Effects of muscle strength training with blood flow restriction on glomerular function in people with stage 3 chronic kidney disease.

Introduction: Stage 3 chronic kidney disease (CKD) represents a critical juncture in clinical management. However, muscle strength training (MST) combined with blood flow restriction (BFR) has shown benefits as an adjunctive treatment, but its renal effects remain unclear.

Objective: To analyze the effects of MST+BFR on markers of glomerular function in individuals with CKD-3.

Method: A randomized, longitudinal clinical trial with 40 participants divided into 4 groups: control (G1); low-load MST (G2); high-load MST (G3); and low-load MST combined with BFR (G4). Serum creatinine, cystatin C, microalbuminuria, and estimated eGFR were used as dependent variables. The MST protocol was conducted over 12 weeks, 3 times per week, for 30-40 minutes, with 3 exercises (single- and multi-joint) per day at progressive intensities. Data analysis (intention-to-treat) was performed using the Shapiro-Wilk test (normality), paired t-test/Wilcoxon test (within-group comparisons), ANOVA/Kruskal-Wallis tests (between-group comparisons), Bonferroni test (post hoc corrections), and Cohen's d (effect size) with a p-value ≤ 0.05.

Results: The participants were predominantly male (52.5%) with low levels of physical activity (60%), hypertension (87.5%), and some with diabetes (37.5%). Group 4 showed a significant increase in albuminuria levels (p = 0.048), as well as significant differences compared with Group 1 (creatinine, p = 0.032) and Group 2 (creatinine, p = 0.036; and eGFR-Cr, p = 0.032).

Conclusion: MST+BFR was not associated with severe adverse effects on serum creatinine/cystatin C levels, eGFR estimates, or urinary creatinine and microalbuminuria levels, but it may significantly increase albuminuria levels.