Effect of resistance training on non-alcoholic fatty-liver disease a randomized-clinical trial

Abstract

Aim: To evaluate the effect of resistance training (RT) on non alcoholic liver disease (NAFLD) patients.

Methods: A randomized clinical trial enrolling NAFLD patients without secondary liver disease (e.g., without hepatitis B virus, hepatitis C virus or excessive alcohol consumption). Patients were randomly allocated either to RT, three times weekly, for 3 mo or a control arm consisting of home stretching. The RT included leg press, chest press, seated rowing, latissimus pull down etc. with 8-12 repetitions, 3 sets for each exercise, for a total duration of 40 min. Hepatic ultrasound, fasting blood tests, anthropometrics and body composition by dual energy X-ray absorptiometry were assessed. At baseline and follow-up, patients filled out a detailed semi-quantitative food frequency questionnaire reporting their habitual nutritional intake. Steatosis was quantified by the hepatorenal-ultrasound index (HRI) representing the ratio between the brightness level of the liver and the right kidney. The HRI has been previously demonstrated to be highly reproducible and was validated against liver biopsy and proton magnetic resonance spectroscopy.

Results: Eighty two patients with primary NAFLD were randomized to receive 3 mo of either RT or stretching. After dropout or exclusion from analysis because of protocol violation (weight change > 3 kg), thirty three patients in the RT arm and 31 in the stretching arm completed the study per protocol. All baseline characteristics were similar for the two treatment groups with respect to demographics, anthropometrics and body composition, blood tests and liver steatosis on imaging. HRI score was reduced significantly in the RT arm as compared to the stretching arm (-0.25 ± 0.37 vs -0.05 ± 0.28, P = 0.017). The RT arm had a significantly higher reduction in total, trunk and android fat with increase in lean body mass. There was no correlation between the reduction in HRI in the RT arm and weight change during the study, but it was positively correlated with the change in trunk fat (r = 0.37, P = 0.048). The RT arm had a significant reduction in serum ferritin and total cholesterol. There was no significant difference between arms in dietary changes and these did not correlate with HRI change.

Conclusion: Three months RT improves hepatic fat content accompanied by favorable changes in body composition and ferritin. RT may serve as a complement to treatment of NAFLD.

Keywords: Abdominal fat; Nutrition; Obesity; Physical activity; Resistance exercise.

Figure 1

Flow chart of trial participants. ¹Excluded from analysis due to > 3 kg weight change. RT: Resistance training; NAFLD: Non alcoholic liver disease.

Figure 2

Change (absolute) in hepatorenal-ultrasound index values between baseline and end of trial by treatment arm. A: Resistance arm; B: Stretching arm. Each line represents a single patient. HRI: Hepatorenal-ultrasound index.

Figure 3

Change (absolute) in body composition parameters between baseline and end of trial by treatment arm. P represents the significance of difference between resistance and stretching arm for each parameter (n = 55). LBM: Lean body mass.