WEDNESDAY, April 13 (HealthDay News) -- Aerobic exercise may slow the progression of non-alcoholic fatty liver disease in obese people, finds a new study.

This type of workout appears to benefit these patients by increasing their metabolism and easing the oxidative damage caused by the liver disease, said the Cleveland Clinic researchers.

Their study included 15 obese people with non-alcoholic fatty liver disease who walked on a treadmill at 85 percent of their maximum heart rate for one hour a day for seven consecutive days. The exercise increased the participants' insulin sensitivity and improved the liver's polyunsaturated lipid index (PUI)-- believed to be a marker of liver health -- by 84 percent.

These improvements were linked to an increase in the hormone adiponectin, which plays a role in the body's response to insulin and has anti-inflammatory properties that help reduce the risk of heart attack, the researchers said. Low levels of adiponectin are common in obese people.

The study is slated to be presented this week at the American Physiological Society's Experimental Biology meeting in Washington, D.C.

"We were able to correlate changes in adiponectin with PUI and the body's resting energy metabolism," Jacob M. Haus, a research fellow in the pathobiology department at Cleveland Clinic's Lerner Research Institute, said in an APS news release. "The latter gives us an indication of whether carbohydrate or fat is being metabolized. After exercise, the participants were burning more fat."

Non-alcoholic fatty liver disease, which affects 2 to 5 percent of Americans, is excess fat and inflammation in the liver. When severe, it can lead to cirrhosis, liver failure or liver cancer, according to the National Digestive Diseases Information Clearinghouse.

"We like to think of exercise as medicine," he added.

Burning fat can help protect against oxidative damage and therefore the damage of fatty liver disease, he explained.

Because the study is small and being presented at a medical meeting, the findings should be considered preliminary until they are published in a peer-reviewed journal and confirmed in larger studies.

More information

The American Liver Foundation has more about non-alcoholic fatty liver disease.