Blood, sweat, tears and fibrosis: when overtraining injures the liver

The crosstalk between the skeletal muscles and the liver is receiving growing attention, as patients with chronic liver disease often develop a loss of skeletal muscle mass. In these patients, particularly those with metabolic dysfunction-associated steatotic liver disease, physical exercise improves insulin sensitivity and hepatic steatosis. However, excessive exercise may impair mitochondrial function, inflammation, and liver health. The study by Liu <i>et al</i>. demonstrates that overtraining promotes liver fibrosis through myocyte-derived small extracellular vesicles. Here, we comment on the novelty of these findings and areas to be developed in the future.