This study is for people aged 65 and older. It's about seeing if listening to *personalized music playlists* while exercising can help older adults enjoy exercise more and stick to it. The study runs for **8 months** and involves a **6-month exercise program**. Participants will exercise both with and without music playlists. The program includes **strength training** (lifting weights) and **aerobic training** (like walking or cycling) that starts with supervised classes and then moves to exercising independently at home. **Key Points:** - **Time Commitment:** Participants will engage in supervised exercise classes 2 days a week for 3 months, then 1 day a week for 3 more months, with additional follow-ups. - **Tools:** Participants will use a hip-worn activity tracker to measure activity levels, and send text messages to report feelings about exercise. - **Assessments:** Before and after the 6-month program, participants will have lab visits to check fitness, health, and quality of life. Participants need to be healthy enough to exercise, have transportation, and a safe place at home to exercise. They should not have severe health issues or be in other exercise studies.