Circulating Myostatin Decreases with Aerobic Exercise Training in Pre‐Diabetic but not Diabetic Human Subjects

Abstract

Myostatin is a potent secreted inhibitor of skeletal muscle growth. We recently demonstrated that plasma myostatin decreased with aerobic exercise and a correlation with insulin sensitivity. We subsequently quantified myostatin in plasma samples from two exercise‐training cohorts to determine the effects of both endurance and resistance exercise on circulating myostatin levels in both insulin resistant (STRRIDE, n=100) and type 2 diabetic (DARE, n=360) human subjects. In both studies, fasting myostatin levels increased significantly (P<0.05) whilst markers of insulin resistance (Si and HOMA‐IR) worsened in the control subjects (~ 6 months sedentary). In the STRRIDE cohort the most intense aerobic exercise group (65–80% VO2, 2200 kcal/week) showed the most significant decrease in plasma myostatin. There were no significant decreases in plasma myostatin in the aerobic and combined exercise training groups in the DARE cohort, however, there was a small but significant decrease in resistance training group. These findings confirm that plasma myostatin levels are responsive to exercise training in both insulin resistant and diabetic patients albeit to different exercise modalities. These findings support our hypothesis that myostatin is in the causal pathway of acquired insulin resistance with physical inactivity.