Brisk walking or similar aerobic exercise for at least 150 minutes per week can help people with non-alcoholic fatty liver disease (NAFLD) achieve a clinically meaningful reduction in liver fat, according to a systematic review and meta-analysis published in The American Journal of Gastroenterology.
“Our findings can give physicians the confidence to prescribe exercise as a treatment for non-alcoholic fatty liver disease,” Jonathan Stine, MD, of Pennsylvania State College of Medicine, said in a press release. “Having a target amount of physical activity to aim for will be useful for health care and exercise professionals to develop personalized approaches as they help patients modify their lifestyles and become more physically active.”
Arising from the accumulation of fat in the liver, NAFLD and its more severe form, non-alcoholic steatohepatitis (NASH), are responsible for a growing proportion of advanced liver disease worldwide. Often associated with obesity and diabetes, it is also known as metabolic-associated fatty liver disease (MAFLD). Over time, fatty liver disease can lead to fibrosis, cirrhosis and even liver cancer.
With no effective approved medical therapies, NAFLD disease management depends on lifestyle changes such as weight loss and exercise. But it is unclear how much exercise is needed to achieve a therapeutic benefit. Stine, Rohit Loomba, MD, of the University of California San Diego, and colleagues evaluated the amount of exercise needed to achieve at least a 30% relative reduction in liver fat, as measured by MRI, the threshold for histologic improvement in fat accumulation, inflammation and fibrosis on a biopsy.
For the meta-analysis, the researchers analyzed results from 14 randomized controlled trials reported through March 2022. The total study population consisted of 551 individuals with NAFLD. The average age was 53 years, and the mean body mass index was 31, above the cutoff for obesity. The team compared people who got different levels of exercise and those who did not exercise.
People who exercised were three and a half times more likely to experience a 30% or greater relative reduction in liver fat compared with people who didn’t exercise. The researchers further determined that an exercise level equivalent to brisk walking for at least 150 minutes each week (750 metabolic equivalents of task) led to significant clinical improvement. However, a lower level of exercise did not produce as much improvement. While 39% of people who exercised at this level achieved a significant response, just 26% of those who exercised less did do. What’s more, response to exercise was independent of clinically significant weight loss (more than 5% of body weight).
“Exercise is a lifestyle modification, so the fact that it might match the ability of in-development therapeutics to achieve the same outcome is significant,” Stine said in the release. “Clinicians counseling patients with NAFLD should recommend this amount of activity to their patients. Brisk walking or light cycling for half an hour a day five times a week is just one example of a program that would meet these criteria.”
Click here to read the study abstract in The American Journal of Gastroenterology.
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