Passive Heat Therapy for People With COPD

Study Overview
=================
Brief Summary
-----------------
People with Chronic Obstructive Pulmonary Disease (COPD) often develop high blood pressure and heart disease due to their sedentary lifestyle and difficulty exercising. The investigators will test if heating can mimic the health benefits of exercise by monitoring the increase in leg blood-flow using ultrasound during a 45-minute hot-water footbath. The patients will then undergo 6-weeks of hot-water footbaths to examine whether the changes to blood-flow lead to improvements in blood pressure and other indicators of heart disease risk.

Detailed Description
-----------------
People with COPD are at higher risk of developing cardiovascular disease (CVD). While exercise training is a potent therapy for CVD, people with COPD have a low tolerance for exercise due to dyspnea and premature muscle fatigue. Thus, there is a need to develop more effective strategies to improve CVD risk in people with COPD. A novel way to reduce blood pressure and enhance arterial health is with passive heat therapy (PHT). An acute 45-min bout of lower limb hot-water immersion has been shown to increase leg blood flow and reduce blood pressure in healthy older adults, suggesting that PHT could have similar hypotensive and anti-atherosclerotic effects as exercise. Augmenting leg blood flow with PHT may also have functional benefits by reducing peripheral muscle fatigue and improving exercise tolerance. No study to date has looked at the acute and chronic hemodynamic and vascular responses to PHT in people with COPD, nor whether it can acutely or chronically improve exercise tolerance.

Official Title
-----------------
The Acute and Chronic Benefits of Passive Heat Therapy for People With COPD

Conditions
-----------------
COPD, Cardiovascular Diseases

Intervention / Treatment
-----------------
* Behavioral: Passive Heat Therapy
* Behavioral: Sham Immersion


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Non-smoking individuals >40 years of age Stable (exacerbation free for >6 weeks), moderate-to-severe COPD (post bronchodilator FEV1/FVC <lower limit of normal and FEV1 z-score <2.51) Exclusion Criteria: Performing structured exercise training (i.e. pulmonary rehabilitation) Have advanced cardiac or cerebrovascular disease (i.e. a history of heart failure, previous stroke or myocardial infarction) Have uncontrolled hypertension (>160/95 mmHg at rest) Have hypotension (<110/60 mmHg) Are taking Beta Blockers Regularly (>1/week) have hot baths (>30 min) or use a hot tub or sauna. Exclusion Criteria for exercise outcomes: Have resting blood pressure > 150/95 mmHg On supplemental oxygen for hypoxemia. Musculoskeletal pain that limits their ability to perform stationary cycling.

Ages Eligible for Study
-----------------
Minimum Age: 40 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: Parallel 2-Arm Randomized Control Trial
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Passive Heat Therapy<br>Patients with COPD assigned to passive heat therapy will have their lower legs immersed in a circulating hot water ( 42°C) footbath for 45 min per session. | Behavioral: Passive Heat Therapy<br>* The intervention will consist of 6 weeks of repeated (3x/week) 45-min lower-leg immersions.<br>* Other names: Footbath;|
| Sham Comparator: Sham Immersion<br>Patients with COPD assigned to the sham condition will have their lower legs immersed in a circulating thermoneutral ( 36°C) footbath for 45 min per session. | Behavioral: Sham Immersion<br>* The sham intervention will consist of 6 weeks of repeated (3x/week) 45-min lower-leg immersions.<br>|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Mean 24-hour ambulatory blood pressure following chronic passive heat therapy | The change in 24-hour ambulatory systolic, diastolic and mean arterial blood pressure from baseline to post intervention. | 6 weeks | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Flow mediated dilation of the superficial femoral artery following chronic passive heat therapy. | The change in the percent dilation of the superficial femoral artery (measured using ultrasound) in response to reactive hyperemia (from a 5-min supra-systolic occlusion) from baseline to post intervention. | 6 weeks | 
| Arterial stiffness following chronic passive heat therapy | The change in pulse wave velocity (m/s) measured by applanation tonometry from baseline to post intervention. | 6 weeks | 
| Exercise tolerance following chronic passive heat therapy | The change in constant load exercise time (seconds) at 75% of peak power from baseline to post intervention. | 6 weeks | 
| The acute changes in leg blood flow from a single bout of passive heat therapy | Superficial femoral artery blood flow (mL/min) will be measured by duplex ultrasound. Measurements will be taken every 15-min throughout immersion until 15-min following the first session of passive heat therapy or Sham treatment. | During procedure: 60-minutes | 
| The acute changes in superficial femoral artery shear stress from a single bout of passive heat therapy | Superficial femoral artery shear stress (1/s) patterns will be measured by duplex ultrasound. Measurements will be taken every 15-min throughout immersion until 15-min following the first session of passive heat therapy or Sham treatment. | During procedure: 60-minutes | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
Passive Heat Therapy, Pulmonary Rehabilitation, Cardiovascular Health