AgingNCT05618197
Chronic Passive Heating in Healthy Older Adults
A study testing Passive heating in people with Aging, run by University of Portsmouth at 1 site in United Kingdom.
Trial summary
Aging is associated with a decline in cardiovascular health, cognitive function and losses in muscle strength, with half or more of those over age 65 suffering from two or more comorbidities (e.g., heart disease, type 2 diabetes). Read more about this study
- Who is it for?
- Ages 55 years and olderHealthy volunteers can take part
- Conditions the study is for
- Aging
- What is being tested?
- Passive heating
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 19 participants
- Where
- 1 siteUnited Kingdom
- Study dates
- 23 May 2023to 6 Jun 2025
- 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 55 years and older
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- Male or female age ≥ 55
- Free from cardiometabolic disease
- Body mass index of 18-35 kg/m2
- Receipt of a normal 12-lead ECG approved by the School Independent Medical Officer
- Capacity to understand and provide their written, informed consent to participate in the study protocol
Who cannot join
- Unable to understand or cooperate with the study protocol due to learning difficulties or otherwise
- Any current, or past medical (last five years), history of any cardiovascular, respiratory, cancer, renal, hepatic, gastrointestinal, haematological, lymphatic, neurological, psychiatric, or any other disease or diseases.
- Any regular medication for the last five years (not including acute courses of treatment of less than one month for discrete, resolved conditions).
- Medications that may influence physiological responses to the passive heating intervention Uncontrolled hypertension (≥ 150 mmHg systolic and/or ≥ 90 mmHg diastolic)
- Body mass index of > 35 kg/m2
- Recent long-term exposure to a hot climate (within the previous three months)
- Current smoker (or have stopped smoking within the previous three months)
Trial locations and contacts
1 site in 1 country.
About this study
Official title: The Effects of Chronic Passive Heating on Vascular Function, Cognitive Function, Muscle Function and Heat Shock Protein Responses in Middle-aged to Older Adults: A Randomised, Controlled Crossover Trial
Aging is associated with a decline in cardiovascular health, cognitive function and losses in muscle strength, with half or more of those over age 65 suffering from two or more comorbidities (e.g., heart disease, type 2 diabetes). The worldwide population of older adults is growing rapidly, with one in six people expected to be over age 65 by 2050. This will place further financial burden from chronic diseases on already stressed healthcare systems. While studies show that frequent exercise is an effective way for older adults to maintain or improve cardiovascular and metabolic health, older individuals are less physically active and do not adhere well to exercise programs, often due to physical or medical limitations. Therefore, alternative methods for older adults to get the same health benefits as exercise require further exploration. Recent work has shown that passive heat therapy may be one such alternative solution.
Read the detailed description
Aging is associated with declines in cardiovascular health and cognitive function as well as chronic inflammation and the development of neurodegenerative conditions such as Alzheimer's and Parkinson's disease. Additionally, ageing results in a loss of muscle size and strength, commonly referred to as sarcopenia, leading to increased risk of falls or adverse exercise-related events. It is well understood that frequent exercise improves cardiovascular and metabolic health whilst lowering the risk of disease and all-cause mortality, acting as a treatment for many different health conditions. Despite the evidence of its efficacy, many individuals struggle with adherence to exercise programmes, particularly older adults and clinical populations, with many individuals within these populations unable to perform exercise due to physical limitations or medical contraindications. With one in six people expected to be over the age of 65 years by 2050 and corresponding increases in non-communicable diseases (e.g., cancer, diabetes, cardiovascular disease) anticipated from this aging population, the development of adjunct treatments or alternatives to exercise to improve general health in older populations is needed.
Recent work has shown that a potential solution could be the use of passive heat therapy (PHT) (e.g., hot water immersion, sauna), which can achieve health benefits comparable to exercise. Previous work by Brunt and colleagues using eight weeks of chronic heat therapy has demonstrated systemic macro- and microvascular adaptations in young, healthy individuals including improved endothelial function, reduced arterial stiffness and cutaneous vascular conductance. Chronic passive heat acclimation in young, healthy adults has also been shown to improve working memory. Additional studies have shown that ten weeks of passive heating improved muscle strength in middle-aged men and ten days of daily pulsed shortwave diathermy attenuated immobilization-induced muscle atrophy in young, healthy adults.
One potential mechanism for the physiological benefits obtained from PHT is the increase of cytoprotective heat shock proteins (HSP) (specifically HSP27, HSP60, HSP70 and HSP90) intracellularly (i) and extracellularly (e) in response to increases in deep body temperature. Increases in the expression of these HSPs have been shown to play a role in reducing inflammation and protecting the vasculature via increases in endothelial nitric oxide synthase activity. Increased HSP concentrations may also prevent the accumulation of harmful biomarkers in the brain that play a role in cognitive decline and development of neurodegenerative diseases. Aging, however, is associated with a reduction in HSP transcription activity in various tissues, resulting in an impaired heat shock response and development of a pro-inflammatory state. Previous work using acute hot water immersion has shown increases in eHSP70. The only study to test the effects of chronic hot water immersion on resting iHSP70 showed no effect, however, the magnitude of stimulus (39°C water) applied by Hoekstra and colleagues and the resultant changes in core temperature were likely too low to induce any changes in HSPs.
These studies provide promising evidence that health benefits from PHT similar to those from exercise could translate to older adults. However, most studies testing the effects of PHT on humans have been performed in young, healthy adults, whereas older individuals are likely to derive the greatest benefit from any positive effects of PHT. To date, no study has examined the longer-term effects of PHT on macrovascular, microvascular, cognitive or muscle function, or HSPs in older adults. Therefore, further research is needed to confirm that heat therapy confers the same beneficial health adaptations in older adults.
- Conditions
- Aging
- Being tested
- Passive heating
- Keywords
- Passive heating, Endothelial function, Heat shock proteins, Cognitive function, Muscle strength
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Passive heatingOther
~3x per week of 1 h hot water immersion (to the clavicle, @40°C, rectal temperature ~38.5°C and <39°C) sessions over a period of 6 weeks.
| Study group | Role | What they receive |
|---|---|---|
| Passive heating intervention | Experimental | ~3x per week of 1 h hot water immersion (to the clavicle, @40°C, rectal temperature ~38.5°C and <39°C) sessions over a period of 6 weeks. Receives: Other: Passive heating |
| Control | No intervention | 6 weeks of no hot water immersion |
What is being measured
The primary outcome is the main question the study is designed to answer.
Brachial artery flow-mediated dilation
Percentage change from baseline in brachial artery diameter assessed by ultrasound.
Measured: Pre and post 6 weeks of passive heating and pre and post 6 weeks no intervention with 6 weeks washout between arms
Secondary outcomes (33)
Brachial and carotid artery blood flow velocity
Change from baseline in blood flow velocity of the brachial artery and right common carotid artery as assessed via ultrasound. cm/s is the unit.
Measured: Pre and post 6 weeks of passive heating and pre and post 6 weeks no intervention with 6 weeks washout between arms
Carotid vessel diameter
Change from baseline in vessel diameter of the right common carotid artery as assessed via ultrasound. mm is the unit.
Measured: Pre and post 6 weeks of passive heating and pre and post 6 weeks no intervention with 6 weeks washout between arms
Carotid intima-media thickness
Change from baseline in intima-media thickness of the right common carotid artery as assessed via ultrasound. mm is the unit
Measured: Pre and post 6 weeks of passive heating and pre and post 6 weeks no intervention with 6 weeks washout between arms
Carotid compliance
Change in compliance of the right common carotid artery and return to baseline as assessed via ultrasound. µm^2 per kilopascal is the unit.
Measured: Pre and post 6 weeks of passive heating and pre and post 6 weeks no intervention with 6 weeks washout between arms
Carotid distensibility
Change in distensibility of the right common carotid artery and return to baseline as assessed via ultrasound. 10^-3/kPa is the unit.
Measured: Pre and post 6 weeks of passive heating and pre and post 6 weeks no intervention with 6 weeks washout between arms
Carotid stiffness
Change in stiffness of the right common carotid artery and return to baseline as assessed via ultrasound. Meters per second is the unit.
Measured: Pre and post 6 weeks of passive heating and pre and post 6 weeks no intervention with 6 weeks washout between arms
Microvascular function
Change from baseline in microvascular function as assessed via iontophoresis on the forearm with acetylcholine (ACh) and Insulin, Area under the curve is the unit.
Measured: Pre and post 6 weeks of passive heating and pre and post 6 weeks no intervention with 6 weeks washout between arms
Stroke volume
Change from baseline in stroke volume measured noninvasively via thoracic impedance. mL/m^2 is the unit
Measured: Pre and post 6 weeks of passive heating and pre and post 6 weeks no intervention with 6 weeks washout between arms
Total peripheral resistance
Change from baseline in total peripheral resistance measured noninvasively via thoracic impedance.
Measured: Pre and post 6 weeks of passive heating and pre and post 6 weeks no intervention with 6 weeks washout between arms
Cardiac output
Change from baseline in cardiac output measured noninvasively via thoracic impedance. L/min is the unit.
Measured: Pre and post 6 weeks of passive heating and pre and post 6 weeks no intervention with 6 weeks washout between arms
Mean arterial pressure
Change from baseline in resting mean arterial pressure. mmHg is the unit.
Measured: Pre and post 6 weeks of passive heating and pre and post 6 weeks no intervention with 6 weeks washout between arms
Systolic blood pressure
Change from baseline in resting systolic blood pressure. mmHg is the unit.
Measured: Pre and post 6 weeks of passive heating and pre and post 6 weeks no intervention with 6 weeks washout between arms
Diastolic blood pressure
Change from baseline in resting diastolic blood pressure. mmHg is the unit.
Measured: Pre and post 6 weeks of passive heating and pre and post 6 weeks no intervention with 6 weeks washout between arms
Intracellular HSP27 concentration
Change from baseline in resting iHSP27 concentrations? Measured via immunoblotting in peripheral blood mononuclear cells (PBMCs).
Measured: Pre and post 6 weeks of passive heating and pre and post 6 weeks no intervention with 6 weeks washout between arms
Intracellular HSP60 concentration
Change from baseline in resting iHSP60 concentrations? Measured via immunoblotting in peripheral blood mononuclear cells (PBMCs).
Measured: Pre and post 6 weeks of passive heating and pre and post 6 weeks no intervention with 6 weeks washout between arms
Intracellular HSP70 concentration
Change from baseline in resting iHSP70 concentrations? Measured via immunoblotting in peripheral blood mononuclear cells (PBMCs).
Measured: Pre and post 6 weeks of passive heating and pre and post 6 weeks no intervention with 6 weeks washout between arms
Intracellular HSP90 concentration
Change from baseline in resting iHSP90 concentrations? Measured via immunoblotting in peripheral blood mononuclear cells (PBMCs).
Measured: Pre and post 6 weeks of passive heating and pre and post 6 weeks no intervention with 6 weeks washout between arms
Plasma eHSP27 concentration
Change from baseline in resting plasma eHSP27 concentrations? Measured via ELISA
Measured: Pre and post 6 weeks of passive heating and pre and post 6 weeks no intervention with 6 weeks washout between arms
Plasma eHSP60 concentration
Change from baseline in resting plasma eHSP60 concentrations? Measured via ELISA.
Measured: Pre and post 6 weeks of passive heating and pre and post 6 weeks no intervention with 6 weeks washout between arms
Plasma eHSP70 concentration
Change from baseline in resting plasma eHSP70 concentrations? Measured via ELISA.
Measured: Pre and post 6 weeks of passive heating and pre and post 6 weeks no intervention with 6 weeks washout between arms
Plasma eHSP90 concentration
Change from baseline in resting plasma eHSP90 concentrations? Measured via ELISA.
Measured: Pre and post 6 weeks of passive heating and pre and post 6 weeks no intervention with 6 weeks washout between arms
Reaction time
Change in reaction time in response to a heating challenge. Assessed using ANAM: Automated Neurophysiological Assessment Metrics.
Measured: Pre and post 6 weeks of the passive heating intervention during the first and final heating visits at time points of pre-hot water immersion, 0 hours post and 3 hours post hot water immersion
Logical reasoning
Change in logical reasoning in response to a heating challenge. Assessed using ANAM: Automated Neurophysiological Assessment Metrics.
Measured: Pre and post 6 weeks of the passive heating intervention during the first and final heating visits at time points of pre-hot water immersion, 0 hours post and 3 hours post hot water immersion
Memory
Change in memory in response to a heating challenge. Assessed using ANAM: Automated Neurophysiological Assessment Metrics.
Measured: Pre and post 6 weeks of the passive heating intervention during the first and final heating visits at time points of pre-hot water immersion, 0 hours post and 3 hours post hot water immersion
Cerebral oxygenation
Change in cerebral oxygenation in response to a heating challenge. Assessed using Near-infrared spectroscopy (NIRS) attached to the forehead.
Measured: Pre and post 6 weeks of the passive heating intervention during the first and final heating visits at time points of pre-hot water immersion, 0 hours post and 3 hours post hot water immersion
Maximum quadriceps strength
Change from baseline in quadriceps strength. Assessed using an isokinetic dynamometer.
Measured: Pre and post 6 weeks of passive heating and pre and post 6 weeks no intervention with 6 weeks washout between arms
Maximum grip strength
Change from baseline in grip strength. Assessed using a hand grip dynamometer.
Measured: Pre and post 6 weeks of passive heating and pre and post 6 weeks no intervention with 6 weeks washout between arms
Lower extremity function
Change from baseline in lower extremity function. Assessed using the Short Physical Performance Battery (balance, walking speed and sit to stand) .
Measured: Pre and post 6 weeks of passive heating and pre and post 6 weeks no intervention with 6 weeks washout between arms
Quadriceps muscle electrical activity
Change from baseline in quadriceps muscle electrical activity. Assessed using electromyography (EMG) on the vastus lateralis of the dominant leg.
Measured: Pre and post 6 weeks of passive heating and pre and post 6 weeks no intervention with 6 weeks washout between arms
Balance capacity
Does chronic passive heating improve balance? Assessed using motion capture and force plates.
Measured: Pre and post 6 weeks of passive heating and pre and post 6 weeks no intervention with 6 weeks washout between arms
Gait characteristics
Change from baseline in gait characteristics. Assessed using motion capture and force plates.
Measured: Pre and post 6 weeks of passive heating and pre and post 6 weeks no intervention with 6 weeks washout between arms
Total minutes of physical activity (light, moderate, moderate to vigorous physical activity).
Change from baseline in physical activity levels. Assessed using wrist-worn accelerometry.
Measured: Pre and during the final week of 6 weeks of passive heating and pre and during the final week of 6 weeks no intervention with 6 weeks washout between arms
Sleep efficiency (time in bed + time asleep)
Change from baseline in sleep efficiency. Assessed using wrist-worn accelerometry.
Measured: Pre and during the final week of 6 weeks of passive heating and pre and during the final week of 6 weeks no intervention with 6 weeks washout between arms
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted16 Nov 2022
- Study start23 May 2023
- Primary completion6 Jun 2025
- Study completion6 Jun 2025
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 AgingStudies 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
- Treatment
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- None (open label)
- Enrolment
- 19 participants (actual)
Sponsor and investigators
- Lead sponsor
- University of Portsmouth
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Ant Shepherd, University of Portsmouth
- Investigators
- Zoe Saynor, PhD, Study director, University of Portsmouth
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05618197
- Sponsor's protocol ID
- UoPCPHHOA
- Status last verified
- Mar 2025
- First submitted
- 8 Nov 2022
- Last updated
- 6 Aug 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
Publications
Piccolo DD, Corbett J, Exell TA, Moore JM, Wright A, Alnajjar MGA, Hudson LC, Marsh PA, Praskacova V, McNarry MA, Mackintosh KA, Saynor ZL, Shepherd AI. Effect of repeated hot water immersion on muscle strength, power, function and physical activity in healthy older adults: A randomised crossover trial. Exp Physiol. 2026 Apr 20:10.1113/EP093501. doi: 10.1113/EP093501. Online ahead of print.
PubMed 42010888
Study at a glance
From the registry record, last updated by the sponsor on 6 Aug 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- The Effects of Chronic Passive Heating on Vascular Function, Cognitive Function, Muscle Function and Heat Shock Protein Responses in Middle-aged to Older Adults: A Randomised, Controlled Crossover Trial
- ClinicalTrials.gov ID
- NCT05618197
- Acronym / sponsor ID
- UoPCPHHOA
- Conditions
- Aging
- Keywords
- Passive heating, Endothelial function, Heat shock proteins, Cognitive function, Muscle strength
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 19 participants (actual)
- Lead sponsor
- University of PortsmouthUniversity, hospital or other
- Study start
- 23 May 2023 (actual)
- Primary completion
- 6 Jun 2025 (actual)
- Study completion
- 6 Jun 2025 (actual)
- First posted
- 16 Nov 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.
Aging is associated with a decline in cardiovascular health, cognitive function and losses in muscle strength, with half or more of those over age 65 suffering from two or more comorbidities (e.g., heart disease, type 2 diabetes). The worldwide population of older adults is growing rapidly, with one in six people expected to be over age 65 by 2050. This will place further financial burden from chronic diseases on already stressed healthcare systems. While studies show that frequent exercise is an effective way for older adults to maintain or improve cardiovascular and metabolic health, older individuals are less physically active and do not adhere well to exercise programs, often due to physical or medical limitations. Therefore, alternative methods for older adults to get the same health benefits as exercise require further exploration. Recent work has shown that passive heat therapy may be one such alternative solution.
Detailed description
Aging is associated with declines in cardiovascular health and cognitive function as well as chronic inflammation and the development of neurodegenerative conditions such as Alzheimer's and Parkinson's disease. Additionally, ageing results in a loss of muscle size and strength, commonly referred to as sarcopenia, leading to increased risk of falls or adverse exercise-related events. It is well understood that frequent exercise improves cardiovascular and metabolic health whilst lowering the risk of disease and all-cause mortality, acting as a treatment for many different health conditions. Despite the evidence of its efficacy, many individuals struggle with adherence to exercise programmes, particularly older adults and clinical populations, with many individuals within these populations unable to perform exercise due to physical limitations or medical contraindications. With one in six people expected to be over the age of 65 years by 2050 and corresponding increases in non-communicable diseases (e.g., cancer, diabetes, cardiovascular disease) anticipated from this aging population, the development of adjunct treatments or alternatives to exercise to improve general health in older populations is needed.
Recent work has shown that a potential solution could be the use of passive heat therapy (PHT) (e.g., hot water immersion, sauna), which can achieve health benefits comparable to exercise. Previous work by Brunt and colleagues using eight weeks of chronic heat therapy has demonstrated systemic macro- and microvascular adaptations in young, healthy individuals including improved endothelial function, reduced arterial stiffness and cutaneous vascular conductance. Chronic passive heat acclimation in young, healthy adults has also been shown to improve working memory. Additional studies have shown that ten weeks of passive heating improved muscle strength in middle-aged men and ten days of daily pulsed shortwave diathermy attenuated immobilization-induced muscle atrophy in young, healthy adults.
One potential mechanism for the physiological benefits obtained from PHT is the increase of cytoprotective heat shock proteins (HSP) (specifically HSP27, HSP60, HSP70 and HSP90) intracellularly (i) and extracellularly (e) in response to increases in deep body temperature. Increases in the expression of these HSPs have been shown to play a role in reducing inflammation and protecting the vasculature via increases in endothelial nitric oxide synthase activity. Increased HSP concentrations may also prevent the accumulation of harmful biomarkers in the brain that play a role in cognitive decline and development of neurodegenerative diseases. Aging, however, is associated with a reduction in HSP transcription activity in various tissues, resulting in an impaired heat shock response and development of a pro-inflammatory state. Previous work using acute hot water immersion has shown increases in eHSP70. The only study to test the effects of chronic hot water immersion on resting iHSP70 showed no effect, however, the magnitude of stimulus (39°C water) applied by Hoekstra and colleagues and the resultant changes in core temperature were likely too low to induce any changes in HSPs.
These studies provide promising evidence that health benefits from PHT similar to those from exercise could translate to older adults. However, most studies testing the effects of PHT on humans have been performed in young, healthy adults, whereas older individuals are likely to derive the greatest benefit from any positive effects of PHT. To date, no study has examined the longer-term effects of PHT on macrovascular, microvascular, cognitive or muscle function, or HSPs in older adults. Therefore, further research is needed to confirm that heat therapy confers the same beneficial health adaptations in older adults.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- None (open label)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Passive heating intervention | Experimental | Other: Passive heating~3x per week of 1 h hot water immersion (to the clavicle, @40°C, rectal temperature ~38.5°C and <39°C) sessions over a period of 6 weeks. |
| Control | No intervention | –6 weeks of no hot water immersion |
Who may qualify
- Ages
- 55 years and older
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (5 listed)
- Male or female age ≥ 55
- Free from cardiometabolic disease
- Body mass index of 18-35 kg/m2
- Receipt of a normal 12-lead ECG approved by the School Independent Medical Officer
- Capacity to understand and provide their written, informed consent to participate in the study protocol
Key exclusion criteria (7 listed)
- Unable to understand or cooperate with the study protocol due to learning difficulties or otherwise
- Any current, or past medical (last five years), history of any cardiovascular, respiratory, cancer, renal, hepatic, gastrointestinal, haematological, lymphatic, neurological, psychiatric, or any other disease or diseases.
- Any regular medication for the last five years (not including acute courses of treatment of less than one month for discrete, resolved conditions).
- Medications that may influence physiological responses to the passive heating intervention Uncontrolled hypertension (≥ 150 mmHg systolic and/or ≥ 90 mmHg diastolic)
- Body mass index of > 35 kg/m2
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 |
|---|---|---|
| Passive heating~3x per week of 1 h hot water immersion (to the clavicle, @40°C, rectal temperature ~38.5°C and <39°C) sessions over a period of 6 weeks. | Other | Passive heating intervention |
Primary outcome
Brachial artery flow-mediated dilation
Time frame: Pre and post 6 weeks of passive heating and pre and post 6 weeks no intervention with 6 weeks washout between arms
Percentage change from baseline in brachial artery diameter assessed by ultrasound.
33 secondary outcomes
Brachial and carotid artery blood flow velocity
Time frame: Pre and post 6 weeks of passive heating and pre and post 6 weeks no intervention with 6 weeks washout between arms
Carotid vessel diameter
Time frame: Pre and post 6 weeks of passive heating and pre and post 6 weeks no intervention with 6 weeks washout between arms
Carotid intima-media thickness
Time frame: Pre and post 6 weeks of passive heating and pre and post 6 weeks no intervention with 6 weeks washout between arms
Carotid compliance
Time frame: Pre and post 6 weeks of passive heating and pre and post 6 weeks no intervention with 6 weeks washout between arms
Carotid distensibility
Time frame: Pre and post 6 weeks of passive heating and pre and post 6 weeks no intervention with 6 weeks washout between arms
Carotid stiffness
Time frame: Pre and post 6 weeks of passive heating and pre and post 6 weeks no intervention with 6 weeks washout between arms
Microvascular function
Time frame: Pre and post 6 weeks of passive heating and pre and post 6 weeks no intervention with 6 weeks washout between arms
Stroke volume
Time frame: Pre and post 6 weeks of passive heating and pre and post 6 weeks no intervention with 6 weeks washout between arms
Total peripheral resistance
Time frame: Pre and post 6 weeks of passive heating and pre and post 6 weeks no intervention with 6 weeks washout between arms
Cardiac output
Time frame: Pre and post 6 weeks of passive heating and pre and post 6 weeks no intervention with 6 weeks washout between arms
Mean arterial pressure
Time frame: Pre and post 6 weeks of passive heating and pre and post 6 weeks no intervention with 6 weeks washout between arms
Systolic blood pressure
Time frame: Pre and post 6 weeks of passive heating and pre and post 6 weeks no intervention with 6 weeks washout between arms
Diastolic blood pressure
Time frame: Pre and post 6 weeks of passive heating and pre and post 6 weeks no intervention with 6 weeks washout between arms
Intracellular HSP27 concentration
Time frame: Pre and post 6 weeks of passive heating and pre and post 6 weeks no intervention with 6 weeks washout between arms
Intracellular HSP60 concentration
Time frame: Pre and post 6 weeks of passive heating and pre and post 6 weeks no intervention with 6 weeks washout between arms
Intracellular HSP70 concentration
Time frame: Pre and post 6 weeks of passive heating and pre and post 6 weeks no intervention with 6 weeks washout between arms
Intracellular HSP90 concentration
Time frame: Pre and post 6 weeks of passive heating and pre and post 6 weeks no intervention with 6 weeks washout between arms
Plasma eHSP27 concentration
Time frame: Pre and post 6 weeks of passive heating and pre and post 6 weeks no intervention with 6 weeks washout between arms
Plasma eHSP60 concentration
Time frame: Pre and post 6 weeks of passive heating and pre and post 6 weeks no intervention with 6 weeks washout between arms
Plasma eHSP70 concentration
Time frame: Pre and post 6 weeks of passive heating and pre and post 6 weeks no intervention with 6 weeks washout between arms
Plasma eHSP90 concentration
Time frame: Pre and post 6 weeks of passive heating and pre and post 6 weeks no intervention with 6 weeks washout between arms
Reaction time
Time frame: Pre and post 6 weeks of the passive heating intervention during the first and final heating visits at time points of pre-hot water immersion, 0 hours post and 3 hours post hot water immersion
Logical reasoning
Time frame: Pre and post 6 weeks of the passive heating intervention during the first and final heating visits at time points of pre-hot water immersion, 0 hours post and 3 hours post hot water immersion
Memory
Time frame: Pre and post 6 weeks of the passive heating intervention during the first and final heating visits at time points of pre-hot water immersion, 0 hours post and 3 hours post hot water immersion
Cerebral oxygenation
Time frame: Pre and post 6 weeks of the passive heating intervention during the first and final heating visits at time points of pre-hot water immersion, 0 hours post and 3 hours post hot water immersion
Maximum quadriceps strength
Time frame: Pre and post 6 weeks of passive heating and pre and post 6 weeks no intervention with 6 weeks washout between arms
Maximum grip strength
Time frame: Pre and post 6 weeks of passive heating and pre and post 6 weeks no intervention with 6 weeks washout between arms
Lower extremity function
Time frame: Pre and post 6 weeks of passive heating and pre and post 6 weeks no intervention with 6 weeks washout between arms
Quadriceps muscle electrical activity
Time frame: Pre and post 6 weeks of passive heating and pre and post 6 weeks no intervention with 6 weeks washout between arms
Balance capacity
Time frame: Pre and post 6 weeks of passive heating and pre and post 6 weeks no intervention with 6 weeks washout between arms
Gait characteristics
Time frame: Pre and post 6 weeks of passive heating and pre and post 6 weeks no intervention with 6 weeks washout between arms
Total minutes of physical activity (light, moderate, moderate to vigorous physical activity).
Time frame: Pre and during the final week of 6 weeks of passive heating and pre and during the final week of 6 weeks no intervention with 6 weeks washout between arms
Sleep efficiency (time in bed + time asleep)
Time frame: Pre and during the final week of 6 weeks of passive heating and pre and during the final week of 6 weeks no intervention with 6 weeks washout between arms
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 6 Aug 2025.
- Derived from this study: PubMed 42010888Piccolo DD, Corbett J, Exell TA, Moore JM, Wright A, Alnajjar MGA, Hudson LC, Marsh PA, Praskacova V, McNarry MA, Mackintosh KA, Saynor ZL, Shepherd AI. Effect of repeated hot water immersion on muscle strength, power, function and physical activity in healthy older adults: A randomised crossover trial. Exp Physiol. 2026 Apr 20:10.1113/EP093501. doi: 10.1113/EP093501. Online ahead of print.
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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.
Zoe Saynor, PhD study director
University of Portsmouth
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Passive heating in people with Aging, run by University of Portsmouth at 1 site in United Kingdom.
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 7 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 6 Aug 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 United Kingdom. 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?
Brachial artery flow-mediated dilation (time frame: Pre and post 6 weeks of passive heating and pre and post 6 weeks no intervention with 6 weeks washout between arms). 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 NCT05618197, 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 6 Aug 2025.