This randomized controlled trial study aims to examine the effects of a multidimensional exercise program in cardiac surgery patients. The following hypotheses were tested: patients who received the exercise program will report significant improvement in frailty after the 12-week multidimensional exercise program. Subjects are randomly assigned to the intervention or control group. Patients in the intervention group will receive a 12-week multidimensional exercise program. Data are collected by using medical records and structural questionnaires, measuring handgrip strength, and a four-meter walk test at baseline, 6 weeks, and 12 weeks.

This study aims to develop a multidimensional exercise program and examine the effects of an exercise program on cardiac surgery patients. An experimental design is used. Subjects are recruited using convenience sampling and randomly assigned to the intervention or control group using the block randomization method. Patients in the intervention group will receive a 12-week multidimensional exercise program, including individual nursing consultation, an exercise program that includes moderate intensity walking for 30-45 minutes per day, three days per week combined resistance exercise, nutrition assessment, and instructions, and support. Data are collected by using medical records and structural questionnaires, measuring handgrip strength, and a four-meter walk test at baseline, 6 weeks, and 12 weeks. The data were analyzed using SPSS version 22.0, and data analysis methods include descriptive statistics, independent t-test, chi-square, and generalized estimating equation.

Inclusion criteria:

1. aged above 40 years old and received cardiac surgery via median sternotomy with a stable physical condition;
2. at least met one of the frailty phenotypes, including unintentional weight loss, exhaustion, weakness, slow walking speed, and low physical activity proposed by Fried et al. (2001);
3. had clear consciousness (Mini-Mental State Examination score>24) and can communicate with Mandarin or Taiwanese;
4. consent to participate in this study.

Exclusion criteria:

1. bed-ridden, cannot stand or depends on others to complete all activities of daily living;
2. received emergency cardiac surgery;
3. with a mental illness history;
4. had exercise contraindications including: in infectious or acute phases, uncontrolled hypertension, arrhythmia, or diabetes mellitus;
5. had a musculoskeletal disease, which might be aggravated by exercise;
6. participate in phase two of cardiac rehabilitation.

One research assistant is trained for being a outcomes assessor in this study who did not know the allocation of participants.