HyperthermiaNCT06142890
Efficacy of Ceiling Fans for Mitigating Thermal Strain During Bed Rest in Older Adults During Heat Waves
A study testing Cooling with ceiling fan in people with Hyperthermia and Heat Stress, run by University of Ottawa at 1 site in Canada.
Trial summary
With the increasing regularity and intensity of hot weather and heat waves, there is an urgent need to develop heat-alleviation strategies able to provide targeted protection for heat-vulnerable older adults. Read more about this study
- Who is it for?
- Ages 65 to 85 yearsHealthy volunteers can take part
- Conditions the study is for
- Hyperthermia, Heat Stress, Cooling
- What is being tested?
- Cooling with ceiling fan
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 20 participants
- Where
- 1 siteCanada
- Study dates
- 5 Dec 2023to 10 Feb 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 65 to 85 years
- All sexes
- Healthy volunteers accepted
- Older adult
Who may be able to join
- Male or female adults.
- Aged 65-85 years.
- Non-smoking.
- English or French speaking.
- Ability to provide informed consent.
Who cannot join
- Physical restriction (e.g., due to disease: intermittent claudication, renal impairment, active proliferative retinopathy, unstable cardiac or pulmonary disease, disabling stroke, severe arthritis, etc.).
- Use of or changes in medication judged by the patient or investigators to make participation in this study inadvisable (e.g., medications increasing risk of heat-related illness; beta blockers, anticholinergics, etc.)
- Cardiac abnormalities identified via 12-lead ECG during an incremental exercise test to volitional fatigue (performed for all participants).
- Peak aerobic capacity (VO2peak), as measured during an incremental exercise test to volitional fatigue, exceeding the 50th percentile of age- and sex-specific normative values published by the American College of Sports Medicine (ACSM).
Trial locations and contacts
1 site in 1 country.
About this study
Official title: Evaluating the Efficacy of Ceiling Fans for Limiting Heat Strain in Elderly Adults During Bed Rest in an Extreme Heat Event
With the increasing regularity and intensity of hot weather and heat waves, there is an urgent need to develop heat-alleviation strategies able to provide targeted protection for heat-vulnerable older adults. While air-conditioning provides the most effective protection from extreme heat, it is inaccessible for many individuals. Air-conditioning is also energy intensive, which can strain the electrical grid and, depending on the source of electricity generation, contribute to green house gas emissions. For these reasons, recent guidance has recommended the use of electric fans as a sustainable cooling alternative. While fans may increase sweat evaporation and heat loss in healthy, young adults, evidence supporting their use in older adults is scarce. Further, studies show that when environmental temperature exceeds skin temperature, fans are not effective and can even exacerbate hyperthermia in older adults. While older adults only account for ~13% of the population, they account for ~40% off all hospitalizations. In the context of sustainable cooling interventions, this is of particular importance given that many hospitals and long-term care homes do not have air-conditioning and rely on ceiling fans to enhance sweat evaporation while participants are bed-resting. While recent biophysical modelling has suggested that pedestal fans likely provide a clinically meaningful cooling effect (proposed to be ≥0.3°C) in temperatures below ~34°C in older adults, the efficacy of ceiling fans in mitigating heat strain in these conditions is currently unknown.
To address these knowledge gaps, this randomized crossover trial will evaluate body core temperature, cardiovascular strain, orthostatic intolerance, dehydration, and thermal comfort in adults aged 65-85 years exposed for 8-hours to conditions experienced during indoor overheating occurring during a heat wave in a temperate continental climate (31°C, 45% relative humidity). Each participant will complete two randomized exposures that will differ only in the airflow generated by a ceiling fan: no airflow (control) or standard airflow. Participants will remain in a supine position for the duration of the 8-hour exposure period, except for during hour 7 when they will complete a series of cardiovascular autonomic response tests.
- Conditions
- Hyperthermia, Heat Stress, Cooling, Aging
- Being tested
- No cooling (control), Cooling with ceiling fan
- Keywords
- Heat wave, Cooling intervention, Elderly, Thermoregulation, Cardiovascular strain, Extreme heat event
- Medical subject headings
- Hyperthermia, 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 31°C, 45% relative humidity for 8 hours without cooling intervention (control condition). Drinking water is available ad libitum. Participants remain in supine position with slight (~20°) chest and head elevation (low-Fowlers position) throughout the duration of bed-rest exposure.
Cooling with ceiling fanOther
Participants are exposed to 31°C, 45% relative humidity for 8 hours. Drinking water is available ad libitum. Participants remain in supine position with slight (~20°) chest and head elevation (low-Fowlers position) throughout the duration of bed-rest exposure. Participants will remain under a commercially available ceiling fan generating a standard air flow throughout the duration of exposure.
| Study group | Role | What they receive |
|---|---|---|
| No cooling intervention (control) | Active comparator | Adults aged 65-85 years with or without type 2 diabetes and/or hypertension Receives: Other: No cooling (control) |
| Ceiling fan generating airflow | Experimental | Adults aged 65-85 years with or without type 2 diabetes and/or hypertension Receives: Other: Cooling with ceiling fan |
What is being measured
The primary outcome is the main question the study is designed to answer.
Core temperature (peak)
Peak rectal temperature (15 min average) during exposure. Rectal temperature is measured continuously throughout each simulated heat wave.
Measured: End of heat exposure (hour 8)
Secondary outcomes (18)
Core temperature (AUC)
Area under the curve of rectal temperature (in degree-hours).
Measured: End of heat exposure (hour 8)
Core temperature (end-exposure)
Rectal temperature measured at hour 8 of the simulated heat wave exposure (15-min average)
Measured: End of heat exposure (hour 8)
Heart rate (peak)
Peak heart rate (15 min average) during exposure. Heart rate is measured continuously via 3-lead ECG throughout each simulated heat wave
Measured: End of heat exposure (hour 8)
Heart rate (end-exposure)
Heart rate measured at hour 8 of the simulated heat wave exposure (15-min average)
Measured: End of heat exposure (hour 8)
Heart rate (AUC)
Area under the curve of rectal temperature (total beats).
Measured: End of heat exposure (hour 8)
Cardiac Response to Standing From Supine (30:15 Ratio)
Cardiac response to standing evaluated as the ratio between the highest R-wave to R-wave interval (lowest heart rate) measured at the 30th heart beat after standing from supine (+/- 5 beats) and the lowest R-wave to R-wave interval (highest heart rate) measured at the 15th heart beat after standing (+/- 5 beats). Cardiac response to standing will be evaluated twice, during two lying-to-standing tests (separated by 10 min of supine rest).
Measured: During heat exposure (hour 7)
Systolic Response to Standing From Supine
Systolic blood pressure response to standing evaluated as the difference in blood pressure measured between the standing and supine. Standing systolic blood pressure will be taken as the lowest value of those measured after 60 and 120 seconds of standing. Systolic response to standing will be evaluated twice, during two lying-to-standing tests (separated by 10 min of supine rest).
Measured: During heat exposure (hour 7)
Systolic blood pressure
Systolic blood pressure measured in triplicate via automated oscillometry (~60 seconds between measures)
Measured: End of heat exposure (hour 8)
Diastolic blood pressure
Diastolic blood pressure measured in triplicate via automated oscillometry (~60 seconds between measures)
Measured: End of heat exposure (hour 8)
Rate pressure product (end-exposure)
Rate pressure product, an index of myocardial work and strain, calculated as systolic blood pressure x heart rate.
Measured: End of heat exposure (hour 8)
Heart rate variability: SDNN (end-exposure)
Standard deviation of normal-to-normal R-wave to R-wave intervals (SDNN) measured during 5 minutes of paced breathing (15 breaths/min) with participants in the seated position. SDNN will be evaluated twice, during two paced breathing periods (separated by 4 min of seated rest).
Measured: During heat exposure (hour 7)
Heart rate variability: RMSSD (end-exposure)
Root mean squared standard deviation of normal-to-normal R-wave to R-wave intervals (RMSSD) measured during 5 minutes of paced breathing (15 breaths/min) with participants in the seated position. RMSSD will be evaluated twice, during two paced breathing periods (separated by 4 min of seated rest).
Measured: During heat exposure (hour 7)
Fluid consumption
Average hourly fluid consumption calculated by weighing participant water intake at the start and end of each hour of exposure (normalized to the exposure duration).
Measured: End of heat exposure (hour 8)
Whole-body sweat rate
Average hourly whole-body sweat rate calculated as the change body mass during each exposure presented as a percentage of baseline body mass (corrected for food/water consumption and urination and normalized to the exposure duration)
Measured: End of heat exposure (hour 8)
Fluid loss
Fluid loss calculated as the change in body mass during each exposure presented as a percentage of baseline body mass (corrected for food consumption)
Measured: End of heat exposure (hour 8)
Change in plasma volume
Change in plasma volume from baseline values calculated from duplicate measurements of hemoglobin and hematocrit at the start and end of each exposure using the technique by Dill and Costill.
Measured: End of heat exposure (hour 8)
Thermal comfort scale (end-exposure)
Thermal comfort assessed via a visual analog scale ("How comfortable does your body temperature feel?") ranging from "extremely uncomfortable" to "extremely comfortable"(midpoint: neutral).
Measured: End of heat exposure (hour 8)
Orthostatic intolerance symptoms assessment
Cumulative sum of scores on 6 questions asking participant to rank symptoms associated with orthostatic intolerance during the lying to standing tests. All symptoms scored on a scale from 0 (none) to 10 (worst possible) and include feelings of: (1) "dizziness, lightheadedness, feeling faint, or feeling like you might black out"; (2) "Problems with vision (blurring, seeing spots, tunnel vision, etc.)"; (3) "Weakness"; (4) "Fatigue"; (5) "Trouble concentrating"; and (6) "Head and neck discomfort".
Measured: During heat exposure (hour 7)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted22 Nov 2023
- Study start5 Dec 2023
- Primary completion10 Feb 2024
- Study completion10 Feb 2024
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (2)Papers the sponsor has linked to this study.
- 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
- Each participant will complete 2 simulated heat wave exposures in random order: i) bed-rest; no fan cooling (control) and ii) bed-rest positioned beneath a ceiling fan providing standard air flow.
- Masking
- Double blind
- Who is masked
- Participant, Outcomes assessor
- Enrolment
- 20 participants (actual)
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 Ottawa
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06142890
- Sponsor's protocol ID
- H-11-21-7575
- Status last verified
- Feb 2025
- First submitted
- 13 Nov 2023
- Last updated
- 20 Feb 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes: Deidentified participant data will be made available with approved analysis plan and signed access agreement
Publications
McGarr GW, O'Connor FK, Kenny GP. Effects of Ceiling Fans on Self-Reported Symptoms and Mood-State in Bed-Resting Older Adults Exposed to Indoor Overheating. J Am Geriatr Soc. 2026 Jun;74(6):1703-1708. doi: 10.1111/jgs.70388. Epub 2026 Mar 15.
PubMed 41833559O'Connor FK, Meade RD, Janetos KT, Li-Maloney C, Sigal RJ, Boulay P, Kenny GP. Effect of Ceiling Fans on Core Temperature in Bed-Resting Older Adults Exposed to Indoor Overheating. J Am Geriatr Soc. 2026 Jan;74(1):200-204. doi: 10.1111/jgs.70109. Epub 2025 Sep 27.
PubMed 41014079
Study at a glance
From the registry record, last updated by the sponsor on 20 Feb 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Evaluating the Efficacy of Ceiling Fans for Limiting Heat Strain in Elderly Adults During Bed Rest in an Extreme Heat Event
- ClinicalTrials.gov ID
- NCT06142890
- Acronym / sponsor ID
- H-11-21-7575
- Conditions
- Hyperthermia, Heat Stress, Cooling, Aging
- Keywords
- Heat wave, Cooling intervention, Elderly, Thermoregulation, Cardiovascular strain, Extreme heat event
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 20 participants (actual)
- Lead sponsor
- University of OttawaUniversity, hospital or other
- Study start
- 5 Dec 2023 (actual)
- Primary completion
- 10 Feb 2024 (actual)
- Study completion
- 10 Feb 2024 (actual)
- First posted
- 22 Nov 2023 (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 regularity and intensity of hot weather and heat waves, there is an urgent need to develop heat-alleviation strategies able to provide targeted protection for heat-vulnerable older adults. While air-conditioning provides the most effective protection from extreme heat, it is inaccessible for many individuals. Air-conditioning is also energy intensive, which can strain the electrical grid and, depending on the source of electricity generation, contribute to green house gas emissions. For these reasons, recent guidance has recommended the use of electric fans as a sustainable cooling alternative. While fans may increase sweat evaporation and heat loss in healthy, young adults, evidence supporting their use in older adults is scarce. Further, studies show that when environmental temperature exceeds skin temperature, fans are not effective and can even exacerbate hyperthermia in older adults. While older adults only account for ~13% of the population, they account for ~40% off all hospitalizations. In the context of sustainable cooling interventions, this is of particular importance given that many hospitals and long-term care homes do not have air-conditioning and rely on ceiling fans to enhance sweat evaporation while participants are bed-resting. While recent biophysical modelling has suggested that pedestal fans likely provide a clinically meaningful cooling effect (proposed to be ≥0.3°C) in temperatures below ~34°C in older adults, the efficacy of ceiling fans in mitigating heat strain in these conditions is currently unknown.
To address these knowledge gaps, this randomized crossover trial will evaluate body core temperature, cardiovascular strain, orthostatic intolerance, dehydration, and thermal comfort in adults aged 65-85 years exposed for 8-hours to conditions experienced during indoor overheating occurring during a heat wave in a temperate continental climate (31°C, 45% relative humidity). Each participant will complete two randomized exposures that will differ only in the airflow generated by a ceiling fan: no airflow (control) or standard airflow. Participants will remain in a supine position for the duration of the 8-hour exposure period, except for during hour 7 when they will complete a series of cardiovascular autonomic response tests.
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Double blind (participant, outcomes assessor)
- Number of arms
- 2
- Model description
- Each participant will complete 2 simulated heat wave exposures in random order: i) bed-rest; no fan cooling (control) and ii) bed-rest positioned beneath a ceiling fan providing standard air flow.
| Arm | Type | Receives |
|---|---|---|
| No cooling intervention (control) | Active comparator | Other: No cooling (control)Adults aged 65-85 years with or without type 2 diabetes and/or hypertension |
| Ceiling fan generating airflow | Experimental | Other: Cooling with ceiling fanAdults aged 65-85 years with or without type 2 diabetes and/or hypertension |
Who may qualify
- Ages
- 65 to 85 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Older adult
Key inclusion criteria (5 listed)
- Male or female adults.
- Aged 65-85 years.
- Non-smoking.
- English or French speaking.
- Ability to provide informed consent.
Key exclusion criteria (4 listed)
- Physical restriction (e.g., due to disease: intermittent claudication, renal impairment, active proliferative retinopathy, unstable cardiac or pulmonary disease, disabling stroke, severe arthritis, etc.).
- Use of or changes in medication judged by the patient or investigators to make participation in this study inadvisable (e.g., medications increasing risk of heat-related illness; beta blockers, anticholinergics, etc.)
- Cardiac abnormalities identified via 12-lead ECG during an incremental exercise test to volitional fatigue (performed for all participants).
- Peak aerobic capacity (VO2peak), as measured during an incremental exercise test to volitional fatigue, exceeding the 50th percentile of age- and sex-specific normative values published by the American College of Sports Medicine (ACSM).
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 31°C, 45% relative humidity for 8 hours without cooling intervention (control condition). Drinking water is available ad libitum. Participants remain in supine position with slight (~20°) chest and head elevation (low-Fowlers position) throughout the duration of bed-rest exposure. | Other | No cooling intervention (control) |
| Cooling with ceiling fanParticipants are exposed to 31°C, 45% relative humidity for 8 hours. Drinking water is available ad libitum. Participants remain in supine position with slight (~20°) chest and head elevation (low-Fowlers position) throughout the duration of bed-rest exposure. Participants will remain under a commercially available ceiling fan generating a standard air flow throughout the duration of exposure. | Other | Ceiling fan generating airflow |
Primary outcome
Core temperature (peak)
Time frame: End of heat exposure (hour 8)
Peak rectal temperature (15 min average) during exposure. Rectal temperature is measured continuously throughout each simulated heat wave.
18 secondary outcomes
Core temperature (AUC)
Time frame: End of heat exposure (hour 8)
Core temperature (end-exposure)
Time frame: End of heat exposure (hour 8)
Heart rate (peak)
Time frame: End of heat exposure (hour 8)
Heart rate (end-exposure)
Time frame: End of heat exposure (hour 8)
Heart rate (AUC)
Time frame: End of heat exposure (hour 8)
Cardiac Response to Standing From Supine (30:15 Ratio)
Time frame: During heat exposure (hour 7)
Systolic Response to Standing From Supine
Time frame: During heat exposure (hour 7)
Systolic blood pressure
Time frame: End of heat exposure (hour 8)
Diastolic blood pressure
Time frame: End of heat exposure (hour 8)
Rate pressure product (end-exposure)
Time frame: End of heat exposure (hour 8)
Heart rate variability: SDNN (end-exposure)
Time frame: During heat exposure (hour 7)
Heart rate variability: RMSSD (end-exposure)
Time frame: During heat exposure (hour 7)
Fluid consumption
Time frame: End of heat exposure (hour 8)
Whole-body sweat rate
Time frame: End of heat exposure (hour 8)
Fluid loss
Time frame: End of heat exposure (hour 8)
Change in plasma volume
Time frame: End of heat exposure (hour 8)
Thermal comfort scale (end-exposure)
Time frame: End of heat exposure (hour 8)
Orthostatic intolerance symptoms assessment
Time frame: During heat exposure (hour 7)
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 20 Feb 2025.
- Derived from this study: PubMed 41833559McGarr GW, O'Connor FK, Kenny GP. Effects of Ceiling Fans on Self-Reported Symptoms and Mood-State in Bed-Resting Older Adults Exposed to Indoor Overheating. J Am Geriatr Soc. 2026 Jun;74(6):1703-1708. doi: 10.1111/jgs.70388. Epub 2026 Mar 15.
- Derived from this study: PubMed 41014079O'Connor FK, Meade RD, Janetos KT, Li-Maloney C, Sigal RJ, Boulay P, Kenny GP. Effect of Ceiling Fans on Core Temperature in Bed-Resting Older Adults Exposed to Indoor Overheating. J Am Geriatr Soc. 2026 Jan;74(1):200-204. doi: 10.1111/jgs.70109. Epub 2025 Sep 27.
- Individual participant dataSharing planned: Yes. Deidentified participant data will be made available with approved analysis plan 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
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Cooling with ceiling fan in people with Hyperthermia and Heat Stress, 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: finished, as of the sponsor's last update on 20 Feb 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 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?
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?
Core temperature (peak) (time frame: End of heat exposure (hour 8)). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT06142890, which also lists 2 linked publications.
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 20 Feb 2025.