Effect of Exercise Training on Liver Steatosis in Adults with Obesity and Nonalcoholic Fatty Liver Disease

Abstract

Non-Alcoholic Fatty Liver Disease (NAFLD) is the leading cause of chronic liver disease worldwide. It is characterized by hepatic steatosis and can progress to fibrosis, cirrhosis, and hepatocellular carcinoma. NAFLD is associated with the obesity epidemic and comorbidities such as hyperlipidemia and type 2 diabetes mellitus, primarily affecting middle-aged men and postmenopausal women, although its prevalence is rapidly increasing among younger individuals. Current pharmacological treatment focuses on managing comorbidities, such as cardiovascular and metabolic dysfunctions, rather than directly addressing the liver disease itself. Lifestyle interventions, including diet and exercise, have been shown to be effective in managing steatosis and preventing its progression to cirrhosis. This review aims to synthesize studies examining the effects of various exercise protocols on hepatic steatosis in obese adults and to provide guidelines regarding the type and intensity of exercise for managing steatosis in this population. The results indicated a reduction in steatosis of 10,7% over 16 weeks with the implementation of aerobic training for 45-60 minutes at 60% of heart rate reserve (HRR) or 55% of maximum oxygen uptake (VO2max), with a training frequency of five times a week. Additionally, reductions of 1-3% in steatosis were observed with both aerobic and high-intensity interval training protocols, as well as resistance exercise, at a training frequency of 3-4 times per week over durations of 4, 8 and 12 weeks, and up to 8 months. In conclusion, exercise can lead to significant improvements in hepatic steatosis in obese adults, with an emphasis on daily aerobic exercise. Further research is needed to explore the effects of different exercise protocols concerning intensity and duration to gain additional insights.