Effects of acute intradialytic exercise on cardiovascular responses in hemodialysis patients

Background: In patients with kidney failure requiring hemodialysis (HD) treatment, intradialytic exercise (IDEX) has been advocated for its feasibility and effectiveness in improving important health outcomes. However, IDEX as an adjunct therapeutic strategy is infrequently implemented, in part due to potential risks of IDEX, especially in patients with chronic volume overload. This study was performed to evaluate the safety of IDEX performed at different time points by examining its effect on intradialytic cardiovascular hemodynamics. Methods: In a randomized cross-over study (n=12), intradialytic changes in brachial, aortic, and cardiac hemodynamics and autonomic function were examined during a HD session; (1) without exercise; (2) with 30 min of IDEX performed in the first hour of treatment; or (3) with 30 min of IDEX in the third hour of treatment. Results: IDEX during either the first or third hour did not exacerbate hemodynamic instability during treatment regardless of patient's hydrations status. While there were transient increases in stroke volume, cardiac output, and heart rate during IDEX, intradialytic changes in brachial and aortic blood pressure, cardiac hemodynamics, and autonomic function were similar on days with and without IDEX. Conclusion: These results indicate that IDEX does not exacerbate hemodynamic instability during HD, regardless of a patient's hydration status or the timing of exercise.