Effects of Aerobic Versus Resistance Training on Bone Metabolism in Stage 3-4 Chronic Kidney Disease

Effects of Aerobic Versus Resistance Training on Bone Metabolism in Stage 3-4 Chronic Kidney Disease: A Randomized Controlled Trial

This randomized controlled trial investigates the comparative effects of aerobic versus resistance training on bone mineral density (BMD) and bone metabolism markers in patients with stage 3 or 4 chronic kidney disease (CKD). The primary aim is to evaluate the impact of two distinct exercise modalities on serum osteoprotegerin (OPG), receptor activator of nuclear factor kappa-B ligand (RANKL), and the OPG/RANKL ratio, as well as densitometric changes at key skeletal sites.

Chronic kidney disease-mineral and bone disorder (CKD-MBD) is a common complication in non-dialysis CKD patients, driven by disrupted calcium-phosphate metabolism, secondary hyperparathyroidism, and altered bone remodeling pathways, such as the OPG-RANKL axis. Exercise is an emerging non-pharmacological strategy to mitigate skeletal deterioration in CKD, yet the differential effects of aerobic and resistance training on bone health remain poorly understood in this population.

This study recruited 60 CKD patients (stage 3-4, aged 30-50 years) and randomly allocated them into two groups (n=30 each): a resistance training group and an aerobic exercise group. Both groups underwent supervised exercise 3 times per week for six months. Bone mineral density was assessed using dual-energy X-ray absorptiometry (DEXA) at the lumbar spine (L2-L4), femoral neck, and distal radius. Serum concentrations of OPG and RANKL were measured via ELISA at baseline and post-intervention.

Inclusion Criteria:

• Adults aged 30 to 50 years
• Diagnosed with stage 3 or 4 chronic kidney disease (non-dialysis dependent)
• BMI between 20 and 24 kg/m²
• Not currently taking medications that affect bone density (e.g., corticosteroids, bisphosphonates)
• Non-smokers and abstinent from alcohol
• Not receiving hormone replacement therapy
• Willing and able to participate in supervised exercise sessions for 6 months

Exclusion Criteria:

• Diagnosis of type 1 diabetes mellitus
• Uncontrolled hypertension
• History of cardiovascular, musculoskeletal, endocrine, or metabolic bone disease
• Pregnant or planning pregnancy during the study period
• Participation in a structured exercise program within the last 3 months
• Contraindications to exercise as determined by medical evaluation
• Use of investigational drugs or enrollment in another clinical trial during the study period