Physical InactivityHEAT-RPANCT07847424
Heat Therapy During Reduced Physical Activity
A study testing Sauna and Reduced Physical Activity in people with Physical Inactivity and Vascular Dysfunction, run by Brigham Young University at 1 site in United States.
Trial summary
The purpose of this randomized controlled trial is to determine whether daily Finnish dry sauna therapy attenuates the adverse cardiovascular, muscular, and metabolic effects of seven days of experimentally reduced physical activity in healthy adults. Read more about this study
- Who is it for?
- Ages 18 years and olderHealthy volunteers can take part
- Conditions the study is for
- Physical Inactivity, Vascular Dysfunction, Skeletal Muscle Atrophy
- What is being tested?
- Sauna and Reduced Physical Activity
- Type of treatment
- Medical device, Lifestyle or therapy programme
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 60 participants
- Where
- 1 siteUnited States
- Study dates
- 1 Jan 2026to May 2027
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
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 years and older
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- Adults aged 18 years or older
- Healthy men and premenopausal women
- Able and willing to provide written informed consent
- Able to perform knee-extension cycling exercise
- Stable habitual physical activity for at least 3 months before enrollment
- Pass the American College of Sports Medicine (ACSM) Preparticipation Health Screening
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- Not currently taking medications known to affect cardiovascular function (e.g., antihypertensive medications or beta-blockers)
- No regular sauna or hot-tub use (fewer than six exposures during the previous 2 months)
- Willing and able to comply with all study procedures, including temporary reduction of physical activity, daily sauna visits, physiological testing, and follow-up assessments
Who cannot join
- Younger than 18 years of age
- Failure to pass the ACSM Preparticipation Health Screening
- Unable or unwilling to perform exercise testing
- Current cigarette or marijuana use
- Pregnant or planning to become pregnant during the study
- History or current diagnosis of cardiovascular disease, metabolic disease, or cognitive impairment
Show all 11Show fewer
- Use of medications known to influence cardiovascular function or exercise tolerance (e.g., antihypertensive medications or beta-blockers)
- Regular sauna or hot-tub use (six or more exposures during the previous 2 months)
- History of heat-related illness
- Any condition that, in the opinion of the investigators, would interfere with safe participation or interpretation of study results
- Inability to understand the study procedures or provide informed consent
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
United States1 site, 1 recruiting
- Recruiting
Brigham Young University
Provo, Utah, 84602
Robert D Hyldahl, PhD, 8014221237, robhyldahl@byu.edu
Jayson R Gifford, PhD, 8014223090, jaysongifford@byu.edu
About this study
Official title: Can Heat Therapy Improve Cardiovascular Health During Periods of Reduced Physical Activity?
The purpose of this randomized controlled trial is to determine whether daily Finnish dry sauna therapy attenuates the adverse cardiovascular, muscular, and metabolic effects of seven days of experimentally reduced physical activity in healthy adults.
Participants will be randomized to one of three groups: (1) maintained habitual physical activity with daily sauna therapy, (2) reduced physical activity with daily room-temperature sauna visits (control), or (3) reduced physical activity with daily sauna therapy. Reduced physical activity will be achieved by decreasing daily step count to approximately 1,000 steps per day with the assistance of a power wheelchair.
Outcome measures include vascular endothelial function, exercise tolerance, muscle protein synthesis, body composition, blood pressure, glucose regulation, and physiological responses to heat exposure. The study will determine whether passive heat therapy can serve as a practical intervention to preserve cardiometabolic health during short periods of reduced mobility.
Read the detailed description
Reduced physical activity resulting from illness, injury, hospitalization, or other temporary limitations rapidly impairs cardiovascular, skeletal muscle, and metabolic health. Even short-term reductions in daily physical activity are associated with decreased endothelial function, reduced aerobic capacity, loss of muscle mass, and impaired insulin sensitivity.
Previous work from our laboratory has demonstrated that localized heat therapy producing exercise-like increases in muscle temperature attenuates several detrimental adaptations associated with limb immobilization. The present study investigates whether whole-body heat therapy delivered through Finnish dry sauna bathing can similarly reduce the adverse effects of whole-body reductions in physical activity.
Healthy adults will be randomly assigned to one of three intervention groups:
- Habitual physical activity with daily Finnish dry sauna therapy
- Reduced physical activity (~1,000 steps/day) with daily room-temperature sauna visits
- Reduced physical activity (~1,000 steps/day) with daily Finnish dry sauna therapy
The intervention will last seven days. Cardiovascular function, exercise tolerance, muscle protein synthesis, body composition, glucose regulation, blood pressure, and additional physiological variables will be assessed before and after the intervention. The findings will determine whether passive heat therapy is an effective strategy for preserving cardiometabolic health during temporary reductions in physical activity.
- Being tested
- Sauna, Reduced Physical Activity
- Keywords
- Heat Therapy, Physical Inactivity, Sauna, Disuse, Protein Synthesis, Vascular Health
- Medical subject headings
- Sedentary Behavior, Muscular Atrophy, Hyperthermia
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
SaunaDevice
Participants will complete one supervised dry sauna session each day for seven consecutive days. Sauna exposure will be delivered according to the study protocol using a standard Finnish dry sauna.
Reduced Physical ActivityBehavioural
Participants will reduce daily step count to approximately 1,000 steps per day for seven consecutive days. A power wheelchair will be used to assist participants in minimizing ambulation while maintaining normal daily activities.
| Study group | Role | What they receive |
|---|---|---|
| Habitual Physical Activity + Sauna | Experimental | Participants will maintain their habitual level of physical activity for seven consecutive days while undergoing one supervised Finnish dry sauna session each day. Sauna treatments will consist of standard Finnish dry sauna exposure according to the study protocol. Participants will undergo comprehensive cardiovascular, muscular, metabolic, and physiological assessments before and after the intervention. Receives: Device: Sauna |
| Reduced Physical Activity + Room-Temperature Sauna (Control) | Sham comparator | Participants will reduce daily physical activity to approximately 1,000 steps per day for seven consecutive days with assistance from a power wheelchair. Participants will attend daily room-temperature sauna sessions that replicate the timing and environment of the sauna intervention without therapeutic heat exposure. Comprehensive outcome assessments will be completed before and after the intervention. Receives: Behavioral: Reduced Physical Activity |
| Reduced Physical Activity + Dry Sauna | Experimental | Participants will reduce daily physical activity to approximately 1,000 steps per day for seven consecutive days with assistance from a power wheelchair while also completing one supervised Finnish dry sauna session each day. Outcome measures will be assessed before and after the intervention to determine whether heat therapy attenuates the adverse physiological effects of reduced physical activity. Receives: Device: Sauna; Behavioral: Reduced Physical Activity |
What is being measured
The primary outcome is the main question the study is designed to answer.
Femoral artery endothelial function
Common femoral artery blood flow will be measured using Doppler ultrasound at rest and during passive movement of the lower leg through approximately 90 degrees of motion. The hyperemic response may be expressed as peak blood flow, change from resting blood flow, and/or blood-flow area under the curve. The change from baseline to post-intervention will be compared among groups.
Measured: This outcome will be assessed four days prior to the start of the intervention (Day -4) and again 1 day following the final sauna visit (Day 8)
Change in Maximum Knee-Extension Cycling Power
Maximum exercise power will be determined during a graded knee-extension cycling test in which resistance is progressively increased until the participant can no longer maintain the required cadence. Maximum power will be reported in watts.
Measured: This outcome will be assessed four days prior to the start of the intervention (Day -4) and again 1 day following the final sauna visit (Day 8)
Change in Whole-Body Lean Mass
Whole-body lean mass will be measured using dual-energy X-ray absorptiometry. Lean mass will be reported in kilograms, and the change from baseline to post-intervention will be compared among groups.
Measured: This outcome will be assessed four days prior to the start of the intervention (Day -4) and again 1 day following the final sauna visit (Day 8)
Integrated Skeletal Muscle Protein Synthesis Rate
The integrated fractional synthesis rate of skeletal muscle protein will be determined using deuterium oxide labeling and vastus lateralis muscle biopsies. Deuterium incorporation into newly synthesized muscle protein will be quantified by mass spectrometry and expressed as the fractional synthesis rate over the study period, such as percentage per day. Rates will be compared among the three intervention groups.
Measured: Baseline (Day -4) and Day 8
Secondary outcomes (4)
Change in Leg Lean Mass
Regional leg lean mass will be measured using dual-energy X-ray absorptiometry and reported in kilograms. The change from baseline to post-intervention will be compared among groups.
Measured: This outcome will be assessed four days prior to the start of the intervention (Day -4) and again 1 day following the final sauna visit (Day 8)
Change in Mean Interstitial Glucose Concentration
Interstitial glucose concentrations will be monitored using a continuous glucose monitor. Mean glucose concentration will be calculated for the habitual-activity or baseline monitoring period and for the 7-day intervention period and reported in milligrams per deciliter.
Measured: Days -4, -3, -2, -1, 0, 1, 2, 3, 4, 5, 6, 7, 8
Mean Daily Step Count During the Intervention
Daily physical activity will be measured using an accelerometer worn on the wrist, ankle, or waist. Mean steps per day during the 7-day intervention will be used to assess adherence to the habitual-activity or reduced-activity assignment.
Measured: Days -4, -3, -2, -1, 0, 1, 2, 3, 4, 5, 6, 7, 8
Change in Core Temperature During Sauna Exposure
Core temperature will be measured using an esophageal temperature probe during the first and final sauna treatments. The change from pre-sauna temperature to peak temperature during sauna will be reported in degrees Celsius.
Measured: Day 1 and Day 8
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted29 Sep 2026
- Study start1 Jan 2026
- Primary completionJan 2027 (estimated)
- Study completionMay 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Physical InactivityStudies 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
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- Participants will be randomly assigned to one of three parallel groups for a 7-day intervention: (1) habitual physical activity with daily Finnish dry sauna therapy, (2) reduced physical activity (\~1,000 steps/day) with daily room-temperature sauna visits (control), or (3) reduced physical activity (\~1,000 steps/day) with daily Finnish dry sauna therapy. All participants will complete identical pre- and post-intervention outcome assessments.
- Masking
- Single blind
- Who is masked
- Outcomes assessor
- Enrolment
- 60 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Brigham Young University
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Rob Hyldahl, Brigham Young University
- Investigators
- Robert D Hyldahl, PhD, Principal investigator, Brigham Young University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07847424
- Sponsor's protocol ID
- HT-RPA-001
- Acronym
- HEAT-RPA
- Status last verified
- Sep 2026
- First submitted
- 14 Jul 2026
- Last updated
- 29 Sep 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: Individual participant data will not be shared because participant consent did not include public data sharing, and protection of participant confidentiality is a priority.
Study at a glance
From the registry record, last updated by the sponsor on 29 Sep 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Can Heat Therapy Improve Cardiovascular Health During Periods of Reduced Physical Activity?
- ClinicalTrials.gov ID
- NCT07847424
- Acronym / sponsor ID
- HEAT-RPA / HT-RPA-001
- Keywords
- Heat Therapy, Physical Inactivity, Sauna, Disuse, Protein Synthesis, Vascular Health
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 60 participants (estimated)
- Lead sponsor
- Brigham Young UniversityUniversity, hospital or other
- Study start
- 1 Jan 2026 (actual)
- Primary completion
- Jan 2027 (estimated)
- Study completion
- May 2027 (estimated)
- First posted
- 29 Sep 2026 (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.
The purpose of this randomized controlled trial is to determine whether daily Finnish dry sauna therapy attenuates the adverse cardiovascular, muscular, and metabolic effects of seven days of experimentally reduced physical activity in healthy adults.
Participants will be randomized to one of three groups: (1) maintained habitual physical activity with daily sauna therapy, (2) reduced physical activity with daily room-temperature sauna visits (control), or (3) reduced physical activity with daily sauna therapy. Reduced physical activity will be achieved by decreasing daily step count to approximately 1,000 steps per day with the assistance of a power wheelchair.
Outcome measures include vascular endothelial function, exercise tolerance, muscle protein synthesis, body composition, blood pressure, glucose regulation, and physiological responses to heat exposure. The study will determine whether passive heat therapy can serve as a practical intervention to preserve cardiometabolic health during short periods of reduced mobility.
Detailed description
Reduced physical activity resulting from illness, injury, hospitalization, or other temporary limitations rapidly impairs cardiovascular, skeletal muscle, and metabolic health. Even short-term reductions in daily physical activity are associated with decreased endothelial function, reduced aerobic capacity, loss of muscle mass, and impaired insulin sensitivity.
Previous work from our laboratory has demonstrated that localized heat therapy producing exercise-like increases in muscle temperature attenuates several detrimental adaptations associated with limb immobilization. The present study investigates whether whole-body heat therapy delivered through Finnish dry sauna bathing can similarly reduce the adverse effects of whole-body reductions in physical activity.
Healthy adults will be randomly assigned to one of three intervention groups:
- Habitual physical activity with daily Finnish dry sauna therapy
- Reduced physical activity (~1,000 steps/day) with daily room-temperature sauna visits
- Reduced physical activity (~1,000 steps/day) with daily Finnish dry sauna therapy
The intervention will last seven days. Cardiovascular function, exercise tolerance, muscle protein synthesis, body composition, glucose regulation, blood pressure, and additional physiological variables will be assessed before and after the intervention. The findings will determine whether passive heat therapy is an effective strategy for preserving cardiometabolic health during temporary reductions in physical activity.
Study design
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind (outcomes assessor)
- Number of arms
- 3
- Model description
- Participants will be randomly assigned to one of three parallel groups for a 7-day intervention: (1) habitual physical activity with daily Finnish dry sauna therapy, (2) reduced physical activity (~1,000 steps/day) with daily room-temperature sauna visits (control), or (3) reduced physical activity (~1,000 steps/day) with daily Finnish dry sauna therapy. All participants will complete identical pre- and post-intervention outcome assessments.
| Arm | Type | Receives |
|---|---|---|
| Habitual Physical Activity + Sauna | Experimental | Device: SaunaParticipants will maintain their habitual level of physical activity for seven consecutive days while undergoing one supervised Finnish dry sauna session each day. Sauna treatments will consist of standard Finnish dry sauna exposure according to the study protocol. Participants will undergo comprehensive cardiovascular, muscular, metabolic, and physiological assessments before and after the intervention. |
| Reduced Physical Activity + Room-Temperature Sauna (Control) | Sham comparator | Behavioral: Reduced Physical ActivityParticipants will reduce daily physical activity to approximately 1,000 steps per day for seven consecutive days with assistance from a power wheelchair. Participants will attend daily room-temperature sauna sessions that replicate the timing and environment of the sauna intervention without therapeutic heat exposure. Comprehensive outcome assessments will be completed before and after the intervention. |
| Reduced Physical Activity + Dry Sauna | Experimental | Device: Sauna, Behavioral: Reduced Physical ActivityParticipants will reduce daily physical activity to approximately 1,000 steps per day for seven consecutive days with assistance from a power wheelchair while also completing one supervised Finnish dry sauna session each day. Outcome measures will be assessed before and after the intervention to determine whether heat therapy attenuates the adverse physiological effects of reduced physical activity. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (9 listed)
- Adults aged 18 years or older
- Healthy men and premenopausal women
- Able and willing to provide written informed consent
- Able to perform knee-extension cycling exercise
- Stable habitual physical activity for at least 3 months before enrollment
Key exclusion criteria (11 listed)
- Younger than 18 years of age
- Failure to pass the ACSM Preparticipation Health Screening
- Unable or unwilling to perform exercise testing
- Current cigarette or marijuana use
- Pregnant or planning to become pregnant during the study
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 |
|---|---|---|
| SaunaParticipants will complete one supervised dry sauna session each day for seven consecutive days. Sauna exposure will be delivered according to the study protocol using a standard Finnish dry sauna. | Device | Habitual Physical Activity + Sauna, Reduced Physical Activity + Dry Sauna |
| Reduced Physical ActivityParticipants will reduce daily step count to approximately 1,000 steps per day for seven consecutive days. A power wheelchair will be used to assist participants in minimizing ambulation while maintaining normal daily activities. | Behavioural | Reduced Physical Activity + Dry Sauna, Reduced Physical Activity + Room-Temperature Sauna (Control) |
Primary outcome
Femoral artery endothelial function
Time frame: This outcome will be assessed four days prior to the start of the intervention (Day -4) and again 1 day following the final sauna visit (Day 8)
Common femoral artery blood flow will be measured using Doppler ultrasound at rest and during passive movement of the lower leg through approximately 90 degrees of motion. The hyperemic response may be expressed as peak blood flow, change from resting blood flow, and/or blood-flow area under the curve. The change from baseline to post-intervention will be compared among groups.
Change in Maximum Knee-Extension Cycling Power
Time frame: This outcome will be assessed four days prior to the start of the intervention (Day -4) and again 1 day following the final sauna visit (Day 8)
Maximum exercise power will be determined during a graded knee-extension cycling test in which resistance is progressively increased until the participant can no longer maintain the required cadence. Maximum power will be reported in watts.
Change in Whole-Body Lean Mass
Time frame: This outcome will be assessed four days prior to the start of the intervention (Day -4) and again 1 day following the final sauna visit (Day 8)
Whole-body lean mass will be measured using dual-energy X-ray absorptiometry. Lean mass will be reported in kilograms, and the change from baseline to post-intervention will be compared among groups.
Integrated Skeletal Muscle Protein Synthesis Rate
Time frame: Baseline (Day -4) and Day 8
The integrated fractional synthesis rate of skeletal muscle protein will be determined using deuterium oxide labeling and vastus lateralis muscle biopsies. Deuterium incorporation into newly synthesized muscle protein will be quantified by mass spectrometry and expressed as the fractional synthesis rate over the study period, such as percentage per day. Rates will be compared among the three intervention groups.
4 secondary outcomes
Change in Leg Lean Mass
Time frame: This outcome will be assessed four days prior to the start of the intervention (Day -4) and again 1 day following the final sauna visit (Day 8)
Change in Mean Interstitial Glucose Concentration
Time frame: Days -4, -3, -2, -1, 0, 1, 2, 3, 4, 5, 6, 7, 8
Mean Daily Step Count During the Intervention
Time frame: Days -4, -3, -2, -1, 0, 1, 2, 3, 4, 5, 6, 7, 8
Change in Core Temperature During Sauna Exposure
Time frame: Day 1 and Day 8
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 29 Sep 2026.
- Individual participant dataSharing planned: No. Individual participant data will not be shared because participant consent did not include public data sharing, and protection of participant confidentiality is a priority.
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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.
Robert D Hyldahl, PhD principal investigator
Brigham Young University
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Sauna and Reduced Physical Activity in people with Physical Inactivity and Vascular Dysfunction, run by Brigham Young University at 1 site in United States.
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 9 inclusion and 11 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: looking for participants now, as of the sponsor's last update on 29 Sep 2026. 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 States. 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. Some participants in this study may receive a placebo. 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?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Robert D Hyldahl, PhD (8014221237, robhyldahl@byu.edu), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Femoral artery endothelial function (time frame: This outcome will be assessed four days prior to the start of the intervention (Day -4) and again 1 day following the final sauna visit (Day 8)). The study lists 4 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 29 Sep 2026.