The condition is characterized by fat accumulation in liver cells without a clear cause, such as alcohol use. It may progress to inflammation, cirrhosis, and liver failure. NAFLD is associated with unhealthy lifestyle behaviors. This includes overeating, an unhealthy diet, and lack of exercise.
A study out of Japan recorded that NAFLD affects 41% of all men in the country. Out of this population, 25% will progress to non-alcoholic steatohepatitis (NASH) and hepatic dysfunction.
“We compared data from obese Japanese men with NAFLD on a 3-month exercise regimen with those on dietary restriction targeting weight loss,” senior author Professor Junichi Shoda explains. “We tracked hepatic parameters, reduction in adipose tissue, increase in muscle strength, reductions in inflammation and oxidative stress, changes in organokine concentrations, and expression of target genes of Nrf2, an oxidative stress sensor.”
It was found that exercise helped muscle mass to stabilize while decreasing body fat and mass. Ultrasound results showed that an exercise regime reduced liver steatosis by 9.5%, liver stiffness by an additional 6.8%, and the FibroScan-AST Score (a measure of liver fibrosis) by an additional 16.4% over just a weight-loss regimen.
Exercise was also shown to induce anti-inflammatory and anti-oxidative stress responses by altering the circulating concentrations of specific organokines, which activated an oxidative stress sensor. It also showed the promise of maintaining liver function by enhancing phagocytic capacity.
A Relationship between Exercise and Liver Health
The findings clearly showed a relationship between exercise and a reduction of liver steatosis and fibrosis in NAFLD. This is achieved through the preservation of muscle mass and is independent of weight changes.
Researchers warn that patients on an exercise program may become demotivated and drop out if they do not experience significant weight loss. They suggest moderate to vigorous-intensity exercise should be integrated into NAFLD therapeutic regimens. This can help ensure the patient sees results and becomes more motivated to continue with the exercise program.
By incorporating an exercise component into NAFLD therapy, researchers believe the incidence of inflammation, cirrhosis, and liver failure can be reduced. Although this study comes from Japan, it can help with suggested therapy in the United States.
Here in the U.S, NAFLD is the most common form of chronic liver disease, affecting about one-quarter of the population. More research is needed to confirm these findings in this population, but this study gives an overall view of how important exercise can be for liver disease.