Exercise cycling during hemodialysis (HD) sessions may reduce left ventricular mass and improve other cardiovascular parameters compared with usual care, a new study finds.

In the CYCLE-HD trial, investigators randomly assigned 130 patients from 3 dialysis centers in the United Kingdom to usual care (control group) or a 6-month progressive cycling program. Cycling was performed 3 times per week during dialysis with the goal of 30 minutes of continuous cycling at a rate of perceived exertion of 12 to 14, with resistance adjustments as needed. Of the 130 patients, 101 completed the trial protocol: 51 in the exercise group and 50 in the control arm.

Over 6 months, left ventricular mass as measured by cardiac magnetic resonance imaging (MRI) declined by a significant 11.1 g in the exercise group, whereas it increased slightly in the control group, James O. Burton, DM, MBChB, of the University of Leicester in the United Kingdom and colleagues reported in Kidney International. Intradialytic cycling also significantly improved secondary outcomes associated with beneficial left ventricular remodeling, including native T1 mapping (–32.23 ms) and aortic pulse-wave velocity (–2.07 ms-1).

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“Taken together, these data suggest [intradialytic cycling]improves the cardiovascular health of patients on maintenance hemodialysis,” Dr Burton’s team wrote.

Intradialytic cycling did not significantly improve physical function or quality of life over 6 months. The investigators discussed a myriad of factors that may account for the cardiovascular improvements. Whether intradialytic cycling confers a survival benefit requires further study, they acknowledged.

Serious adverse events occurred in more patients in the intervention than control group (37 vs 14 patients, respectively) but none were considered related to the exercise. The investigators reported no increase in either ventricular ectopic beats or complex ventricular arrhythmias as a result of exercise. Approximately 11% of the intervention group had ischemic heart disease.

A large proportion of patients declined to participate in the exercise trial, the investigators reported. Participants completed fewer exercise sessions over time (76.7% for month 1 compared with 61.4% for month 6) for reasons such as malaise and pain. They also had a shorter duration of exercise over time (41.1 minutes in month 1 compared with 37.7 minutes in month 6), although they maintained exercise intensity. The mean age of the exercise group was slightly younger than that of the control group (55.5 vs 58.9 years).


Graham-Brown MPM, March DS, Young R, et al. A randomized controlled trial to investigate the effects of intra-dialytic cycling on left ventricular mass. Kidney Int. 2021 Jun;99(6):1478-1486. doi:10.1016/j.kint.2021.02.027