Body Cooling in Hyperthermic Males and Females

Study Overview
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Brief Summary
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Exertional heat stroke (EHS) is an emergency medical condition that is prevalent in military soldiers, athletes, and laborers. It is diagnosed when the rectal temperature is above 40°C with the presence of central nervous dysfunction (altered mental status). The gold standard method of care for EHS is immediate onsite whole body cooling using cold-water immersion (cooling rates >0.15°C•min-1), which is reported to have the highest cooling rate. In the treatment of EHS, selecting a cooling modality with a high cooling rate becomes crucial to minimize the time above the critical threshold of body temperature at 40°C to less than 30 minutes for the best chance of survival and to minimize the severity of prognosis. However, in situations where cold water immersion is not feasible (in certain military, firefighter, or other remote settings), other cooling modalities must be available that have a cooling capacity similar to that of cold-water immersion. In this proposed study, we aim to compare the cooling rates of the Polar Breeze® (developed by Polar Breeze ®, Clearwater, FL), cold-water immersion (the current gold standard for EHS treatment), and passive cooling in individuals with exercise-induced hyperthermia

Official Title
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Efficacy of the Polar Breeze Thermal Rehabilitation Machine in Cooling Recreationally Active Males and Females Following Exercise-induced Hyperthermia

Conditions
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Cryotherapy Effect

Intervention / Treatment
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* Device: Thermal Rehabilitation Machine
* Other: Cold Water Immersion


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: males and females between the ages of 18-35. recreationally active (regularly exercise at a minimum of 4-5 times per week for greater than 30 minutes per session) Exclusion Criteria: chronic health problems fever or current illness at the time of testing history of cardiovascular, metabolic, or respiratory disease current musculoskeletal injury that limits physical activity history of exertional heat illness in the past three years

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 35 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Other
Allocation: Randomized
Intervention Model: Crossover Assignment
Interventional Model Description: Participants will complete three trials under three different body cooling conditions/interventions; passive cooling using the body's natural body cooling mechanisms, body cooling using cold water immersion, and cooling using the investigational thermal rehab machine.
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Thermal rehab machine<br>Participants, following exercise-induced hyperthermia, will be cooled using a Thermal Rehab Machine (Polar Breeze, Statim Technologies, LLC, Clearwater Florida), which is a micro-environmental air chiller. The device will be placed over the subjects head and through trans pulmonary cooling, will cool the body. | Device: Thermal Rehabilitation Machine<br>* The Polar Breeze unit is a microenvironmental air-chiller. That means it is a single-pass air-conditioner capable of cooling external air<br>* Other names: Polar Breeze;|
| Active Comparator: Cold Water Immersion<br>Participants, following exercise-induced hyperthermia, will be cooled using cold water immersion. Participants will be immersed up to their chest in cold water ( 50-55 Degrees Fahrenheit). | Other: Cold Water Immersion<br>* Whole-body immersion in cold water.<br>|
| No Intervention: Passive Cooling<br>Participants, following exercise-induced hyperthermia, will undergo a period of passive rest to allow the body to cool via natural mechanisms of evaporation of sweat from the skin's surface and convection | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in Internal Body Temperature | The rate at which body temperature is reduced during whole body cooling following exercise-induced hyperthermia. | 0, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60 minutes post onset of cooling |