The liver plays a crucial role in numerous metabolic processes necessary to leading a healthy life, including those essential to metabolism, such as storing energy and regulating blood sugar. Exercise has been shown to improve liver health by reducing fat in the liver, improving insulin sensitivity, reducing inflammation, boosting the immune system and improving mental health. The great news here is that it doesn’t matter what type of exercise you choose to perform — any exercise is beneficial for the liver, and exercise prescription can be tailored to meet individual needs and preferences. That means that as an exercise professional, you can incorporate aerobic training, resistance training, high-intensity interval training (HIIT), low-impact HIIT and more. Several studies have even looked at the impact of yoga and Pilates on liver health, and although the results are mixed, in the right setting these may also provide benefit.
Nonalcoholic fatty liver disease (NAFLD) is the leading cause of liver disease and, in parallel with the obesity pandemic, now affects one out of three adults worldwide. NAFLD occurs when there is abnormal accumulation of fat in the liver not caused by alcohol consumption. NAFLD has been linked to obesity, insulin resistance and physical inactivity, and it can progress to a more severe form of liver disease called nonalcoholic steatohepatitis (NASH). Over time, NASH can lead to cirrhosis or liver cancer, which in some cases may require a lifesaving liver transplantation.
While many factors lead to the development of NAFLD, physical inactivity plays a major role. In light of this, the American College of Sports Medicine® (ACSM) held a roundtable discussion on NAFLD and physical activity in summer 2022. The roundtable brought together experts in the fields of hepatology, exercise physiology and behavioral health. The roundtable discussion highlighted the importance of physical activity in the prevention and treatment of NAFLD, finding that patients with NAFLD who exercise regularly can expect a number of benefits to liver health, including a reduction in liver fat accumulation, improved histologic disease activity, favorably changing body composition, improved glycemic control and lowered cardiovascular risk. Importantly, many of these findings can be expected without significant weight loss.
The roundtable group reached a consensus, recommending that individuals with NAFLD should engage in regular physical activity, ideally for at least 150 minutes per week of moderate-intensity aerobic exercise, such as brisk walking, or 75 minutes of vigorous-intensity aerobic exercise, such as jogging or cycling. Resistance training can be considered two days a week in order to improve muscle mass and strength. The experts also discussed the potential benefits of HIIT in individuals with NAFLD, and preliminary data suggests HIIT is as effective as either moderate- or vigorous-intensity aerobic exercise training. The roundtable faculty also acknowledged that individuals with NAFLD face many barriers to completing regular physical activity, including fatigue, joint pain and a lack of time. Exercise prescriptions that include a gradual progression of exercise, starting with low-impact activities and incorporating rest periods, may be beneficial to help remove these barriers and improve adherence.
Exercise is a great way to address NAFLD and its associated metabolic conditions, including obesity, diabetes, hypertension and more. By reducing liver fat and improving overall health, exercise may help prevent complications of liver disease and can improve quality of life. All patients with NAFLD should be encouraged to be as physically active as they can be!
Dr. Jonathan Stine is an Associate Professor of Medicine and Public Health Science at Penn State. As an internationally recognized liver expert with a research and clinical focus on nonalcoholic fatty liver disease (NAFLD) and exercise, he has authored more than 90 peer-reviewed papers, including multinational consensus guidelines. Stine is the recipient of multiple research grants and awards from the American Association for the Study of Liver Diseases, American Cancer Society and National Institutes of Health. Dr. Stine is the NAFLD consultant to the American College of Sports Medicine’s Exercise is Medicine initiative and recently co-chaired the International Roundtable on NAFLD and Physical Activity for ACSM. Dr. Stine serves as the Fatty Liver Program Director as well as the Liver Center Research Director for Penn State.
