Improving Cardiac Rehabilitation Exercise Using Target Heart Rate Trial

The goal of this clinical trial is to compare two types of exercise prescriptions in cardiac rehabilitation eligible older adults (60 years or older) with heart disease. The investigators found in a single site pilot trial (insert NCTxxx) that one exercise prescription was better and are now repeating this study in a larger population at two sites (Baystate Medical Center, Springfield MA and Henry Ford Health System, Detroit MI). The main questions the investigators aim to answer are: 1. Compare two different exercise prescriptions in cardiac rehabilitation on exercise outcomes 1. Graded exercise test +Target heart rate range prescription \[GXT-THRR\] 2. Rating of perceived exertion (RPE) 2. What is the role of psychological feedback on fitness outcomes during cardiac rehabilitation and physical activity outside of cardiac rehabilitation. 3. What are the long-term clinical outcomes between the two exercise prescriptions Participants will be asked to: * Complete surveys about physical activity, exercise anxiety, exercise efficacy, and fears about exercising * Perform fitness measures (6-minute walk test, balance tests, stand to sit tests, a 400 meter walk, and handgrip strength) * Attend at least 18 sessions of cardiac rehabilitation after they are randomized to their exercise prescription group * Wear a heart rate monitor and a physical activity monitor per study protocol Participants will be randomized (flip of a coin) to either receive a graded exercise test and psychoeducational feedback or lifestyle education (nutrition for cardiac). The graded exercise test will be used to create a personalized exercise prescription with the target heart rate range calculated from the test and the lifestyle education group will use their ratings of perceived exertion for their exercise prescription.