Effect of Exercise on Myosteatosis in Adults: A Systematic Review and Meta-Analysis

Muscle tissue typically contains only small amounts of adipose tissue, and the excess deposition of adiposity is considered a pathological phenomenon termed myosteatosis. Several studies have assessed the effects of exercise alone on the severity of myosteatosis, and some studies have reported promising results. We performed a systematic review and meta-analysis to investigate the effects of exercise interventions on myosteatosis (i.e., lipid infiltration and muscle radiation attenuation). Studies were identified through a systematic search of three databases and limited to randomized controlled trials (RCTs) focused on evaluating the effect of exercise interventions on lipid infiltration and/or muscle attenuation in adults. Thirteen studies met the inclusion criteria, and 12 were included in the meta-analysis (n = 465, 84.7% women). The volume of lipid infiltration was decreased in the exercise group compared with the control group [Hedges g = -0.45, 95% confidence interval (CI), -0.74 to -0.16; P = 0.008, I2 = 0%], and the degree of muscle radiation attenuation was increased (Hedges g = 0.67, 95% CI, 0.22 to 1.13; P = 0.009, I2 = 59.3%). Based on meta-regression analyses, there were no significant effects of mean age at baseline (lipid infiltration, b = -0.008, 95% CI, -0.035 to 0.019; P = 0.495; muscle radiation attenuation, b = -0.013, 95% CI, -0.036 to 0.011; P = 0.248) and intervention duration (lipid infiltration, b = -0.008, 95% CI, -0.028 to 0.010; P = 0.311; muscle radiation attenuation, b = -0.018, 95% CI, -0.050 to 0.014; P = 0.230) on the effect size estimates. Overall, our findings indicate that exercise can significantly improve muscle quality in populations at risk of developing obesity and sarcopenia-related disability. © 2021 the American Physiological Society