The impact of cardiac rehabilitation on muscle strength: a crucial element of functional capacity

Abstract Introduction Cardiac rehabilitation (CR) is defined as a multidisciplinary program encompassing exercise training, modification of cardiovascular risk factors, and psychosocial assessment. Physician-prescribed exercise is a crucial and safe component that can significantly enhance the quality of life and functional capacity. Purpose The purpose of this study is to assess whether improvements in muscular strength have an impact on functional capacity. Methods A prospective analysis of patients enrolled in a cardiac rehabilitation phase two program was conducted. Standardized forms were utilized to collect patient data, including baseline characteristics, muscle strength evaluation (upper and lower limb strength and Time Up and Go test), the six-minute walking test (6MWT), and cardiopulmonary exercise test. Descriptive and inferential statistics were performed. Results We enrolled 446 patients participating in the phase two CR program (81% male; mean age at the program's beginning was 61+/-11 years). The mean number of exercise sessions performed was 14+/-6. Among them, 85% had ischemic heart disease, 6% had valvular heart disease, and 3% had dilated cardiomyopathy. During the initial assessment, 73% of patients were in NYHA functional class II, 19% in NYHA I, and 8% in NYHA III. Forty-three percent of patients had a reduced left ventricular ejection fraction (LVEF 50%). Throughout the CR program, there was an improvement in lower limb (mean value increased from 15 Kg to 20 Kg, p=0.001), upper limb strength (mean value increased from 19 to 23 Kg, p=0.001), and in the time taken for the Up and Go test (a decrease in mean time from 14 s to 9 s, p=0.001). Patients demonstrating improvement in at least one of these parameters also showed, at the end of the programme, enhanced 6MWT mean time (from 454 to 569 meters), peak VO2 (from 15 to 17 mL/Kg/min), and the duration of cardiopulmonary stress testing (from 7:50 to 8:39) (p=0.001). In patients with reduced LVEF, there was a tendency toward enhanced 6MWT time in those who showed improvement in all the three upper and lower limb strength and in the Time Up and Go test compared with those who do not improve in all these tests (620 to 553 meters), which did not reach significance. Conclusion Strength exercise is a vital component of CR programs and can significantly contribute to improvements in functional capacity. Therefore, its practice should be emphasized to enhance overall program effectiveness. Particularly in patients with reduced ejection fraction, a global strength improvement can have a positive impact on daily life functional capacity.