How Much Exercise is Best for Nonalcoholic Fatty Liver Disease?

New research finds that moderate and vigorous exercise are equally effective in reducing fatty liver content, which the study authors say is positive news for patients with nonalcoholic fatty liver disease (NAFLD).

In order to compare the effects of both moderate and strenuous exercise on intrahepatic triglyceride content and metabolic risk factors among patients with NAFLD, investigators conducted a randomized clinical trial that included participants with central obesity and NAFLD. Patients were recruited from community-based screening in Xiamen, China, from December 1, 2011, through December 25, 2013.
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The 220 patients were divided into 3 groups, with each cohort assigned different levels of exercise for 1 year. A "vigorous-moderate" exercise group jogged 150 minutes a week at 65% to 80% of their maximum heart rate for the first 6 months, followed by 150 minutes of brisk walking at 45% to 55% of their maximum heart rate for the other half of the year. A second group walked briskly for 150 minutes weekly for 1 year, while the third group did not exercise at all.

In following up at the 6-month mark, the researchers found that intrahepatic triglyceride content was reduced by 5% in the vigorous-moderate group and 4.2% in the moderate exercise group compared with the control group.

In addition, body weight, waist circumference, and blood pressure were significantly reduced in the vigorous-moderate exercise group compared with the moderate exercise and control groups at the 6-month assessment, and in the vigorous-moderate and moderate exercise groups compared with the control group at the 12-month assessment. Body fat was also significantly reduced in the vigorous-moderate exercise group compared with the moderate exercise and control groups at the 12-month assessment, according to the authors.

Overall, the findings "indicated that moderate and vigorous exercise programs have similar effects on liver fat reduction among obese patients with nonalcoholic fatty liver disease," said Jiang He, MD, coauthor of the study and a professor in the Department of Epidemiology at Tulane University School of Public Health and Tropical Medicine in New Orleans, Louisiana.

These results support the current physical activity guidelines that recommend 150 minutes of moderate-intensity activity per week for the management of nonalcoholic fatty liver disease, Dr He said. "Because moderate exercise is more sustainable and provides most of the benefit of vigorous exercise, it should be recommended for the prevention and treatment of nonalcoholic fatty liver disease, especially for individuals who might have difficulty engaging in vigorous exercise."

—Mark McGraw

Reference

Zhang H-J, He J, Pan L-L, et al. Effects of moderate and vigorous exercise on nonalcoholic fatty liver disease: a randomized clinical trial [published online July 5, 2016]. JAMA Intern Med. doi:10.1001/jamainternmed.2016.3202.