ClinicalTrials.gg
CompletedNCT05706181Updated Jun 5, 2026

Heat Therapy, Functional Capacity, and Vascular Health in Older Adults

A Phase 1/2 interventional study of Home-based leg heat therapy and Home-based sham therapy in Aging Well, Walking, Difficulty and Hyperemia, sponsored by University of North Texas Health Science Center. Completed at 1 site in United States. Open to participants aged 55 Years to 80 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-06-05.

Sponsored by University of North Texas Health Science Center · Phase 1/2, Interventional, and Basic science

Phase
Phase 1/2
Study type
Interventional
Enrollment
21
Allocation
Randomized
Ages
55 Years to 80 Years
Sex
All
01

Study summary

To test the hypothesis that home-based leg heat therapy improves functional capacity, vascular function, and exercise hyperemia in older adults.

Read the detailed description

Chronic whole-body heating (i.e., heat therapy) has gained attention as a novel strategy to improve clinical and physiological outcomes in a number of populations. However, whole-body heat therapy is quite uncomfortable and may require trained personnel to ensure participant safety, especially for those more at risk for heat-related illness. Moreover, the applicability and acceptability of whole-body heat therapy are questionable as equipment cost is substantial and adherence will be low if individuals are required to travel if they cannot afford in-home therapy. Home-based leg heat therapy offers an opportunity to leverage the demonstrated benefits of whole-body heat therapy while managing safety and convenience.

The hypothesis will be addressed in the following Specific Aims:

Aim 1: Determine the extent to which home-based leg heat therapy improves functional capacity in older adults. Functional capacity will be assessed before and after heat therapy or sham intervention via the 6-min walk test and the Short Physical Performance Battery.

Aim 2: Determine if home-based leg heat therapy improves vascular function and exercise hyperemia in the older adults of Aim 1. Using state-of-the-art techniques of skeletal muscle microdialysis and high-resolution duplex ultrasound, the investigators will pharmacodissect mechanisms of vascular function and exercise hyperemia before and after each intervention. The outcomes of Aim 2, while providing insight into the mechanisms whereby heat therapy improves functional capacity, should be considered independent of the outcomes of Aim 1 given that vascular health is a key independent, yet modifiable risk factor for cardiovascular morbidity and mortality.

02

Conditions studied

  • Aging Well
  • Walking, Difficulty
  • Hyperemia

Keywords

  • Healthy aging
  • Functional capacity
  • Exercise hyperemia
  • Vascular function
  • heat therapy
03

In context

Mobility Limitation

381 studies on the registry are indexed under Mobility Limitation; 108 are open to participants now.

This study's enrollment of 21 is below the median of 46 across 316 interventional studies indexed under Mobility Limitation.

Browse Mobility Limitation studies →

Lead sponsor

University of North Texas Health Science Center is the lead sponsor of 31 studies on the registry; 3 are open to participants now.

Counted across the registry records on this site, refreshed daily.

04

Who can participate

Ages eligible
55 Years to 80 Years
Sexes eligible
All
Accepts healthy volunteers
Yes

Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.

Inclusion criteria

  1. 55 to 80 years of age
  2. No tobacco/nicotine use within preceding 6 months (e.g., cigarettes, chewing tobacco, nicotine gum or patches, and vapor smoking)
  3. Systolic blood pressure \<140 mmHg; diastolic blood pressure \<90 mmHg
  4. Normal 12-lead (reviewed by a physician)
  5. Normal clinical results from a medical exam reviewed by a board-certified physician (e.g., General Health Questionnaire - see attached document)
  6. (BMI) \<40 unless athletic/muscular build; calculation = body weight (kg)/height (m2)
  7. Females Only:

Exclusion criteria

Exclusion Criteria:

  1. Not meeting the age criteria
  2. (BMI) >40 unless athletic/muscular build; calculation = body weight (kg)/height (m2)
  3. Use of tobacco or nicotine products within the last 6 months (tobacco cigarettes, chewing tobacco, nicotine patches or gum)
  4. Not abstaining from the following 24 hours prior to the experimental session: exercise, alcoholic substances, prescription or non-prescription medications (unless cleared by the medical screener), dietary supplements, herbal medications, caffeinated substances (including chocolate, coffee, tea (iced or hot), caffeinated energy drinks, and sodas)
  5. S who weigh less than 80 lbs
  6. Use of prescription drugs, non-prescription drugs or herbal medicines known to alter vascular function unless cleared prior to the study
  7. Use of anti-hypertensive medications
  8. Use of beta blockers
  9. Daily use of bronchodilators
  10. Current use of anti-coagulant therapy
  11. Current use of hormone replacement therapy (e.g., estrogen, testosterone)
  12. Current diagnosis of cancer
  13. Signs of overt cardio-metabolic abnormalities (e.g., uncontrolled diabetes - >7.5, a resting systolic blood pressure >140mmHg or diastolic blood pressure >90mmHg; abnormal 12-lead )
  14. History of cerebrovascular abnormalities (e.g., prior stroke, , epilepsy, increased intracranial pressure)
  15. Known history of atherosclerosis (i.e., plaque formation)
  16. Autonomic dysfunction (e.g., Shy-Drager Syndrome, Bradbury-Eggleston syndrome, idiopathic orthostatic hypotension)
  17. Respiratory illnesses (e.g., chronic asthma (including exercise-induced asthma), , Reactive Airway Disease). Note: subjects with exercised-induced asthma or who have had COVID-19 will be allowed to participate
  18. History of anaphylaxis
  19. Severe phobia of needles
  20. History of alcohol or drug abuse which inhibits the participants ability to complete this study
  21. Latex allergy
  22. Known allergies or sensitivities to drugs used in the study (e.g., Lidocaine HCL, acetylcholine HCL, methacholine chloride, sodium nitroprusside, nitroglycerin, or related drugs)
  23. Implanted electronic medical devices (e.g. cardiac pacemaker)
  24. Tissue or skin abnormalities of the legs (e.g., infection, injury, open wound, ischemic tissue, phlebitis, active bleeding, neuropathy)
  25. Tissue or skin abnormalities of the arm (e.g., unhealed or open wound or circulatory deficits)
  26. Current Fever (oral temp >99.5 °F/ 37.5 °C) aa) Current use of PDE3 inhibitors (e.g., Viagra) or soluble guanylate cyclase (sGC) stimulators (e.g., riociguat), or unwillingness to withhold medication for 2 weeks prior to laboratory testing bb) Diagnosis of neurological disease or cognitive dysfunction cc) Cardiac surgery or cardiac events (e.g., coronary artery bypass graft surgery, myocardial infarction, heart failure) dd) Abnormal clotting, clots in deep veins in the legs or pelvis, or blood clots to the lungs ee) Individuals who have had mastectomies ff) History of methemoglobinemia
Terms in these criteria, in plain language(6)

Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.

ECG (electrocardiogram)

A recording of the heart’s electrical activity, taken with stickers on the chest, arms and legs. It takes a few minutes and does not hurt.

BMI (body mass index)

Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.

What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.

Postmenopausal

Periods have stopped for good: usually no period for 12 months in a row without another medical reason, sometimes confirmed by a blood test (FSH).

HbA1c

A blood test of average blood sugar over the past two to three months, given as a percentage or in mmol/mol. 6.5% (48 mmol/mol) or more is the usual threshold for diabetes, normally confirmed by a second test.

TIA (transient ischaemic attack)

A “mini-stroke”: temporary stroke-like symptoms caused by reduced blood flow to part of the brain, spinal cord or eye, without signs of a new stroke on a scan.

Stroke symptoms need emergency care at once, even if they go away.

COPD

Chronic obstructive pulmonary disease: long-term lung disease that makes it hard to breathe out, including emphysema and chronic bronchitis.

05

Study design

Phase
Phase 1 / Phase 2
Primary purpose
Basic science
Allocation
Randomized
Intervention model
Parallel assignment
Masking
Triple (Participant, Investigator, Outcomes assessor)
Enrollment
21 participants (actual)

Study arms

  • Experimental
    Home-based heat therapy and functional capacity in older adults

    The investigators will determine the extent to which home-based leg heat therapy improves functional capacity in older adults. Functional capacity will be assessed before and after heat therapy or sham intervention via the 6-min walk test and the Short Physical Performance Battery.

    Other: Home-based leg heat therapy · Other: Home-based sham therapy

  • Experimental
    Home-based heat therapy and vascular function and exercise hyperemia in older adults

    The investigators will determine if home-based leg heat therapy improves vascular function and exercise hyperemia in the older adults of Aim 1. Using state-of-the-art techniques of skeletal muscle microdialysis and high-resolution duplex ultrasound, the investigators will pharmacodissect mechanisms of vascular function and exercise hyperemia before and after each intervention. The outcomes of Aim 2, while providing insight into the mechanisms whereby heat therapy improves functional capacity, should be considered independent of the outcomes of Aim 1 given that vascular health is a key independent, yet modifiable risk factor for cardiovascular morbidity and mortality.

    Other: Home-based leg heat therapy · Other: Home-based sham therapy

Interventions

  • OtherHome-based leg heat therapy

    Participants will be required to perform 8 weeks of leg heat therapy using water-perfused pants 4 times per week, with each session lasting 60 min. Skin temperature will be heated to about 40 °C. The pants heating system (consisting of pants and a water circulator/heater) can finely and uniformly control these designated skin temperatures. Participants will be randomly assigned to a group and provided with the pant heating system as well as a log book in which they are required to track the dates of each session. Participants will also measure their blood pressure and heart rate prior to, during, and immediately after each heating session using a portable oscillometric device provided by our laboratory.

  • OtherHome-based sham therapy

    Participants will be required to perform 8 weeks of leg heat therapy using water-perfused pants 4 times per week, with each session lasting 60 min. Skin temperature will be heated to about 40 °C. The pants heating system (consisting of pants and a water circulator/heater) can finely and uniformly control these designated skin temperatures. Participants will be randomly assigned to a group and provided with the pant heating system as well as a log book in which they are required to track the dates of each session. Participants will also measure their blood pressure and heart rate prior to, during, and immediately after each heating session using a portable oscillometric device provided by our laboratory.

06

What researchers measure

Primary outcomes

  1. 6 minute walk test

    The distance, in meters, covered while walking for 6 minutes will be used to assess functional capacity.

    Time frame: Before sham or heat therapy

  2. 6 minute walk test

    The distance, in meters, covered while walking for 6 minutes will be used to assess functional capacity.

    Time frame: After 8 weeks of heat therapy or sham

  3. Macrovascular function

    High-resolution duplex ultrasound will be used to assess vasodilation following a 5 minutes of leg ischemia. Vasodilation will calculated as the percent change in diameter of the superficial femoral that occurs following ischemia.

    Time frame: Before sham or heat therapy

  4. Macrovascular function

    High-resolution duplex ultrasound will be used to assess vasodilation following a 5 minutes of leg ischemia. Vasodilation will calculated as the percent change in diameter of the superficial femoral that occurs following ischemia.

    Time frame: After 8 weeks of heat therapy or sham

  5. Microvascular function

    The microdialysis technique will be used to delivery small amounts of acetylcholine or methacholine and sodium nitroprusside to the skeletal muscle of the thigh. Endothelial-dependent and endothelial-independent microvascular function can then be examined by assessing the increase in skeletal muscles blood flow during the infusion of acetylcholine/methacholine and sodium nitroprusside, respectively.

    Time frame: Before sham or heat therapy

  6. Microvascular function

    The microdialysis technique will be used to delivery small amounts of acetylcholine or methacholine and sodium nitroprusside to the skeletal muscle of the thigh. Endothelial-dependent and endothelial-independent microvascular function can then be examined by assessing the increase in skeletal muscles blood flow during the infusion of acetylcholine/methacholine and sodium nitroprusside, respectively.

    Time frame: After 8 weeks of heat therapy or sham

  7. Blood flow response to exercise

    High-resolution duplex ultrasound will be used to assess the change in blood flow during graded plantar flexion exercise.

    Time frame: Before sham or heat therapy

  8. Blood flow response to exercise

    High-resolution duplex ultrasound will be used to assess the change in blood flow during graded plantar flexion exercise.

    Time frame: After 8 weeks of heat therapy or sham

Secondary outcomes

  1. Physical performance Battery

    Likert scale-based scores will be tabulated from a side-by-side stand test, semi-tandem stand test, and a tandem stand test.

    Time frame: Before sham or heat therapy

  2. Physical performance Battery

    Likert scale-based scores will be tabulated from a side-by-side stand test, semi-tandem stand test, and a tandem stand test.

    Time frame: After 8 weeks of heat therapy or sham

07

Study locations

1 site
  • University of North Texas Health Science Center
    Fort Worth, Texas 76107, United States
08

References and documents

Individual participant data

Plan to share: No

09

Timeline

Tracking since Sep 25, 2026
ElapsedEstimatedEstimated, not yet reached

Ran from Nov 2022 to primary completion in Jun 2025, 31 months.

How these figures are worked out, and which studies are left out of them.

Registered
Dec 21, 2022
First posted
Jan 31, 2023
StartActual
Nov 3, 2022
Primary completionActual
Jun 30, 2025
CompletionActual
Jul 30, 2025
Last update
Jun 5, 2026
What these dates mean
Start.
When the first participant enrolled; while estimated, when the study expects to open to recruitment.
Primary completion.
When the last participant was examined or treated to collect data for the study's main question, its primary outcome. A study that stopped early gives the date its data collection stopped.
Completion.
When the last participant's last visit took place, for every outcome, secondary ones and side effects included: the end of the study. Often later than primary completion, sometimes the same day.
Actual and Est.
Actual means the registry says the date has happened. Est. (estimated) is a date the sponsor plans or expects. It can still move, and the sponsor is expected to change it to actual once it has passed.
No changes since tracking began. The registry record was last updated on Jun 5, 2026, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗
10

Registry details

Key details

Study ID
NCT05706181
Lead sponsor
University of North Texas Health Science Center
Collaborators
American Heart Association
Responsible party
Sponsor
First posted
Jan 31, 2023
Start date
Nov 3, 2022
Primary completion
Jun 30, 2025
Completion
Jul 30, 2025
Last update
Jun 5, 2026

Oversight

Data monitoring committee
No
FDA-regulated drug
No
FDA-regulated device
No
View the source record on ClinicalTrials.gov ↗

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