AIM: To study the effect of regular aerobic exercise on insulin resistance, serum aminotransferase and liver histology in nonalcoholic fatty liver disease (NAFLD) patients.

METHODS: Sixty (mean age 40.0±8.5 years, 75% male) NAFLD patients were included in the study. After baseline anthropometric measurement ie, body mass index (BMI), waist circumference (WC); all patients were advised regular aerobic exercise for 30 min/d, for at least 5 d/wk and trained to achieve around 70% of his maximal heart rate. In addition, moderately energy restricted diet was advised to patients with high BMI (> 25 kg/m 2). Monthly follow up was done by measuring BMI, WC, aspartate aminotransferase, and alanine aminotransferase (ALT). Insulin resistance was calculated using homeostasis model assessment (HOMA) of insulin resistance (HOMA-IR) model, at baseline and after 6 mo. Insulin resistance was arbitrarily considered altered when it was≥ 2. Liver biopsy was done in a section of patients at baseline and after 6 mo.

RESULTS: Seventy percent (42/60) patients were overweight or obese; 95%(57/60) had central obesity (WC> 90 cm in men,> 80 cm in women). In the 45 exercise compliant patients insulin resistance decreased from 6.4±6.1 to 1.3±1.0, BMI from 26.7±3.3 kg/m 2 to 25.0±3.3 kg/m 2, WC from 95.7±8.9 cm to 90.8±7.3 cm and ALT from 84.8±43.5 U/L to 41.3±18.2 U/L (P< 0.01). In 15 exercise noncompliant patient’s insulin resistance, BMI, WC and ALT did not show significant change at 6 mo follow up. Six of 8 patients in compliant group on repeat liver biopsy showed significant change in steatosis and necroinflammation. Nonalcoholic steatohepatitis scores improved form 5.3±1.5 to 3.35±1.5. The decline in insulin resistance correlated with decline in ALT (P= 0.01, r s= 0.90) and liver histology (P= 0.03, r s= 0.73).

CONCLUSION: Life style modification improves insulin resistance resulting in improvement in ALT and liver histology in NAFLD patients.