A single-blind randomized controlled trial to evaluate the effect of 6 months of progressive aerobic exercise training in patients with uraemic restless legs syndrome

Abstract

Background: Uraemic restless legs syndrome (RLS) affects a significant proportion of patients receiving haemodialysis (HD) therapy. Exercise training has been shown to improve RLS symptoms in uraemic RLS patients; however, the mechanism of exercise-induced changes in RLS severity is still unknown. The aim of the current randomized controlled exercise trial was to investigate whether the reduction of RLS severity, often seen after training, is due to expected systemic exercise adaptations or it is mainly due to the relief that leg movements confer during exercise training on a cycle ergometer. This is the first randomized controlled exercise study in uraemic RLS patients.

Methods: Twenty-four RLS HD patients were randomly assigned to two groups: the progressive exercise training group (n = 12) and the control exercise with no resistance group (n = 12). The exercise session in both groups included intradialytic cycling for 45 min at 50 rpm. However, only in the progressive exercise training group was resistance applied, at 60-65% of maximum exercise capacity, which was reassessed every 4 weeks to account for the patients' improvement. The severity of RLS symptoms was evaluated using the IRLSSG severity scale, functional capacity by a battery of tests, while sleep quality, depression levels and daily sleepiness status were assessed via validated questionnaires, before and after the intervention period.

Results: All patients completed the exercise programme with no adverse effects. RLS symptom severity declined by 58% (P = 0.003) in the progressive exercise training group, while a no statistically significant decline was observed in the control group (17% change, P = 0.124). Exercise training was also effective in terms of improving functional capacity (P = 0.04), sleep quality (P = 0.038) and depression score (P = 0.000) in HD patients, while no significant changes were observed in the control group. After 6 months of the intervention, RLS severity (P = 0.017), depression score (P = 0.002) and daily sleepiness status (P = 0.05) appeared to be significantly better in the progressive exercise group compared with the control group.

Conclusion: A 6-month intradialytic progressive exercise training programme appears to be a safe and effective approach in reducing RLS symptom severity in HD patients. It seems that exercise-induced adaptations to the whole body are mostly responsible for the reduction in RLS severity score, since the exercise with no applied resistance protocol failed to improve the RLS severity status of the patients.

Trial registration: ClinicalTrials.gov NCT00942253.

Keywords: depression; exercise with no resistance; haemodialysis; sleep disorder; sleep quality.