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

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.