Functional training added to intradialytic cycling lowers low-density lipoprotein cholesterol and improves dialysis adequacy: a randomized controlled trial

Background Exercise has various positive effects on hemodialysis patients. However, there is no clear evidence which type of exercise yields better results. This study aimed to determine the effects of guided functional training added to the intradialytic cycling on dialysis adequacy and biochemical parameters in hemodialysis patients. Additionally, we aimed to investigate if patients could transfer functional exercise to an unsupervised home environment and retain gained improvements. Methods Randomization was done to a functional training intervention group (INT) (n = 20) or intradialytic cycling control group (CON) (n = 20). The INT attended a pre-dialysis functional training in the first 8 weeks. In the second 8 weeks, they performed functional exercises at unsupervised home environment on non-dialysis days. During the whole study, both groups participated in the intradialytic cycling program. Results Both groups demonstrated a significant increase in dialysis adequacy (Kt/V) in the eight (0.15, 95% CI 0.06 to 0.24;p = 0.003 for INT and 0.21, 95% CI 0.11 to 0.3;p < 0.001 for CON) and the 16th study week (0.13, 95% CI 0.03 to 0.24;p = 0.017 for INT and 0.13, 95% CI 0.03 to 0.22;p = 0.013 for CON) compared to their baseline values with no significant between-group differences. At week eight, the total cholesterol was significantly lowered in the INT (- 0.34 mmol/L, 95% CI - 0.6 to - 0.07;p = 0.016) and remained lower at week 16 (- 0.32 mmol/L, 95% CI - 0.64 to - 0.01;p = 0.049) with no significant changes in the CON. Low-density lipoprotein levels in the INT were significantly reduced after 8 weeks (- 0.35 mmol/L, 95% CI - 0.64 to - 0.06;p = 0.022) and remained reduced after 16 weeks (- 0.28 mmol/L, 95% CI - 0.52 to - 0.03;p = 0.030). There were no significant differences found for albumin, high-density lipoprotein cholesterol, triglycerides, C-reactive protein, and hemoglobin in both groups. Conclusions We demonstrated that functional training added to intradialytic cycling improved lipid profile and dialysis adequacy. Additionally, the effects of the unsupervised, home-based program were preserved during the second study phase. This study supports the assumption that combined training is more effective compared to solely intradialytic exercise.