Impact of prolonged walking exercise on cardiac structure and function in cardiac patients versus healthy controls

Background and design Previous studies have demonstrated that endurance exercise can cause an acute transient decrease in cardiac function in healthy subjects. Whether this also occurs in cardiac patients is unknown. We investigated the impact of prolonged single day and three-day walking exercise on cardiac function and cardiac biomarkers between cardiac patients and healthy controls in an observational study. Methods We recruited 10 cardiac patients (nine males, one female, 685 years) and 10 age- and sex-matched healthy control subjects (nine males, one female, 684 years) to perform 30 or 40km of walking exercise per day for three consecutive days. Cardiac function was examined using echocardiography and cardiac biomarkers (cardiac troponin and B-type natriuretic peptide) with blood samples. Data were collected before walking and directly after walking on day 1 and day 3. Results Post-exercise early systolic tissue contraction velocity of the left ventricle (p=0.005) and global longitudinal left ventricle strain (P=0.026) were increased in both groups compared with baseline. Post-exercise right ventricle peak early diastolic tissue filling velocity and systolic blood pressure/left ventricle end-systolic volume ratio decreased in both groups (p=0.043 and p=0.028, respectively). Post-exercise cardiac troponin levels increased (p=0.045) but did not differ across groups (p=0.60), whereas B-type natriuretic peptide levels did not change (p=0.43). Conclusion This study suggests that stable cardiac patients are capable of performing three days of prolonged walking exercise without clinically significant acute overall deterioration in cardiac function or more pronounced increase in cardiac biomarkers compared with healthy controls.