Muscle fatigability in type 2 diabetes

BACKGROUND: Patients with type 2 diabetes (T2D) may be subject to premature muscle fatigue. However, the effect of diabetes on muscle fatigability has not yet been thoroughly examined. The purpose of this study was to investigate the effect of T2D on muscle fatigability at the upper and lower body. METHODS: Thirty-three T2D patients (18 men and 15 women; mean age, 59.3 ± 5.3 years) and 34 matched healthy control participants (17 men and 17 women; mean age, 60.1 ± 6.1 years), were recruited. Clinical characteristics of diabetic patients were assessed by considering a wide range of vascular and neurological parameters in order to exclude the presence of microvascular complications and artery disease. Gender-specific muscle function was evaluated measuring the maximal voluntary isometric contraction (MVIC), and the endurance time at 50% of the MVIC at the shoulder and at the knee extensor muscles. RESULTS: Muscle strength in the upper body was similar among groups, whereas in the lower body, it was significantly reduced in T2D men (-16%) and women (-22%) compared with the controls. Additionally, the endurance time in both upper and lower body was significantly lower in T2D men (-18% and -29%) and women (-19% and -25%, respectively) than controls. CONCLUSIONS: Besides the reduction in strength, muscle dysfunction in T2D is characterized by a higher fatigability that affects both upper and lower body muscles. This effect is independent to the presence of diabetic complications and may represent a more sensitive marker of muscular dysfunction than muscle strength.