The goal of this experimental study is to compare the effects of early (2nd week) cardiac rehabilitation applied in addition to usual care on functional capacity, quality of life, frailty and body composition in patients undergoing coronary artery bypass graft surgery. The main questions it aims to answer are: * Does early cardiac rehabilitation contribute to increasing functional capacity? * Does early cardiac rehabilitation have positive effects on quality of life, frailty and body composition? Participants will be divided into 2 groups (n = 50) in a randomized controlled manner. Patients in the training group (n:25) will participate in an 8-week supervised cardiac rehabilitation program as an outpatient after discharge. Patients in the control group (n:25) will be provided with usual care after discharge. The control group will be informed about secondary prevention approaches and a home-based exercise program will be recommended. In addition to secondary prevention approaches and home-based exercise program, the training group will receive 3 sessions/week, 60 minutes of supervised cardiac rehabilitation for 8 weeks. All patients will be evaluated at baseline and after 8 weeks. Researchers will compare training and control groups to see if effects on functional capacity, quality of life, frailty, body composition