Myasthenia gravis (MG) is a neuromuscular disease with weakness as a cardinal symptom. Little research exists concerning aerobic or muscular resistance training in patients with MG. This study examined the effects of exercise in this population.

This prospective study included patients diagnosed with chronic MG, recruited from three outpatient neurology clinics in Sweden. The participants underwent supervised exercise sessions lasting 75 minutes and consisting of aerobic, resistance and balance training two times per week for 12 weeks. The patients were assessed before and after training with nerve conduction studies, strength and performance measures and with blood tests of serum for serum specific microRNAs, interleukin-6, muscle enzymes, CRP, and creatinine, as well as the MG Composite Score, and peak expiratory flow.

Among the 10 participants, there was no evidence of increased disease activity during the study. In the nerve conduction studies, the CMAP amplitude increased significantly in the biceps and quadriceps (P＝0.002 and P＝0.037, respectively). Proximal muscle strength significantly improved in both arm and leg muscles. Performance on the Six-Minute Walk Test and 30-Second Walk Test improved significantly (P＝0.002 and P＝0.0039, respectively). While BMI did not significantly change, body composition did, with increased muscle mass and reduced fat mass (P＝0.02). All patients scored much higher in physical activity after the study (P＝0.008). The disease-specific microRNAs, miR150-5p (P＝0.048) and miR21-5p (P＝0.0020), were significantly reduced after the training period, while muscle enzymes remained normal.

This small study of patients with chronic myasthenia gravis found that exercise training, twice per week, increased aerobic capacity, improved body composition, improved motor action potential amplitudes, and improved disease specific biomarkers.