Exploring how the human body responds to extreme heat as a result of climate change

Not Applicable

Recruiting

• Conditions: Heat-related cardiovascular strain; Heat-related thermal strain; Heat-related changes in thermal perceptions and symptoms of distress; Cardiovascular - Normal development and function of the cardiovascular system; Public Health - Other public health; Injuries and Accidents - Other injuries and accidents; Neurological - Studies of the normal brain and nervous system; Respiratory - Normal development and function of the respiratory system

• Registration Number: ACTRN12624000258550
• Lead Sponsor: The University of Sydney

Brief Summary

Not available

Detailed Description

Not available

Study Timeline

• Study Start: 2024-03-15
• Last Update Posted: 19 August 2024

Recruitment & Eligibility

• Status: Recruiting
• Sex: All
• Target Recruitment: 24

Inclusion Criteria

18-40 years old
Generally healthy
Able to read and understand English in order to provide informed consent to participate in the study

Exclusion Criteria

Those with contraindications to rectal temperature measurement (e.g., haemorrhoids, heterotopic ossification, rectal bleeding or bleeding disorder, fissures or active infections, anticoagulant therapy, colitis)
Smokers
Pregnancy
Currently diagnosed or those that possess a history of hypertension, cardiovascular, respiratory and/or metabolic disorders
Medication use related to any of the above conditions

Study & Design

• Study Type: Interventional
• Study Design: Not specified

Primary Outcome Measures

Name	Time	Method
Core temperature (Trec)[Rectal thermistor Every 5 seconds throughout the exposure for each condition];Heart rate[Bluetooth-enabled sensor and chest strap (Polar) Every 1 second throughout the exposure for each condition];Whole-body sweat loss[Mass measurements of nude body, fluid intake, and urine output assessed as individual components of a composite outcome. All masses will be assessed on digital scales. To measure the mass of fluids, a container of sufficient size and known mass will be used (e.g., water bottle, camping toilet). Body mass measurement pre- and post-exposure, and fluid and urine measurements as needed (when participant drinks water or needs to urinate) throughout the exposure for each condition]

Secondary Outcome Measures

Name	Time	Method
Mean skin temperature[Skin thermistors on the chest, shoulder, calf, and thigh assessed as individual components of a composite outcome<br> Every 5 seconds throughout the exposure for each condition<br>];Blood pressure[Automated sphygmomanometer Every 10 minutes throughout the exposure for each condition];Blood gases (pH, PO2, and PCO2)[Finger prick blood sample and point-of-care blood analyzer (i-STAT 1 and CG8+ test cartridge) Every 60 minutes throughout the exposure for each condition];Signs and symptoms of distress[Modified Environmental Symptoms Questionnaire (USARIEM, version 4) Every 20 minutes during exposures and exercise heat acclimation, with increasing frequency up to every 3 minutes if/when signs or symptoms begin to manifest];Mean skin temperature[Thermal imaging of the whole body Every 60 minutes throughout the exposure for each condition]