Passive Heat Therapy for People With COPD

Not Applicable

Recruiting

• Conditions: COPD; Cardiovascular Diseases
• Interventions: Behavioral: Sham Immersion; Behavioral: Passive Heat Therapy

• Registration Number: NCT05962164
• Lead Sponsor: University of British Columbia

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.

Study Timeline

• Study First Submitted: 2023-06-30
• Study First Submitted QC: 2023-07-18
• Study First Posted: 2023-07-27
• Study Start: 2023-08-17
• Status Verified: 2025-04
• Last Update Submitted: 2025-04-02
• Last Update Posted: 2025-04-04
• Primary Completion: 2026-05-31
• Study Completion: 2026-05-31

Recruitment & Eligibility

• Status: RECRUITING
• Sex: All
• Target Recruitment: 32

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.

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
Sham Immersion	Sham Immersion	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.
Passive Heat Therapy	Passive Heat Therapy	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.

Primary Outcome Measures

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

Secondary Outcome Measures

Name	Time	Method
Flow mediated dilation of the superficial femoral artery following chronic passive heat therapy.	6 weeks	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.
The acute changes in superficial femoral artery shear stress from a single bout of passive heat therapy	During procedure: 60-minutes	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.
Exercise tolerance following chronic passive heat therapy	6 weeks	The change in constant load exercise time (seconds) at 75% of peak power from baseline to post intervention.
Arterial stiffness following chronic passive heat therapy	6 weeks	The change in pulse wave velocity (m/s) measured by applanation tonometry from baseline to post intervention.
The acute changes in leg blood flow from a single bout of passive heat therapy	During procedure: 60-minutes	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.

Trial Locations

Locations (1)

University of British Columbia; 🇨🇦 Kelowna, British Columbia, Canada