Influence of increased physical activity without body weight loss on hepatic inflammation in patients with nonalcoholic fatty liver disease

BACKGROUND: Physical activity (PA) that includes an accumulated exercise regimen that meets or exceeds a certain intensity reduces intrahepatic fat, leading to the improvement of nonalcoholic fatty liver disease (NAFLD) in afflicted patients. However, whether an increase in comprehensive PA, including activities of daily living, contributes to ameliorating the pathophysiology of NAFLD remains unclear. This study aimed to examine whether PA improves liver function in patients with NAFLD. METHODS: The study included 45 patients with NAFLD who underwent follow-up examinations at least 6 months—but no later than 1 year—after their baseline examinations. The patients were interviewed about their daily activities and exercise habits to determine whether they had engaged in at least 3 metabolic equivalents (METs) per day during the previous 6 months; the quantity of PA, expressed in Ekusasaizu (Ex) units, was calculated as METs multiplied by hours. Patients who had achieved at least a 1-Ex increase in PA per week compared to baseline at the time of their follow-up interview (the PA increase group) were compared to those whose PA was the same or lower at the time of follow-up (the PA non-increase group). RESULTS: There were no significant changes in all blood and biochemical parameters in the PA non-increase group at the time of follow-up when compared with baseline levels. In the PA increase group, aspartate aminotransferase, alanine aminotransferase, and γ-guanosine triphosphate levels were all significantly lower at follow-up than they were at baseline. Body weight did not change significantly from baseline to follow-up in both groups. CONCLUSIONS: In the present study, hepatic inflammation improvement was accompanied by increased PA but not decreased body weight. Increasing PA may be effective for the improvement of hepatic inflammation even without body weight loss. Our results indicate the effectiveness of PA monitoring for the management of NAFLD. TRIAL REGISTRATION: UMIN-CTR, UMIN000038530