Exercise improves fitness, blood pressure, and depression in haemodialysis patients

Aerobic exercise showed the strongest evidence: it significantly increased cardiorespiratory fitness (VO2 peak improved by 2.07 units; 95% CI 0.42–3.72), improved dialysis adequacy measured by Kt/V (0.08 point gain; 95% CI 0.00–0.15), and reduced systolic blood pressure by 10 points on average (95% CI –16.35 to –3.78). Aerobic exercise also reduced inflammation markers (C-reactive protein fell by 3.28 units; 95% CI –4.68 to –1.88) and depression symptoms (standardised mean difference –0.93; 95% CI –1.32 to –0.55). Resistance exercise particularly enhanced physical performance on the six-minute walk test and improved quality-of-life scores, while combined aerobic and resistance training offered broader benefits across fitness, blood pressure, and mental health. However, most outcomes were rated low or very low certainty by GRADE criteria, meaning larger, better-designed trials are needed to confirm effects. Neither aerobic nor resistance exercise significantly altered diastolic blood pressure, mental quality of life, or phosphorus levels.

The review's heterogeneity reveals important trade-offs: aerobic exercise's systolic blood pressure reduction (–10 points) mirrors benefits seen in non-dialysis hypertension studies, but diastolic pressure showed no consistent change across meta-analyses, suggesting incomplete blood pressure control. Depression reduction (effect size –0.93) compares to moderate antidepressant efficacy in observational kidney disease cohorts. Resistance training's six-minute walk test gain (68.5 metres) represents clinically meaningful mobility improvement—roughly equivalent to a 15–20% increase in walking endurance. Combined training emerged strongest for mental and physical quality of life, improving both PCS and MCS simultaneously, a pattern not seen with aerobic or resistance alone. Notably, none of the exercise types consistently improved serum phosphorus despite its link to cardiovascular risk in dialysis patients, and Kt/V gains from aerobic exercise were modest (0.08 points, borderline statistically significant). The umbrella review methodology itself is a limitation: it summarises existing meta-analyses rather than raw trial data, potentially masking small-study bias or publication bias buried in the underlying studies.