HyperthermiaNCT05274009
Protective Cooling Measures to Safeguard Elderly People From Dangerous Summer Heat
A study testing Recommended cooling and Hybrid cooling in people with Hyperthermia and Heat; Weather, run by University of Ottawa at 1 site in Canada.
Trial summary
With the increasing incidence and severity of extreme heat events accompanying climate change, there is an urgent need for sustainable cooling strategies to protect heat-vulnerable older adults, who are at increased risk of adverse health events during heat stress. Read more about this study
- Who is it for?
- Ages 60 to 85 yearsHealthy volunteers can take part
- Conditions the study is for
- Hyperthermia, Heat; Weather, Aging
- What is being tested?
- Recommended cooling and Hybrid cooling
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 60 participants
- Where
- 1 siteCanada
- Study dates
- May 2023to May 2024
- 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 60 to 85 years
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- Adult aged 60-85 years
- Male or female
- Body mass index < 35 kg/m2
- For participants with type 2 diabetes: at least one year lapsed since diagnosis and hemoglobin A1c 6.0-10.5%.
- For participants with hypertension: at least one year lapsed since diagnosis or average resting blood pressure >140 systolic or >90 diastolic
Who cannot join
- Currently smoking or quit <5 years ago
- Moderate or serious medical conditions (other than Type 2 diabetes or high blood pressure), particularly those known to influence physiological responses to heat exposure (e.g., diagnosed heart disease, neurological disorders)
- Heat adapted due to repeated exposure to hot environments (use sauna, recent travel to hot climates, other)
- For participants with type 2 diabetes: "Brittle" diabetes: unpredictable hypo- \& hyperglycemia. Severe cardiovascular autonomic or peripheral neuropathy (guidelines.diabetes.ca/cpg)
Trial locations and contacts
1 site in 1 country.
Canada1 site
University of Ottawa
Ottawa, Ontario, K1N6N5
Glen P Kenny, PhD, 6135625800 ext. 4282, gkenny@uottawa.ca
Robert D Meade, PhD, 6136986071, rmead015@uottawa.ca
About this study
Official title: Evaluating the Efficacy of Cooling Centres for Limiting Heat Strain in Elderly Adults During Extreme Heat Events
With the increasing incidence and severity of extreme heat events accompanying climate change, there is an urgent need for sustainable cooling strategies to protect heat-vulnerable older adults, who are at increased risk of adverse health events during heat stress. Health agencies including the World Health Organization, the United States Centers for Disease Control and Prevention, and Health Canada currently recommend visiting a cooling centre or other air-conditioned location for 1-3 hours per day during extreme heat events to mitigate hyperthermia and strain on the cardiovascular system and therefore the risk adverse health events. However, our recent trial shows that while brief air-conditioning exposure is effective for reducing body temperature and cardiovascular burden in healthy older adults, the physiological impacts of cooling abate quickly following return to the heat. The purpose of this project is therefore to assess whether shorter but more frequent air-conditioning exposure provides more effective cooling than current recommendations (a single 1-3-hour cooling bout) in older adults with or without common chronic health conditions associated with increased vulnerability to extreme heat. This will be accomplished by evaluating physiological strain in older adults with and without diabetes and/or hypertension exposed for 8 hours to conditions reflective of extreme heat events in temperate, continental climates (35°C, 60% relative humidity). Participants will complete 3 separate simulated heat event exposures: i) a control trial (no cooling throughout the 8-hour heat event); ii) a recommended cooling trial (3 hours of heat exposure followed by 2 hours cooling); and iii) a hybrid cooling trial (2 hours of heat exposure followed by 1 hour cooling, another 2 hours heat exposure followed by 1 hour cooling, and a final 2-hour heat exposure).
- Conditions
- Hyperthermia, Heat; Weather, Aging, Type2 Diabetes, Hypertension, Heat Stress
- Being tested
- No cooling (control), Recommended cooling, Hybrid cooling
- Keywords
- Heat wave, Cooling center, Heat strain, Cardiovascular strain, Heat and health protection, Extreme heat events, Thermal comfort
- Medical subject headings
- Hyperthermia, Hypertension, Heat Stress Disorders
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
No cooling (control)Other
Participants are exposed to 35°C, 60% relative humidity for 8 hours.
Recommended coolingOther
Participants are exposed to 35°C, 60% relative humidity for 3 hours, are then moved to an air-conditioned room for 2 hours (~23°C, ~50% relative humidity), and then return to the heat for a final 3 hours.
Hybrid coolingOther
Participants are exposed to 35°C, 60% relative humidity for 2 hours, are moved to an air-conditioned room for 1 hour (~23°C, ~50% relative humidity), return to the heat for 2 hours, move back to the air-conditioned room for 1 hour, and then return to the heat for a final 2 hours
| Study group | Role | What they receive |
|---|---|---|
| Extreme heat event simulation + no cooling (control) | Experimental | Adults aged 60-85 years with or without type 2 diabetes and/or hypertension Receives: Other: No cooling (control) |
| Extreme heat event simulation + recommended cooling | Experimental | Adults aged 60-85 years with or without type 2 diabetes and/or hypertension Receives: Other: Recommended cooling |
| Extreme heat event simulation + hybrid cooling | Experimental | Adults aged 60-85 years with or without type 2 diabetes and/or hypertension Receives: Other: Hybrid cooling |
What is being measured
The primary outcome is the main question the study is designed to answer.
Core temperature (peak)
Peak rectal temperature measured during the 8-hour heat exposure.
Measured: 8-hour heat exposure
Core temperature (AUC)
Rectal temperature will be measured continuously throughout each exposure and the area under the curve will be calculated.
Measured: 8-hour heat exposure
Secondary outcomes (12)
Heart rate temperature (peak)
Peak rectal temperature measured during the 8-hour heat exposure.
Measured: 8-hour heat exposure
Heart rate (AUC)
Heart rate will be measured continuously throughout each exposure and the area under the curve will be calculated.
Measured: 8-hour heat exposure
Mean skin temperature
Mean skin temperature calculated as a weighted average of skin temperatures at 8 body regions.
Measured: Before and continuously throughout each 8 hour exposure
Arterial blood pressures
Systolic and diastolic pressures measured in triplicate.
Measured: Every hour during the 8-hour heat exposure
SDNN
Standard deviation of normal-to-normal R-R intervals measured via 3-lead ECG.
Measured: Every hour during the 8-hour heat exposure
RMSSD
Root mean squared standard deviation of normal-to-normal R-R intervals measured via 3-lead ECG.
Measured: Every hour during the 8-hour heat exposure
Rate pressure product
Rate pressure product calculated as systolic blood pressure x heart rate.
Measured: Every hour during the 8-hour heat exposure
Body fluid loss
Body fluid loss calculated as a change in body weight from pre-exposure values (corrected for food intake and deification).
Measured: Every hour during the 8-hour heat exposure
Stand test: 30:15 ratio
30:15 ratio calculated as the ratio of the RR interval measured after 30 heart beats following standing from a supine position to that measured after 15 heart beats.
Measured: Prior to and following the 8-hour heat exposure
Stand test: Systolic response to standing
Fall in systolic blood pressure after standing from a supine position.
Measured: Prior to and following the 8-hour heat exposure
Baroreflex sensitivity
Baroreflex sensitivity determined during cyclic stand-squat manoeuvres.
Measured: Prior to and following the 8-hour heat exposure
Change in plasma volume
Change in plasma volume calculated from venous blood samples (Dill and Costill technique)
Measured: Prior to and following the 8-hour heat exposure
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted10 Mar 2022
- Study startMay 2023 (estimated)
- Primary completionMay 2024 (estimated)
- Study completionMay 2024 (estimated)
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
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Model description
- Participant will complete 3 simulated extreme heat event exposures in random order: i) no cooling center intervention (control); ii) recommended cooling center intervention (1 x 2-hours of brief air-conditioning); and iii) hybrid cooling center intervention (2 x 1-hour interspersed brief air-conditioning)
- Masking
- Double blind
- Who is masked
- Participant, Outcomes assessor
- Enrolment
- 60 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University of Ottawa
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Glen P. Kenny, University of Ottawa
- Investigators
- Glen P Kenny, PhD, Principal investigator, University of OttawaRonald J Sigal, MD, MPH, Principal investigator, University of CalgaryRobert D Meade, PhD, Principal investigator, University of Ottawa
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05274009
- Sponsor's protocol ID
- H-11-21-7566
- Status last verified
- Oct 2022
- First submitted
- 25 Feb 2022
- Last updated
- 21 Oct 2022
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes: Deidentified participant data will be available from Dr. Kenny upon reasonable request and signed access agreement.
Study at a glance
From the registry record, last updated by the sponsor on 21 Oct 2022. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Evaluating the Efficacy of Cooling Centres for Limiting Heat Strain in Elderly Adults During Extreme Heat Events
- ClinicalTrials.gov ID
- NCT05274009
- Acronym / sponsor ID
- H-11-21-7566
- Conditions
- Hyperthermia, Heat; Weather, Aging, Type2 Diabetes, Hypertension, Heat Stress
- Keywords
- Heat wave, Cooling center, Heat strain, Cardiovascular strain, Heat and health protection, Extreme heat events, Thermal comfort
- Study type
- Interventional
- Recruitment status
- Unknown status
- Enrolment
- 60 participants (estimated)
- Lead sponsor
- University of OttawaUniversity, hospital or other
- Study start
- May 2023 (estimated)
- Primary completion
- May 2024 (estimated)
- Study completion
- May 2024 (estimated)
- First posted
- 10 Mar 2022 (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.
With the increasing incidence and severity of extreme heat events accompanying climate change, there is an urgent need for sustainable cooling strategies to protect heat-vulnerable older adults, who are at increased risk of adverse health events during heat stress. Health agencies including the World Health Organization, the United States Centers for Disease Control and Prevention, and Health Canada currently recommend visiting a cooling centre or other air-conditioned location for 1-3 hours per day during extreme heat events to mitigate hyperthermia and strain on the cardiovascular system and therefore the risk adverse health events. However, our recent trial shows that while brief air-conditioning exposure is effective for reducing body temperature and cardiovascular burden in healthy older adults, the physiological impacts of cooling abate quickly following return to the heat. The purpose of this project is therefore to assess whether shorter but more frequent air-conditioning exposure provides more effective cooling than current recommendations (a single 1-3-hour cooling bout) in older adults with or without common chronic health conditions associated with increased vulnerability to extreme heat. This will be accomplished by evaluating physiological strain in older adults with and without diabetes and/or hypertension exposed for 8 hours to conditions reflective of extreme heat events in temperate, continental climates (35°C, 60% relative humidity). Participants will complete 3 separate simulated heat event exposures: i) a control trial (no cooling throughout the 8-hour heat event); ii) a recommended cooling trial (3 hours of heat exposure followed by 2 hours cooling); and iii) a hybrid cooling trial (2 hours of heat exposure followed by 1 hour cooling, another 2 hours heat exposure followed by 1 hour cooling, and a final 2-hour heat exposure).
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Double blind (participant, outcomes assessor)
- Number of arms
- 3
- Model description
- Participant will complete 3 simulated extreme heat event exposures in random order: i) no cooling center intervention (control); ii) recommended cooling center intervention (1 x 2-hours of brief air-conditioning); and iii) hybrid cooling center intervention (2 x 1-hour interspersed brief air-conditioning)
| Arm | Type | Receives |
|---|---|---|
| Extreme heat event simulation + no cooling (control) | Experimental | Other: No cooling (control)Adults aged 60-85 years with or without type 2 diabetes and/or hypertension |
| Extreme heat event simulation + recommended cooling | Experimental | Other: Recommended coolingAdults aged 60-85 years with or without type 2 diabetes and/or hypertension |
| Extreme heat event simulation + hybrid cooling | Experimental | Other: Hybrid coolingAdults aged 60-85 years with or without type 2 diabetes and/or hypertension |
Who may qualify
- Ages
- 60 to 85 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (5 listed)
- Adult aged 60-85 years
- Male or female
- Body mass index < 35 kg/m2
- For participants with type 2 diabetes: at least one year lapsed since diagnosis and hemoglobin A1c 6.0-10.5%.
- For participants with hypertension: at least one year lapsed since diagnosis or average resting blood pressure >140 systolic or >90 diastolic
Key exclusion criteria (4 listed)
- Currently smoking or quit <5 years ago
- Moderate or serious medical conditions (other than Type 2 diabetes or high blood pressure), particularly those known to influence physiological responses to heat exposure (e.g., diagnosed heart disease, neurological disorders)
- Heat adapted due to repeated exposure to hot environments (use sauna, recent travel to hot climates, other)
- For participants with type 2 diabetes: "Brittle" diabetes: unpredictable hypo- \& hyperglycemia. Severe cardiovascular autonomic or peripheral neuropathy (guidelines.diabetes.ca/cpg)
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 |
|---|---|---|
| No cooling (control)Participants are exposed to 35°C, 60% relative humidity for 8 hours. | Other | Extreme heat event simulation + no cooling (control) |
| Recommended coolingParticipants are exposed to 35°C, 60% relative humidity for 3 hours, are then moved to an air-conditioned room for 2 hours (~23°C, ~50% relative humidity), and then return to the heat for a final 3 hours. | Other | Extreme heat event simulation + recommended cooling |
| Hybrid coolingParticipants are exposed to 35°C, 60% relative humidity for 2 hours, are moved to an air-conditioned room for 1 hour (~23°C, ~50% relative humidity), return to the heat for 2 hours, move back to the air-conditioned room for 1 hour, and then return to the heat for a final 2 hours | Other | Extreme heat event simulation + hybrid cooling |
Primary outcome
Core temperature (peak)
Time frame: 8-hour heat exposure
Peak rectal temperature measured during the 8-hour heat exposure.
Core temperature (AUC)
Time frame: 8-hour heat exposure
Rectal temperature will be measured continuously throughout each exposure and the area under the curve will be calculated.
12 secondary outcomes
Heart rate temperature (peak)
Time frame: 8-hour heat exposure
Heart rate (AUC)
Time frame: 8-hour heat exposure
Mean skin temperature
Time frame: Before and continuously throughout each 8 hour exposure
Arterial blood pressures
Time frame: Every hour during the 8-hour heat exposure
SDNN
Time frame: Every hour during the 8-hour heat exposure
RMSSD
Time frame: Every hour during the 8-hour heat exposure
Rate pressure product
Time frame: Every hour during the 8-hour heat exposure
Body fluid loss
Time frame: Every hour during the 8-hour heat exposure
Stand test: 30:15 ratio
Time frame: Prior to and following the 8-hour heat exposure
Stand test: Systolic response to standing
Time frame: Prior to and following the 8-hour heat exposure
Baroreflex sensitivity
Time frame: Prior to and following the 8-hour heat exposure
Change in plasma volume
Time frame: Prior to and following the 8-hour heat exposure
Results and safety
Results are not available in the source record.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 21 Oct 2022.
- Individual participant dataSharing planned: Yes. Deidentified participant data will be available from Dr. Kenny upon reasonable request and signed access agreement.
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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.
Glen P Kenny, PhD principal investigator
University of Ottawa
Ronald J Sigal, MD, MPH principal investigator
University of Calgary
Robert D Meade, PhD principal investigator
University of Ottawa
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Recommended cooling and Hybrid cooling in people with Hyperthermia and Heat; Weather, run by University of Ottawa at 1 site in Canada.
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 5 inclusion and 4 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: status not confirmed, as of the sponsor's last update on 21 Oct 2022. 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 Canada. 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?
Results are not available in the source record.
How can a doctor refer a patient or contact the research team?
Contact Glen P Kenny, PhD (6135625800 ext. 4282, gkenny@uottawa.ca), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Core temperature (peak) (time frame: 8-hour heat exposure). The study lists 2 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 21 Oct 2022.