Home-Based Exercise Improves Muscle Oxidative Capacity in Kidney Disease

Introduction: Muscle impairment in chronic kidney disease (CKD) contributes to decreased physical performance, frailty, and increased mortality. This proof-of-concept randomized controlled study evaluated the efficacy of a 12-week home-based, video-supervised exercise program on muscle endurance in moderate-to-severe nondialysis CKD. Methods: Thirty-two sedentary adults with CKD (estimated glomerular filtration rate [eGFR] < 60 ml/min per 1.73 m2) were randomized (3:1) to a home exercise group (EX, n = 23) or usual care group (UC, n = 9). The primary outcome was in vivo muscle mitochondrial bioenergetics (rate of phosphocreatine recovery, kPCr) measured using phosphorus-31 magnetic resonance spectroscopy. Secondary outcomes included 6-minute walk test (6MWT) distance (6MWD), total work, peak oxygen consumption (VO2peak), and work efficiency obtained from cardiopulmonary exercise testing (CPET). Other outcomes were body composition and plasma cytokines. Within- and between-group differences were analyzed using linear mixed models (LMMs). Results: Mean (SD) ages were 62.6 (10.8) years in EX and 67.2 (8.2) in UC. Mean eGFRs were 35.0 (12.6) and 32.3 (12.0) ml/min per 1.73 m2, respectively. No serious adverse events occurred; 90.5% of EX completed ≥ 75% of sessions. Compared with UC, EX significantly increased kPCr (0.20/min, 95% confidence interval [CI]: 0.05–0.35, P = 0.01), total work (5.03 kJ, 95% CI: 1.25–8.80, P = 0.007), and 6MWD (39.1 m, 95% CI: 7.1–71.1, P = 0.014) while preserving fat-free mass (2.3 kg, 95% CI: 0.49–4.1, P = 0.024) and marginally decreasing fat mass (−2.22 kg, 95% CI: −4.7 to 0.27, P = 0.1) . Interleukin (IL)-8 concentration differed between groups (effect size: −1.16, 95% CI: −2.4 to −0.04, P = 0.016). Work efficiency, VO2peak, and other cytokines showed no significant differences between groups. Conclusion: Home-based, video-supervised exercise is feasible, improves muscle oxidative capacity and endurance, offering a strategy to mitigate functional decline in moderate-to-severe nondialysis CKD.