What Is the Optimal Timing for Intradialytic Resistance Exercise? A Randomized Controlled Trial

Abstract

Objective: This study aimed to examine the impact of intradialytic resistance exercise timing on blood pressure, physical performance, and muscle strength in patients on hemodialysis.

Design: A single-blind, randomized controlled clinical trial.

Setting: Hospital-based hemodialysis unit.

Participants: Forty-two patients (N=42) on hemodialysis were randomly assigned to early- or late-exercise groups.

Interventions: Both groups performed the same resistance exercise protocol during either the first or last 2 hours of dialysis for 8 weeks.

Main outcome measures: The primary outcomes were postdialysis systolic blood pressure and the number of intradialytic hypotensive episodes. Secondary outcomes included physical performance and lower extremity muscle strength.

Results: Postdialysis systolic blood pressure declined less in the late-exercise group than in the early exercise group (interaction effect: -5.4 mmHg; 95% CI, -10.72 to -0.25; P<.05). No significant difference in the number of intradialytic hypotensive episodes was observed between the groups (P>.05). Both groups showed significant improvements in blood pressure, heart rate, and physical performance (P<.05). Significant improvement was observed only in the left quadriceps femoris muscle in both groups (P<.05).

Conclusions: Resistance exercise performed in the final 2 hours of dialysis is as safe and effective as that performed earlier. The smaller reduction in postdialysis systolic blood pressure in the late-exercise group may suggest a time-related clinical benefit.

Keywords: Blood pressure; Hemodialysis; Rehabilitation; Resistance exercise time.