Exercise training attenuates insulin resistance and improves beta-cell function in patients with systemic autoimmune myopathies: a pilot study

Introduction/objectives To assess the effects of exercise training on insulin resistance and beta-cell function in patients with systemic autoimmune myopathies (SAMs). Method This quasi-experimental, prospective study includes 9 patients with SAMs (six with dermatomyositis, two with antisynthetase syndrome, and one with polymyositis). Patients were submitted to a 12-week, twice a week, exercise training program comprising aerobic and resistance exercises. Baseline and after the intervention, we evaluated disease status, aerobic capacity, muscle strength, body composition, insulin resistance, and beta-cell function parameters. Results The patients have a mean age of 46.7 years and stable disease. No clinical or laboratory parameter impairment was observed after the intervention. Compared with baseline, aerobic capacity, muscle strength, and function increased after 12 weeks (P < 0.05), while no changes were observed for body composition. Data from the oral glucose tolerance test showed that exercise did not change glucose area under the curve (AUC), whereas insulin and C-peptide AUC decreased significantly (P < 0.05). Furthermore, Matsuda index and HOMA2 percentage (both surrogates of insulin resistance) also improved (P < 0.05). Conclusion Exercise training improved aerobic capacity, muscle strength, and muscle function in patients with SAMs. In addition, exercise training led to an attenuation of insulin resistance and improvements in beta-cell function parameters. These data indicate that exercise training can mitigate metabolic impairments, attenuating the cardiovascular risk in SAMs. (AU)