Passive Heat Therapy for People With COPD

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.

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.