and washing machine dry). The ACU will be weighed before and after use to measure sweat captured in the clothing. Participants will wear the wrist-based devices (provided by BHSAI) on their non-dominant arm throughout the testing. The wrist device must be placed approximately 1-inch proximal to the wrist and be fitted snugly for accurate heart-rate measurements. The wrist device is used to estimate heart rate using infrared technology. The wrist device estimates of heart rate will be compared to the polar heart rate monitor (gold standard). The body alerting system uses heart rate from the wrist device and the environmental conditions to estimate body temperature. The sponsor of the study will use rectal temperature and the 7-site skin temperature sensors to alter the algorithm (not in real time- from the collected data) to better estimate body temperature. The future goal is to have the body alerting system imbedded in the watch. Participants will wear another wrist-based device (WHOOP) on the arm that does not have the BHSAI device. The WHOOP device will monitor heart rate variability and sleep. Participants will be asked to wear this device daily for the duration of the study.
Participants will enter the environmental chamber and sit for 30 minutes to become equilibrated. The environmental chamber will be set to 30-40°C ambient temperature, 30-70% relative humidity After baseline measures of heart rate, rectal temperature, participants will complete the perceptual indices. Participants will also complete an environmental symptoms questionnaire (ESQ).
The trial will consist of two 40-minute intervals of cycling from 7W/kg to 15 W/kg. Each 40-minute exercise block will be followed by a rest break where cooling will occur. Participants will be allowed to drink ad libitum throughout the exercise trial. The participant will be cooled for approximately 30 minutes with their assigned cooling modality. Rectal and esophageal temperature, skin temperature, heart rate, perceptual measures, and mood (POMS, described below) will be collected at various time points before, during, and after exercise and cooling. Metabolic heat production will be measured using indirect calorimetry (mask connected to metabolic cart) during all four trials.
Passive Cooling: Participants will be asked to sit in a chair in the climate chamber for passive cooling.
Mist-fan cooling: A mist-fan will be placed next to the participant and will mist-fan only their hands and forearms during mist-fan cooling. Participants will be asked to roll up their ADU sleeves to increase skin surface area. The temperature of the mist and wind speed of the fan will be recorded.
Forearm immersion: The participant will place their forearm in approximately 20°C water during forearm immersion.
Ice Towel: a towel that can hold water for extended periods will be used and submerged in an ice-water mixture (~2 C). Researchers will gently squeeze the towel to remove excess water (but remain saturated with water) and then apply to both forearms and hands snuggly so that there is no air gap between the towel and the extremity. Apply for 1-5 minutes and then replace it with another fresh, cold towel. This step would ensure that the forearms and hands have near about constant application temperature as the towel would get warm over the application period. The process will be repeated for the entire cooling duration.
Data collection will be divided into two separate phases. A pilot study will be first conducted in which the first two participants will complete all study laboratory visits. Data from those trials will be shared with the sponsor for review before continuation of data collection. Participants will undergo the same procedures for the pilot testing as regular testing. Pilot testing data will be included in the dataset. Following approval from the sponsor, data collection will resume. Each trial will be approximately 4 hours.
All devices will be properly cleaned according to manufacturer's instruction prior to use by other participants.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- None (open label)
- Number of arms
- 2
- Model description
- Participants received four cooling treatments on separate study visits: 1) passive cooling 2) forearm cooling 3) mist-fan cooling, 4) ice towel coolng
| Arm | Type | Receives |
|---|---|---|
| Active Cooling | Active comparator | Other: Forearm coolng, Other: Wet-towel cooling, Other: mist-fanParticipants will be actively cooled during rest breaks |
| No Intervention | Placebo comparator | Other: passive coolingParticipants will participant in "passive cooling" where they sit in a chair during rest. |
Who may qualify
- Ages
- 18 to 28 years
- Sex
- Male only
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (4 listed)
- Cisgender man between the ages of 18-28 years
- been cleared by the medical monitor for this study
- VO2max > 45ml/kg/min
- Aerobically active (at least 30 minutes of aerobic exercise 4-5 days per week)
Key exclusion criteria (11 listed)
- Have a current musculoskeletal injury that would limit their physical activity or preclude the participant from walking, jogging, running, sprinting, or cutting.
- Chronic health problems that affect your ability to thermoregulate (disorders affecting the liver, kidneys or the ability to sweat normally)
- Fever or current illness at the time of testing
- History of cardiovascular, metabolic, or respiratory disease
- A family member died for no apparent reason, had a heart attack, died from heart problems, or sudden death before the age of 50
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 |
|---|---|---|
| Forearm coolngforearm immersion will be performed for active cooling assessment | Other | Active Cooling |
| Wet-towel coolingWet towels will be wrapped around the participant's arms for active cooling | Other | Active Cooling |
| mist-fana mist-fan will be placed in front of the participant for active cooling | Other | Active Cooling |
| passive coolingparticipants will sit in a chair and "passively cool" (no active intervention) | Other | No Intervention |
Primary outcome
Difference in VO2max between Cycle ergometer and treadmill
Time frame: At the end of exercise test for both cycle ergometer and treadmill
Participants will be fitted with a Hans Rudolph mask attached to a breathing tube to measure the expired air delivered to the metabolic cart system during the exercise protocol. The metabolic cart will continuously measure oxygen consumption (VO2) to asess their VO2max value.
Metabolic Heat Production
Time frame: Will be measured continuously throughout the 25 min exercise protocol.
Participants will be tested for 3-5 minutes at different % of their VO2max. It will include 5 stages.
Change in Rectal Temperature
Time frame: Measured continuously during two, 40 min exercise blocks and 2 20-30 min cooling periods.
Rectal thermometer will be self-inserted by participant to assess core temperature
Change in Esophageal Temperature
Time frame: Measured continuously during two, 40 min exercise blocks and 2 20-30 min cooling periods
Esophageal thermometer will be inserted by a researcher to assess core temperature
Change in Heart Rate
Time frame: Measured continuously during two, 40 min exercise blocks and 2 20-30 min cooling periods
A heart rate monitor will be worn by participant throughout exercise/cooling protocol
Change in Mean Skin temperature
Time frame: Measured continuously during two, 40 min exercise blocks and 2 20-30 min cooling periods
Prior to the start of exercise, participants will be instrumented with 9-site (Biopac) and 6-site skin temperature (iButton) sensors. The Biopac skin temperature sensors will be placed on the chest, shoulder, forearm, abdomen, neck, back, thigh and anterior calf and posterior calf. and the iButton skin temperature sensors will be placed on the chest, arm, thigh, and anterior calf and posterior calf.
Change in Rating of Perceived Exertion
Time frame: Every 10 minutes of the exercise blocks (2 x 40 mins) and cooling period (2 x 20-30 min)
6-20 scale that indicates how hard the participant feels they are working. 6 represents rest and 20 represents maximal exertion. A high score indicates more perceived exertion.
3 secondary outcomes
Change in Thermal Sensation
Time frame: Every 10 minutes of the exercise blocks (2 x 40 mins) and cooling period (2 x 20-30 min)
Change in Perception of Fatigue
Time frame: Every 10 minutes of the exercise blocks (2 x 40 mins) and cooling period (2 x 20-30 min)
Change in Perception of thirst
Time frame: Every 10 minutes of the exercise blocks (2 x 40 mins) and cooling period (2 x 20-30 min)
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 3 Aug 2021.
- 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 Forearm coolng, Wet-towel cooling and mist-fan in people with Hyperthermia, run by University of Connecticut 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 11 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 3 Aug 2021. 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. Some participants in this study may receive a placebo. 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?
Difference in VO2max between Cycle ergometer and treadmill (time frame: At the end of exercise test for both cycle ergometer and treadmill). The study lists 7 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 3 Aug 2021.