Exercise Capacity According to Coronary Microvascular Dysfunction and Body Composition

This study is looking at how small blood vessel problems in the heart (called coronary microvascular dysfunction) affect a person's ability to exercise, and whether body composition (like the amount of muscle versus fat) plays a role. Participants undergo exercise testing and heart imaging to better understand these connections. **You may be eligible if...** - You are between 20 and 80 years old - You experience chest pain, atypical chest discomfort, or shortness of breath - Your coronary angiogram or CT scan did not show significant blockages - Your heart's pumping function is normal (50% or above) **You may NOT be eligible if...** - You have significant heart valve disease or a congenital heart defect - You have severe kidney disease or are on dialysis - You have asthma, COPD, or pulmonary hypertension - You have atrial fibrillation - You are unable to perform exercise testing (treadmill or bicycle) - You are currently taking cancer treatments Talk to your doctor to see if this trial is right for you.