Resistance training to counteract the catabolism of a low-protein diet in patients with chronic renal insufficiency - A randomized, controlled trial

Background: Chronic renal insufficiency leads to muscle wasting, which may be exacerbated by low-protein diets prescribed to delay disease progression . Resistance training increases protein utilization and muscle mass. Objective: To determine the efficacy of resistance training in improving pr otein utilization and muscle mass in patients with chronic renal insufficie ncy treated with a low-protein diet. Design: Randomized, controlled trial. Setting: Tufts University, Boston, Massachusetts. Patients: 26 older patients with moderate renal insufficiency (17 men, 9 wo men) who had achieved stabilization on a low-protein diet. Intervention: During a run-in period of 2 to 8 weeks, patients were instruc ted and their adherence to the low-protein diet (0.6 g/kg of body weight pe r day) was evaluated. They were randomly assigned to a low-protein diet plu s resistance training (n = 14) or a low-protein diet alone (n = 12) for 12 weeks. Measurements: Total body potassium, mid-thigh muscle area, type I and II mu scle-fiber cross-sectional area, and protein turnover. Results: Mean protein intake was 0.64 +/- 0.07 g/kg per day after stabiliza tion. Total body potassium and type I and II muscle-fiber cross-sectional a reas increased in patients who performed resistance training by a mean (+/- SD) of 4% +/- 8%, 24% +/- 31%, and 22% +/- 29%, respectively, compared wit h those who did not. Leucine oxidation and serum prealbumin levels also imp roved significantly. Patients assigned to resistance training maintained bo dy weight compared with those who were not. Improvement in muscle strength was significantly greater with resistance training (32% +/- 14%) than witho ut (-13% +/- 20%) (P < 0.001). Conclusion: By improving muscle mass, nutritional status, and function, res istance training seems to be effective against the catabolism of a low-prot ein diet and uremia in patients with renal failure.