Characterization of Myocardial Blood Flow During Heat Exposure

Inclusion Criteria for Healthy Participants: * Age between 18-40 years or 60-80 years * Non-smoker (≥1 year) * Non-diabetic * Normal kidney function * Body Mass Index \<30 kg/m2 * Resting blood pressure \<140/\<90 mmHg * Resting heart rate \<100 bpm Inclusion Criteria for Participants with Coronary Artery Disease: * Age between 60-80 years old * History of angiographic coronary disease (≥70% arterial diameter narrowing of at least one major epicardial coronary artery) and/or prior coronary revascularization and/or documented prior acute coronary syndrome and/or perfusion defect during stress testing * Stable medications (≥4 weeks) prior to enrollment Exclusion Criteria for Healthy Participants: * Diagnosis of heart, vascular, respiratory, neurological or metabolic disease and/or a prescription of medication for the treatment of these diseases * Pregnancy or lactation * Dyslipidemia not controlled by medication Exclusion Criteria for Participants with Coronary Artery Disease: * Recent hospitalization (\<3 months) related to coronary artery disease * Unstable angina (\<3 months) * Recent coronary artery bypass surgery (\<3 months) * Left branch block * Ejection fraction \<40% and/or clinical signs of heart failure * Severe valvular heart disease * Hypertension not controlled by medication * Diabetes not controlled by medication and/or serious complications related to diabetes