Individuals without history of cardiovascular disease and at least 18 years of age will take a baseline (at rest) cardiopulmonary exercise test (CPX) and have a cardiac echocardiogram to measure myocardial deformation. CPX and echocardiograms will be repeated during exercise sessions at 3 visits over a 12 week period.

Individuals at risk of heart failure and a preserved ejection fraction of at least 50% will take a baseline (at rest) cardiopulmonary exercise test (CPX) and have a baseline cardiac echocardiogram to measure myocardial deformation. CPX and echocardiograms will be repeated during exercise sessions at 6 visits over a 12 week period. A cardiac rehabilitation exercise program will also occur over 12 weeks.

Aerobic cardiac exercise training will be provided over the 12 week study duration.

Myocardial deformation imaging (e.g. strain, strain rate, torsion) requires clear 2-dimensional echocardiography images that will be obtain at rest and during mild and moderate intensity exercise. Images will be captured during 6-10 minute bouts of exercise on a tilting exercise table. Comparisons will be made on resting and exercise values between groups. Our hypothesis is that strain rate will not increase in patients at risk of heart failure demonstrating lack of cardiovascular reserve.

Stroke volume is the volume of blood (in milliliters) ejected during each heart contraction, It is measured by combined Doppler and 2-dimensional echocardiography. A surrogate measure of stroke volume (oxygen-pulse) can also be obtained during cardiopulmonary exercise testing by dividing the measured oxygen consumption by the heart rate. Our hypothesis is that stroke volume will plateau early after exercise onset in patients at risk of heart failure and this plateau will correlate with a reduction in strain rate.