LONDON: Regular high-intensity interval training (HIIT) exercises such as squats, sprints, and pedalling can improve the treatment of non-alcoholic fatty liver disease by impacting on several metabolic pathways in the body, finds a new study.
A team from the University of Eastern Finland found that regular HIIT exercise over a period of 12 weeks significantly decreased the study participants' fasting glucose and waist circumference, and improved their maximum oxygen consumption rate and maximum achieved workload.
These positive effects were associated with alterations in the abundance of a number of metabolites. In particular, exercise altered amino acid metabolism in adipose tissue, according to the study published in Scientific Reports.
Non-alcoholic fatty liver disease (NAFLD) is the most common liver disease, affecting approximately 25 per cent of the world's population. Being largely asymptomatic, the disease may progress from the accumulation of fat in liver cells to liver inflammation and liver cirrhosis.
NAFLD is associated with obesity and other characteristics of the metabolic syndrome, such as Type 2 diabetes and abnormal blood lipid concentrations. The accumulation of fat in the liver can be reduced by weight loss and a health-promoting diet.
Exercise is an integral part of the treatment of NAFLD. The benefits of exercise may relate not only to weight management, but also to alterations in the metabolites produced by the body and gut microbes, whose role in fatty liver disease remains poorly understood.
The study involved 46 subjects diagnosed with NAFLD, who were divided into an exercise intervention group that had a HIIT session twice a week, plus an independent training session once a week for 12 weeks, and into a control group that did not increase exercise during the study.
The most significant alterations were observed in amino acids and their derivatives, lipids, and bile acids.
The levels of various gut microbial metabolites were also altered as a result of exercise, which is suggestive of changes in the composition of gut microbes, or in their function.
Among these metabolites, an increased amount of indolelactic acid, for example, can strengthen the intestinal mucosa, immune defence, and glucose balance.
Based on the findings, exercise can have a beneficial effect on many factors contributing to disease in patients with NAFLD, even without weight loss and dietary changes, the researchers said. Adipose tissue seems to play a key role in these effects.