Insulin resistance and nonalcoholic fatty liver disease (NAFLD):
Sixty patients (75% male, mean age 40.0) with nonalcoholic fatty liver disease (NAFLD) participated in a study looking at the link between regular aerobic exercise and insulin resistance, aminotransferase level (high levels signal liver damage or disease) and liver histology after 6 months. All patients were advised to exercise regularly for 30 min/d at least 5 days per week and trained to achieve around 70% of maximal heart rate. In 45 exercise compliant patients insulin resistance decreased from 6.4 to 1.3, body mass index (BMI) from 26.7 kg/m(2) to 25.0 kg/m^2, waist circumference (WC) from 95.7 cm to 90.8 cm and alanine aminotransferase (ALT) from 84.8 U/L to 41.3 U/L (P < 0.01). No significant change in insulin resistance, BMI, WC and ALT were report at 6-month follow-up in the 15 noncompliant participants. Six of 8 patients in compliant group on repeat liver biopsy showed significant change in steatosis (abnormal retention of lipids within a cell) and necroinflammation. Nonalcoholic steatohepatitis scores improved form 5.3 to 3.35. This study showed that regular aerobic exercise by promoting weight loss resulted in improvement in insulin resistance, aminotransferase level and liver histology after 6 mo. (15)