Exercise Program Improves Cardiopulmonary Fitness and Reduces Waist Circumference in Postmenopausal Women With Nonalcoholic Fatty Liver Disease
Lead author Rosamar E. Fontes Rezende, MD, PhD; Claudia P. Oliveira, MD, PhD; JoAnn V. Pinkerton, MD, NCMP; and Douglas T. Dieterich, MD comment
A 24-week structured exercise training program for postmenopausal women with nonalcoholic fatty liver disease (NAFLD) significantly improved waist circumference, high-density lipoprotein cholesterol levels, and cardiopulmonary fitness, according to findings published online ahead of print in Menopause.
"Physical activity is very important in the prevention and treatment of NAFLD patients," said lead author Rosamar E. Fontes Rezende, MD, PhD, Division of Gastroenterology, School of Medicine of Ribeirão Preto, University of São Paulo. "However, adherence to physical activity protocols is difficult in this population because usually, they have more comorbidities related to insulin resistance, and more fatigue symptoms associated with inactivity and daytime sleepiness when compared with people without NAFLD."
Recent practice guidelines for the management of NAFLD demonstrate that in overweight/obese patients with NAFLD, a 7% to 10% weight loss results in improvement of liver enzymes and histology, noted senior author Claudia P. Oliveira, MD, PhD, who is from the School of Medicine at the University of São Paulo. The guidelines were released by the European Association for the Study of the Liver (EASL), the European Association for the Study of Diabetes (EASD), and the European Association for the Study of Obesity (EASO).
This present study included 40 women with NAFLD who were randomized into two groups: an exercise training group (n=19) and a control group (n=21). Most participants in both groups were obese and had diabetes, hypertension, and dyslipidemia. All participants were given a reduced-calorie, standardized diet.
The exercise program consisted of 24 weeks of a supervised exercise training program, twice a week. Training sessions were composed of a 5-minute warm up followed by 30 to 50 minutes of treadmill aerobic exercise and 5 minutes of cool down. Exercise sessions lasted between 30 and 50 minutes, with increases in exercise duration every 8 weeks.
Body composition parameters (body fat mass, body fat percentage, and skeletal muscle mass), clinical and laboratorial parameters (liver enzymes, lipids, glycemic profiles; assessment of insulin resistance; and cytokines), aerobic conditioning (a maximal cardiopulmonary test), and fat liver content were measured at baseline and at the study's end. Height, weight, body mass index (BMI), and waist circumference (WC) were also measured. Cardiopulmonary functional capacity was assessed by measuring the time to exhaustion and oxygen intake during exercise.
Significant Improvements Found in the Exercise Group
After 24 weeks, the researchers observed a significant decrease of WC (P=0.05), an increase of high-density lipoprotein cholesterol levels (P<0.05), and a trend toward a decrease in BMI (P=0.06). The following components of cardiopulmonary functional capacity also significantly improved in the exercise group compared with the control group: muscle oxygen uptake (P=0.04), time at ventilatory anaerobic threshold (P=0.01), time at respiratory compensation point (P=0.002), and time at measure oxygen consumption at peak exercise (P=0.007).
No significant changes in insulin resistance were found, and a small but nonsignificant decrease in the rate of evolution of steatosis was found in the exercise group. The degree of steatosis generally increased in the control group during the study.
Between-group analysis showed that physical activity had no significant effect on body composition or glycemic profile. In addition, liver enzymes and cytokine serum levels did not change significantly between the groups.
"This study shows the benefit of counseling women at risk of diagnosis with fatty liver disease about the benefits of increased physical activity, including less fat around the middle, improvement in good cholesterol, and improved ability to exercise (cardiopulmonary functional capacity)" commented JoAnn V. Pinkerton, MD, NCMP, Executive Director of the North American Menopause Society. "Longer studies with more women are needed to show whether exercise decreases the extent of fat in the liver, prevents liver cirrhosis, or decreases the inflammatory reactions seen with this disease."
"Postmenopausal woman with NAFLD should be undertaken at least 150 minutes/week of moderate intensity aerobic exercise," Dr. Rezende said. "Resistance training also is effective and promotes musculoskeletal fitness, with effects on metabolic risk factors."
"The diet of patients with NAFLD should have low carbohydrate and fructose content, but should avoid extreme restriction of carbohydrates," Dr. Oliveira said. "Healthy lifestyle and control of metabolic risk factors should be recommended for all patients with NAFLD."
Without Structure, Most Patients Fail To Change Diet and Exercise
"Two of the things that are most important in treating fatty liver disease are diet and exercise," commented Douglas T. Dieterich, MD, Director of the Institute of Liver Medicine at the Mount Sinai Health System in New York, NY. "However, without structure most patients fail to implement either of these programs."
"Clearly, the structured exercise program was successful in reducing WC, increasing HDL and increasing cardiovascular endurance," Dr. Dieterich said. "To get these benefits, just joining a gym is not good enough—patients should work with a trainer or take 3 to 4 structured classes per week to ensure adherence and optimally increase cardiopulmonary fitness. The effect of this is really important because the leading cause of death in people with fatty liver disease is cardiovascular disease, so if structured exercise programs increased cardiovascular health, then that's the best way to prevent long-term consequences."
"Structured exercise is clearly a huge benefit here and there are many ways to do it," Dr. Dieterich noted. "People can join walking clubs, go to aerobic classes, spin classes, hire a personal trainer, but they need to have some peer pressure I think to be successful in continuing the exercise regimen."
"I think the main point is that the major risk for mortality and people with fatty liver is cardiovascular death and that structured exercise programs reduce WC, increase HDL good cholesterol, and increase cardiovascular fitness—all which would logically lead to a decrease in cardiovascular mortality," Dr. Dieterich concluded.
July 12, 2016