NEW YORK (Reuters Health) - Exercise is good for mice and humans, but appears to be bad for gallstones, according to the findings of a study conducted with mice.
Dr. Kenneth R. Wilund and colleagues found that the overall gallstone weight was 2.5-fold greater in sedentary mice compared with mice that exercised. The researchers suggest that exercise may provide similar benefit to humans.
"The basic physiology of gallstone formation is pretty similar in humans and mice," Wilund told Reuters Health. Many of the proteins involved in the liver's cholesterol and bile acid metabolism are very similar, he said.
"So it is reasonable to suggest that the changes we believe were responsible for the reduction in gallstone formation in the exercise-trained mice could also occur in response to exercise training in humans," commented Wilund, of the University of Illinois, Urbana.
He and his colleagues fed 50 gallstone-susceptible mice standard chow that was supplemented to increase gallstone formation. They placed half the mice on a 12-week endurance exercise regimen that involved 45 minutes of running, 5 days a week. The remaining mice were sedentary for 12 weeks, the investigators report in the Journal of Applied Physiology.
At the end of the study period, the animals were euthanized and the gallstones were removed. The total weight of the gallstones from the sedentary mice was 143 milligrams compared with 57 milligrams for exercising mice, the investigators note.
"In most situations, gallstone formation in humans occurs over a very long period of time -- probably years," Wilund said. "As a result, it would be difficult to do a similar study in humans."
However, the process of gallstone formation is similar enough between mice and humans to infer that exercise may also limit gallstone formation in humans, he and colleagues note.
"It is well established that chronic exercise reduces the incidence of chronic diseases such as heart disease, diabetes, and certain types of cancer," Wilund continued. "This study provides preliminary evidence that perhaps we can add gallbladder disease to this list."
SOURCE: Journal of Applied Physiology, March 2008.