1. Investigación

Background: Exercise improves the physical function of people suffering from chronic kidney disease on hemodialysis (HD). Virtual reality is a new type of intradialysis exercise that has a positive impact on physical function. Intradialysis exercise is recommended during the first 2 h, but its safety in the last part of the dialysis session is unknown. Methods: This was a pilot sub-study of a clinical trial. Several hemodynamic control variables were recorded, including blood pressure, heart rate, and intradialytic hypotensive events. These variables were recorded during three different HD sessions, one HD session at rest, another HD session with exercise during the first two hours, and one HD session with exercise during the last 30 min of dialysis. The intradialysis virtual reality exercise was performed for a maximum of 30 min. Results: During exercise sessions, there was a significant increase in heart rate (6.65 (4.92, 8.39) bpm; p < 0.001) and systolic blood pressure (6.25 (0.04,12.47) mmHg; p < 0.05). There was no difference in hemodynamic control between the sessions with exercise during the first two hours and the sessions with exercise during the last 30 min. There was no association between intra-dialytic hypotensive events at rest (five events) or exercise at any point (two vs. one event(s), respectively). Conclusion: performing exercise with virtual reality at the end of a hemodialysis session is not associated with hemodynamic instability.

It has been suggested that physical exercise in chronic hemodialysis could improve dialysis dose and reduce postdialysis rebound. A randomized controlled trial was performed to compare a group of patients doing physical exercise during the first 2 h of hemodialysis sessions and another group doing physical exercise at home. The descriptive variables, dialysis doses measured by KtV, and rebounds (urea, creatinine, potassium, phosphorus), were recorded. For 69 patients: the mean KtV was 1.84; the 30-min rebound of creatinine was 32.37%, urea 24.39%, potassium 15.31%, and phosphorus 51.29%. For each patient, the basal measurement was compared with those determined when performing physical exercise; no statistically significant differences were observed between the changes determined to dose and rebound in the group with hemodialysis exercise compared to those of the home exercise group. In conclusion, performing physical exercise during the first 2 hours of hemodialysis sessions neither lowered postdialysis molecules rebound nor improved dialysis dose.