Independent effects of physical activity in patients with nonalcoholic fatty liver disease

Abstract

Nonalcoholic fatty liver disease, characterized by elevated liver enzymes, central obesity, and insulin resistance, is becoming increasingly prevalent. The effects of changes in physical activity on the metabolic profile of this group have not been reported. We assessed at 3 months the impact of a behavior change-based lifestyle intervention on physical activity and the effects of this change on the metabolic profile of people with fatty liver disease. In all, 141 participants with nonalcoholic fatty liver disease were prospectively enrolled into either a low-or moderate-intensity lifestyle intervention or to a control group. Physical activity was assessed using a validated reporting tool and physical fitness was measured using the YMCA protocol on a cycle ergometer. Individualized counseling to increase physical activity was provided. Overall, 96% of participants attended the 3-month follow-up assessment. Participants in the moderate-and low-intensity intervention groups were 9 times more likely to increase physical activity by an hour or more per week compared to controls. Patients increasing or maintaining their reported physical activity to >150 minutes/week, and those who increased their objective levels of fitness, had the greatest improvements in liver enzymes and other metabolic indices compared to those who were least active. This effect was independent of weight loss and was corroborated by an objective measure of fitness. There was no dose-response effect on liver enzymes with incremental increases in physical activity above 60 minutes/week. Conclusion: Lifestyle counseling interventions are effective in improving physical activity behavior. Maintaining or increasing physical activity provides health benefits for patients with fatty liver, independent of changes in weight. (HEPATOLOGY 2009;50:68-76.)

Moderate to vigorous physical activity volume is an important factor for managing nonalcoholic fatty liver disease: A retrospective study

“…2B). Several studies have reported indications for obtaining the direct effect of exercise on hepatic steatosis [6][7][8] ; exercise with less frequency and dose was found to be effective in both light and moderate volume exercise programs, 34 the PA volume of which was below the current guidelines for health promotion 35 and for managing body weight. 36 At present, scientific evidence for the benefits of PA and the optimal dose and modality for PA in NAFLD management is limited.…”

“…3 With respect to physical activity (PA), recent reports on clinical outcomes have indicated that physical inactivity and low aerobic fitness are underlying reasons for the increased number of NAFLD cases, 4,5 and that both aerobic and resistance exercises have specific effects on NAFLD treatment in the absence of weight reduction. [6][7][8] We have recently proven the therapeutic effects of increased PA with or without dietary restriction in greatly reducing hepatic inflammation and the related oxidative stress levels outweigh those achieved by dietary restriction alone. 9,10 Thus, although there is an overall paucity of evidence on the benefits of PA as a treatment for NAFLD, management should include assessing PA levels and setting of lifestyle goals based on adopting regular exercise, with a focus on attaining sustainable PA habits.…”

Fitness versus fatness: Moving beyond weight loss in nonalcoholic fatty liver disease

“…1 Concomitant with pharmacotherapy trials, there is increased interest in the efficacy of lifestyle interventions to reduce liver fat and steatohepatitis. [2][3][4][5] In this context, weight reduction and behavior therapy-based interventions have been reviewed in HEPATOLOGY, 6 but there is little information on the role and importance of physical activity in NAFLD.…”

Physical training at sub-threshold intensity reduces the prevalence of hepatic steatosis after high-fat diet in rats

“…Although studies that have observed the efficacy in the treatment of NAFLD in human beings observed the concomitant reduction of 3 to 10% in body weight (Johnson et al, 2012), there is evidence that physical training is able to reduce the hepatic lipid levels by mechanisms independent of weight variation (George et al, 2009), once calorie readjustment after induced obesity did not appear to present benefits in the metabolic parameters, associated with insulin resistance, when physical training was not included (Estadella et al, 2004).…”