ThermoregulationNCT05838014
Acute Sleep Deprivation on Whole-body Heat Exchange During Exercise-heat Stress in Young and Older Men
A study testing Sleep deprivation and Normal sleep in people with Thermoregulation and Sleep Disturbance, run by University of Ottawa at 1 site in Canada.
Trial summary
Sleep deprivation has long been thought to modulate thermoregulatory function. Seminal work on sleep deprivation and thermoregulation has demonstrated that sleep-deprived individuals experience greater elevations in core temperature during exercise-heat stress due to reductions in the activation of local heat loss… Read more about this study
- Who is it for?
- Ages 18 to 65 years, men onlyHealthy volunteers can take part
- Conditions the study is for
- Thermoregulation, Sleep Disturbance, Heat Exchange
- What is being tested?
- Sleep deprivation and Normal sleep
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 21 participants
- Where
- 1 siteCanada
- Study dates
- 1 Dec 2022to 29 Jun 2023
- 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 65 years
- Men only
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- healthy young (18-30 years) and older males (50-65 years)
- non-smoking
- English or French speaking
- ability to provide informed consent
Who cannot join
- presence of chronic diseases (e.g., hypertension, diabetes)
- acute illness (e.g., flu, COVID-19)
- physical restriction limiting physical activity (e.g., severe arthritis, etc.)
- use of medication judged by the patient or investigators to make participation in this study inadvisable
- engaged in regular endurance training
Trial locations and contacts
1 site in 1 country.
About this study
Official title: The Effect of Sleep Deprivation on Whole-body Heat Loss in Young and Older Men During Exercise in Hot, Dry Conditions
Sleep deprivation has long been thought to modulate thermoregulatory function. Seminal work on sleep deprivation and thermoregulation has demonstrated that sleep-deprived individuals experience greater elevations in core temperature during exercise-heat stress due to reductions in the activation of local heat loss responses of cutaneous vasodilation and sweating. However, it remains unclear 1) if reductions in local heat loss responses would compromise whole-body heat loss (evaporative + dry heat exchange) and 2) if differences exist, are they dependent on the heat load generated by exercise (increases in metabolic rate augments the rate that heat must be dissipated by the body). Further, much of the understanding of the effects of sleep deprivation on thermoregulation has been limited to assessments in young adults. Studies show that aging is associated with reduction in cutaneous vasodilation and sweating that compromise whole-body heat loss exacerbating body heat storage during moderate- and especially more vigorous-intensity exercise in the heat. However, it remains unclear if sleep deprivation may worsen this response in older adults.
The purpose of this study is therefore to evaluate the effects of sleep-deprivation on whole-body total heat loss during light, moderate, and vigorous exercise-heat stress and to assess if aging may mediate this response. To achieve this objective, direct calorimetry will be employed to measure whole-body total heat loss in young (18-30 years) and older (50-65 years) men during exercise at increasing, fixed rates of metabolic heat production of 150 (light), 200 (moderate), and 250 W/m2 (vigorous) in dry heat (40°C, ~15% relative humidity) with and without 24 hours of sleep deprivation.
- Conditions
- Thermoregulation, Sleep Disturbance, Heat Exchange, Aging, Exercise
- Being tested
- Sleep deprivation, Normal sleep
- Keywords
- Heat stress, Sleep, Aging, Heat dissipation, Physical activity
- Medical subject headings
- Parasomnias, Motor Activity, Heat Stress Disorders
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Sleep deprivationOther
Participants will undertake a period of 24 hours of total sleep deprivation prior to completing exercise
Normal sleepOther
Participants will undertake ~8 hours of normal sleep prior to completing exercise
| Study group | Role | What they receive |
|---|---|---|
| Normal sleep | Active comparator | Participants will complete three 30-minute bouts of semi-recumbent cycling at incrementally increasing fixed metabolic heat loads (150, 200 and 250 W/m2) in a hot, dry condition (40°C, 15% relative humidity). Each exercise bout will be separated by a 15 minute period of rest, with the final recovery 1 hour in duration. Exercise will commence between the hours of 7 AM and 9 AM following a period of normal sleep (~8 hours) (Control condition). Receives: Other: Normal sleep |
| Sleep deprivation | Experimental | Participants will complete three 30-minute bouts of semi-recumbent cycling at incrementally increasing fixed metabolic heat loads (150, 200 and 250 W/m2) in a hot, dry condition (40°C, 15% relative humidity). Each exercise bout will be separated by a 15 minute period of rest, with the final recovery 1 hour in duration. Exercise will commence between the hours of 7 AM and 9 AM following a period of 24 hour of sleep deprivation (Sleep deprivation condition). Receives: Other: Sleep deprivation |
What is being measured
The primary outcome is the main question the study is designed to answer.
Evaporative heat loss
Evaporative heat loss as assessed using a direct air calorimeter
Measured: End of each exercise bout (average of last 5 minutes)
Whole-body heat loss
Net heat loss (dry plus/minus evaporative heat exchange) as assessed using a direct air calorimeter
Measured: End of each exercise bout (average of last 5 minutes)
Secondary outcomes (15)
Dry heat loss
Total dry heat loss as assessed using a direct air calorimeter
Measured: End of each exercise bout (average of last 5 minutes)
Body heat storage
Change in body heat storage (i.e., amount of heat stored in the body) calculated as the temporal summation of metabolic heat production and net heat loss
Measured: Each 30 minute exercise bout and sum of all three exercise bouts
Core temperature
Rectal temperature measured as an index of core temperature
Measured: End of each exercise bout (average of last 5 minutes)
Change in core temperature
Change in rectal temperature from baseline resting
Measured: End of each exercise bout (average of last 5 minutes)
Heart rate
Measured continuously using a heart rate monitor
Measured: End of each exercise bout (average of last 5 minutes)
Heart rate reserve
Percentage of the difference between the peak heart rate
Measured: End of each exercise bout (average of last 5 minutes)
Local sweat rate (forearm, scapula)
Sweat production assessed using ventilated capsule technique
Measured: End of each exercise bout (average of last 5 minutes)
Skin temperature
Skin temperature measured continuously at 4-sites (chest, upper arm, thigh, calf) with mean value calculated as weighted value of 4 sites - bicep, 30%; chest, 30%; thigh, 20%; and calf, 20%.
Measured: End of each exercise bout (average of last 5 minutes)
Skin temperature (change)
Change in skin temperature from baseline resting as assessed at 4-sites (chest, upper arm, thigh, calf) with mean value calculated as weighted value of 4 sites - bicep, 30%; chest, 30%; thigh, 20%; and calf, 20%.
Measured: End of each exercise bout (average of last 5 minutes)
Thermal comfort scale
Thermal comfort assessed via a self-report questionnaire upon verbal prompting (4-point scale; 1: comfortable to 4: very uncomfortable)
Measured: End of the 30 minute resting baseline period, end of each 30 minute exercise bout, end of each 15 minute rest period, and 1 hour after final exercise period.
Thermal sensation
Thermal sensation assessed via a self-report questionnaire upon verbal prompting (7-point scale; 0: neutral to 7: extremely hot)
Measured: End of the 30 minute resting baseline period, end of each 30 minute exercise bout, end of each 15 minute rest period, and 1 hour after final exercise period.
Thirst sensation
Thirst sensation assessed via a self-report questionnaire upon verbal prompting (9-point scale; 1: not thirsty at all to 9: very, very thirsty)
Measured: End of the 30 minute resting baseline period, end of each 30 minute exercise bout, end of each 15 minute rest period, and 1 hour after final exercise period.
Rating of perceived exertion
Perceived exertion assessed via a self-report questionnaire upon verbal prompting (6: no exertion at all to 20: maximal exertion)
Measured: End of the 30 minute resting baseline period, end of each 30 minute exercise bout, end of each 15 minute rest period, and 1 hour after final exercise period.
Stanford sleep scale
Symptoms of tiredness assess via a self-report questionnaire upon verbal prompting (How sleepy are you?) ranging from "feeling active, vital, alert, or wide awake" to "no longer fighting sleep, sleep onset soon, having dream-like thoughts"
Measured: End of the 30 minute resting baseline period, end of each 30 minute exercise bout, end of each 15 minute rest period, and 1 hour after final exercise period.
Variables of heart rate variability
Measures of variability computed from the time, frequency, time-frequency, scale-invariant, entropy, and other nonlinear domains (R-R interval data extracted from the electrocardiogram)
Measured: End of each exercise (average of last 5 minutes)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted1 May 2023
- Study start1 Dec 2022
- Primary completion29 Jun 2023
- Study completion29 Jun 2023
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for ThermoregulationStudies 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 two exercise trials in a hot, dry environment (40°C, 15% relative humidity) where they will perform three 30 min bouts of exercise at incrementally increasing metabolic heat loads (each separated by a 15-min rest) following a period of either (i) normal sleep or (ii) 24 h of sleep deprivation.
- Masking
- None (open label)
- Enrolment
- 21 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
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05838014
- Sponsor's protocol ID
- HEPRU-2023-01
- Status last verified
- Jul 2024
- First submitted
- 30 Mar 2023
- Last updated
- 15 Jul 2024
- 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
Koetje NJ, Kirby NV, O'Connor FK, Richards BJ, Janetos KT, Ioannou LG, Kenny GP. Effect of 24-h Sleep Deprivation on Whole-Body Heat Loss in Older Males during Exercise in the Heat. Med Sci Sports Exerc. 2025 Dec 1;57(12):2715-2723. doi: 10.1249/MSS.0000000000003812. Epub 2025 Jul 7.
PubMed 40623158
Study at a glance
From the registry record, last updated by the sponsor on 15 Jul 2024. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- The Effect of Sleep Deprivation on Whole-body Heat Loss in Young and Older Men During Exercise in Hot, Dry Conditions
- ClinicalTrials.gov ID
- NCT05838014
- Acronym / sponsor ID
- HEPRU-2023-01
- Conditions
- Thermoregulation, Sleep Disturbance, Heat Exchange, Aging, Exercise
- Keywords
- Heat stress, Sleep, Aging, Heat dissipation, Physical activity
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 21 participants (actual)
- Lead sponsor
- University of OttawaUniversity, hospital or other
- Study start
- 1 Dec 2022 (actual)
- Primary completion
- 29 Jun 2023 (actual)
- Study completion
- 29 Jun 2023 (actual)
- First posted
- 1 May 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.
Sleep deprivation has long been thought to modulate thermoregulatory function. Seminal work on sleep deprivation and thermoregulation has demonstrated that sleep-deprived individuals experience greater elevations in core temperature during exercise-heat stress due to reductions in the activation of local heat loss responses of cutaneous vasodilation and sweating. However, it remains unclear 1) if reductions in local heat loss responses would compromise whole-body heat loss (evaporative + dry heat exchange) and 2) if differences exist, are they dependent on the heat load generated by exercise (increases in metabolic rate augments the rate that heat must be dissipated by the body). Further, much of the understanding of the effects of sleep deprivation on thermoregulation has been limited to assessments in young adults. Studies show that aging is associated with reduction in cutaneous vasodilation and sweating that compromise whole-body heat loss exacerbating body heat storage during moderate- and especially more vigorous-intensity exercise in the heat. However, it remains unclear if sleep deprivation may worsen this response in older adults.
The purpose of this study is therefore to evaluate the effects of sleep-deprivation on whole-body total heat loss during light, moderate, and vigorous exercise-heat stress and to assess if aging may mediate this response. To achieve this objective, direct calorimetry will be employed to measure whole-body total heat loss in young (18-30 years) and older (50-65 years) men during exercise at increasing, fixed rates of metabolic heat production of 150 (light), 200 (moderate), and 250 W/m2 (vigorous) in dry heat (40°C, ~15% relative humidity) with and without 24 hours of sleep deprivation.
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- None (open label)
- Number of arms
- 2
- Model description
- Each participant will complete two exercise trials in a hot, dry environment (40°C, 15% relative humidity) where they will perform three 30 min bouts of exercise at incrementally increasing metabolic heat loads (each separated by a 15-min rest) following a period of either (i) normal sleep or (ii) 24 h of sleep deprivation.
| Arm | Type | Receives |
|---|---|---|
| Normal sleep | Active comparator | Other: Normal sleepParticipants will complete three 30-minute bouts of semi-recumbent cycling at incrementally increasing fixed metabolic heat loads (150, 200 and 250 W/m2) in a hot, dry condition (40°C, 15% relative humidity). Each exercise bout will be separated by a 15 minute period of rest, with the final recovery 1 hour in duration. Exercise will commence between the hours of 7 AM and 9 AM following a period of normal sleep (~8 hours) (Control condition). |
| Sleep deprivation | Experimental | Other: Sleep deprivationParticipants will complete three 30-minute bouts of semi-recumbent cycling at incrementally increasing fixed metabolic heat loads (150, 200 and 250 W/m2) in a hot, dry condition (40°C, 15% relative humidity). Each exercise bout will be separated by a 15 minute period of rest, with the final recovery 1 hour in duration. Exercise will commence between the hours of 7 AM and 9 AM following a period of 24 hour of sleep deprivation (Sleep deprivation condition). |
Who may qualify
- Ages
- 18 to 65 years
- Sex
- Male only
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (4 listed)
- healthy young (18-30 years) and older males (50-65 years)
- non-smoking
- English or French speaking
- ability to provide informed consent
Key exclusion criteria (5 listed)
- presence of chronic diseases (e.g., hypertension, diabetes)
- acute illness (e.g., flu, COVID-19)
- physical restriction limiting physical activity (e.g., severe arthritis, etc.)
- use of medication judged by the patient or investigators to make participation in this study inadvisable
- engaged in regular endurance training
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 |
|---|---|---|
| Sleep deprivationParticipants will undertake a period of 24 hours of total sleep deprivation prior to completing exercise | Other | Sleep deprivation |
| Normal sleepParticipants will undertake ~8 hours of normal sleep prior to completing exercise | Other | Normal sleep |
Primary outcome
Evaporative heat loss
Time frame: End of each exercise bout (average of last 5 minutes)
Evaporative heat loss as assessed using a direct air calorimeter
Whole-body heat loss
Time frame: End of each exercise bout (average of last 5 minutes)
Net heat loss (dry plus/minus evaporative heat exchange) as assessed using a direct air calorimeter
15 secondary outcomes
Dry heat loss
Time frame: End of each exercise bout (average of last 5 minutes)
Body heat storage
Time frame: Each 30 minute exercise bout and sum of all three exercise bouts
Core temperature
Time frame: End of each exercise bout (average of last 5 minutes)
Change in core temperature
Time frame: End of each exercise bout (average of last 5 minutes)
Heart rate
Time frame: End of each exercise bout (average of last 5 minutes)
Heart rate reserve
Time frame: End of each exercise bout (average of last 5 minutes)
Local sweat rate (forearm, scapula)
Time frame: End of each exercise bout (average of last 5 minutes)
Skin temperature
Time frame: End of each exercise bout (average of last 5 minutes)
Skin temperature (change)
Time frame: End of each exercise bout (average of last 5 minutes)
Thermal comfort scale
Time frame: End of the 30 minute resting baseline period, end of each 30 minute exercise bout, end of each 15 minute rest period, and 1 hour after final exercise period.
Thermal sensation
Time frame: End of the 30 minute resting baseline period, end of each 30 minute exercise bout, end of each 15 minute rest period, and 1 hour after final exercise period.
Thirst sensation
Time frame: End of the 30 minute resting baseline period, end of each 30 minute exercise bout, end of each 15 minute rest period, and 1 hour after final exercise period.
Rating of perceived exertion
Time frame: End of the 30 minute resting baseline period, end of each 30 minute exercise bout, end of each 15 minute rest period, and 1 hour after final exercise period.
Stanford sleep scale
Time frame: End of the 30 minute resting baseline period, end of each 30 minute exercise bout, end of each 15 minute rest period, and 1 hour after final exercise period.
Variables of heart rate variability
Time frame: End of each exercise (average of last 5 minutes)
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 15 Jul 2024.
- Derived from this study: PubMed 40623158Koetje NJ, Kirby NV, O'Connor FK, Richards BJ, Janetos KT, Ioannou LG, Kenny GP. Effect of 24-h Sleep Deprivation on Whole-Body Heat Loss in Older Males during Exercise in the Heat. Med Sci Sports Exerc. 2025 Dec 1;57(12):2715-2723. doi: 10.1249/MSS.0000000000003812. Epub 2025 Jul 7.
- 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.
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 Sleep deprivation and Normal sleep in people with Thermoregulation and Sleep Disturbance, 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 4 inclusion and 5 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 15 Jul 2024. 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?
Evaporative heat loss (time frame: End of each exercise bout (average of last 5 minutes)). 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?
On the ClinicalTrials.gov record for NCT05838014, which also lists 1 linked publication.
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 15 Jul 2024.