The effect of low-intensity intradialytic aerobic exercise on heart rate variability in maintenance hemodialysis patients

Background: End-stage renal disease (ESRD) patients undergoing maintenance HD typically adopt a sedentary lifestyle which increases cardiometabolic risk and takes many years to be clinically detectable. Heart rate variability (HRV) is a non-invasive method to assess cardiac autonomic modulation. Interventions to increase HRV, such as exercise therapy, have been examined, given the theoretical plausibility that improvements in HRV may lead to improved outcomes. This study aimed at assessing the effects of aerobic exercise during hemodialysis sessions on the HRV of patients with ESRD. Methods: This research is a quasi-experimental study with pre and post-test randomized control group design. From the total of 20 ESRD patients undergoing maintenance HD randomly assigned to either exercise or control group, 2 subjects dropped out, leaving 18 ESRD patients. The patients in the exercise group were submitted to a low intradialytic aerobic exercise, performed during the first two hours of HD, twice weekly, for 12 weeks. At baseline and after 12 weeks, all participants underwent short-(for 5 min) term measurements of HRV. The data were analyzed in the SPSS package program. Results: There is a significant difference in post-pre changes (Δ) SDNN between the exercise and control group, but there were no significant differences in ΔRMSSD (p = 0.157) and ΔLF/HF ratio (p = 0.859), with the large effect size for ΔSDNN (Cohen’s D 1.01), medium effect size for ΔRMSSD (Cohen’s D 0.70), and very small effect size for ΔLF/HF ratio (Cohen’s D 0.09). Conclusion: Twelve weeks of supervised low-intensity intradialytic aerobic exercise has modified heart rate variability in maintenance hemodialysis patients.