Resistance training in the gym leads to a fall in liver fat levels. This is the finding of a new study held at the University in cooperation with Tel Aviv Medical Center and Tel Aviv University. “For patients suffering from physical limitations or low motivation that prevents them performing aerobic exercises, resistance training can be an effective alternative,” comments Dr. Shira Zelber-Sagi from the School of Public Health, who undertook the study.

On the basis of past studies, fatty liver disease is defined as a fat rate in excess of 5-10 percent of liver volume. The disease affects approximately 30 percent of the public and is considered the commonest liver disease in the Western world. Excessive weight, abdominal obesity, diabetes, dyslipidemia, and in particular triglycerides increase the risk of developing fatty liver disease, which can lead to inflammation and cirrhosis of the liver.

The disease is usually asymptomatic, although patients sometimes report fatigue and a lack of vitality by comparison to healthy individuals. Prof Oren Shibolet adds that "Fatty liver causes morbidity and mortality due to metabolic complications such as diabetes and cardiovascular disease, the development of cirrhosis and liver cancer. Because drug treatment for the disease is very limited or nonexistent, the main emphasis is on life style modifications. In this aspect our study is one of a few clinical trials to show the benefit of resistance training in reducing liver fat".

According to Dr. Zelber-Sagi, although patients with the disease recognize the importance of physical activity, they often lack the motivation to engage in such activity, particularly in the case of aerobic exercises, which are usually time consuming.

The current study was undertaken by a team of researchers from the University and the Tel Aviv Medical Center led by Dr. Shira Zelber-Sagi, Prof. Oren Shibolet, and Assaf Buch. The researchers decided to examine the impact of resistance training – which is usually briefer and more focused than aerobic exercises – on fatty liver disease. The study included 82 subjects aged 20-65 who were diagnosed by means of an ultrasound as suffering from fatty liver disease over the six months before the beginning of the study. The participants were divided randomly into a resistance training group and a control group that was asked only to undertake stretching exercises. The participants were asked not to change their physical activity habits during the study, to continue their usual diet, and to take their prescribed medicines. During the study the participants underwent examinations of weight, blood pressure, a blood test for liver enzymes, lipids, blood sugar, and insulin. Resistance training in the gym was defined according to a uniform protocol, with the level of resistance adjusted to the patient’s capabilities. The training, that was desighned and delivered by Assaf Buch, included several sets of different resistance exercises involving the arms, chest, and legs and lasting for a total of 40 minutes, three times a week.

At the end of the three-month study, the researchers found that resistance training in the gym led to a decrease in liver fat based on the fat content of the liver as detected in the special ultrasound examination employed by the study. Developed by Dr. Muriel Webb, this examination enables the quantification of liver fat. Dr. Zelber-Sagi explains: “The resistance training was not intended to reduce body weight significantly, and indeed overall weight loss was very slight. However, it seems that the resistance training had a specific impact in terms of a fall in liver fat levels as measured in the ultrasound examination.”

The study also found that gym training led to a significant fall in blood cholesterol levels. “We assume that the physical exercise improves the resistance to insulin, thereby reducing the production of cholesterol in the liver and its level in the blood,” the researchers commented. This study also shows for the first time that resistance training led to a reduction in ferritin levels in the blood. Ferritin is a protein found in the liver that facilitates the storage of iron. However, elevated levels of ferritin can be indicative of liver damage, including inflammation. Accordingly, a fall in ferritin levels may reflect an improvement in the condition of the liver

"We strongly recommend patients with fatty liver to get involved in routine physical activity, be it resistance training or aerobics, maintain a healthy diet and reduce weight", Prof Shibolet concludes.

Dr. Zilber-Sagi concludes “We know how hard it is for people to lose weight and to stick to weight reduction diets. Accordingly, it is important to find additional ways we can treat patients on a long-term basis while enabling them to maintain a high quality of life. Anaerobic training is one of these ways.”