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.

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.

Blinding of the participant to the condition (heat therapy or sham) is not possible. Data that needs to be analyzed (i.e. ultrasound videos for blood flow and FMD) will be coded by a team member that is not involved in data collection or analysis. The outcomes assessor will be blind to the participant, condition and time point of the file. Breaking of the code will only occur when all data analysis is complete.