The relationship between physical activity and heart rate variability in orthotopic heart transplant recipients

Aims and objectives. To investigate the relationship between physical activity and heart rate variability in orthotopic heart transplant recipients, to compare the difference in heart rate variability between patients one year after orthotopic heart transplant and healthy adults matched to the heart transplant recipients in terms of age, gender and physical activity levels. Background. Although physical activity affects the heart rate variability in patients with heart disease, there is a paucity of literature discussing the correlation between physical activity and heart rate variability among heart transplant recipients. Design. This was a descriptive and cross-sectional study. Methods. A total of 120 eligible subjects were divided into the orthotopic heart transplant recipient group (n=60) and the healthy adult group (n=60). The Seven-day Physical Activity Recall questionnaire was used to record the subjects' amount of physical activity per week. Heart rate variety parameters were determined by separate frequency domain components. Results. Results indicated heart transplant recipients' heart rate variety was significantly lower than that of healthy adults in terms of mean, sdr, total power (ms2), low frequency (ms2), low frequency (nu), high frequency (ms2) and low frequency/high frequency. Heart transplant recipients' heart rate variety including total power (ms2), low frequency (ms2) and high frequency (ms2) was 18.2, 2 and 7.2% of healthy controls, respectively; the amount of absolutely and relatively moderate physical activity was positively related to high frequency (ms2) and high frequency (nu), but was negatively related to low frequency/high frequency. High frequency (nu) increases while the total amount of weekly physical activity increases. Conclusions. Results confirmed that the more the moderate physical activity performed, the better the patient's heart rate variability. Relevance to clinical practice. We suggest that clinical care providers have to encourage heart transplant recipients to engage in moderate physical activity.