Characteristics of physical activity and sedentary behavior in patients undergoing outpatient cardiac rehabilitation

Cardiac rehabilitation is crucial for the secondary prevention of cardiovascular disease, the leading cause of death worldwide. In Japan, as hospitalization periods have been shortened due to advances in medical technology and government policies, outpatient rehabilitation focused on lifestyle and physical activity (PA) is becoming increasingly important as hospital stays shorten. This study was aimed to identify patient characteristics that define the different types of PA and sedentary behaviors, and patient factors in 92 Japanese outpatients by using accelerometers. The patients were found to spend considerable time being sedentary (663.7 ± 118.1 min/day) and very little time engaging in moderate-to-vigorous PA (MVPA, 25.6 (10.6-43.4) min/day). Regression analysis revealed that the daily duration of sedentary behavior was 64 min longer in men than in women (β = 64.2, 95% CI[12.9, 115], p = 0.015); furthermore, men engaged in 22% less light PA (β = -0.245, 95% CI[-0.388, -0.102], p = 0.001). Additionally, MVPA increased by 43% for every 1 metabolic equivalent (MET) task increase in the anaerobic threshold (AT) (β = 0.367, 95% CI[0.035, 0.698], p = 0.031) but decreased by 3% per year of age(β = -0.035, 95% CI[-0.056, -0.015], p < 0.001). The study also found that body mass index (BMI) was negatively correlated with walking time (β = -0.039, 95% CI[-0.075, -0.003], p = 0.036), while AT was positively correlated with MVPA (β = 0.367, 95% CI[0.035, 0.698], p = 0.031) but negatively correlated with time above the AT (β = -2.06, 95% CI[-2.53, -1.59], p < 0.001). These results emphasize the importance of customizing rehabilitation programs according to sex, age, BMI, and AT differences. Furthermore, monitoring home activities and providing individualized prescriptions may enhance the effectiveness of rehabilitation programs.