Sprinting or other intense exercise can help young adults with type 1 diabetes normalize their muscle metabolism. In a new study, a group with diabetes and another without diabetes (overall average age 25) underwent 7 weeks of sprint training. After the training, the people with type 1 were shown to have improved their muscular capacity, bringing it more in line with the other group. The authors also note that the rigorous training had no ill effects, particularly because participants were closely monitoring themselves for hypoglycemia.
Source: Diabetes Care, November 2008