According to a study conducted by the University of South Carolina in Columbia, active men are less likely to develop a duodenal ulcer (ulcers that occur in the upper part of the small intestine) than those who are idle. The results, reported in the August 2000 issue of the Western Journal of Medicine, showed that in more than 11,000 subjects tested those who either walked or ran a distance of 10 miles a week had 1/2 to 1/3 the risk of developing an ulcer over 20 years. While the connection is unclear, exercise may decrease the stress associated with ulcers and/or enhance the immune system.