Science has long known that regular physical exercise decreases the risk for diabetes. In some people, however, that's not the case.
Researchers and clinicians from the German Center for Diabetic Research between the Helmholtz Zentrum München and the University Hospital Tübingen may have discovered why some patients don't respond to exercise.
Training intervention studies--in which study participants complete a well-defined intensive exercise program--consistently showed that about one in five participants don't develop positive metabolic changes. These patients, called “non-responders,” can exercise intensively without showing positive changes in insulin resistance.
Insulin is the hormone that regulates blood sugar and insulin resistance is one of the early signs of diabetes.
Cora Weigert, PhD, of the University Hospital Tübingen led the researchers. Dr. Weigert is a professor and department head at the Institute of Diabetes Research and Metabolic Diseases (IDM), a research unit of the Helmholtz Zentrum München at the University of Tübingen.
Dr. Weigert and team studied 20 middle-aged subjects who completed an eight-week endurance training program. The study participants were at high risk of diabetes and had not previously been physically active.
The researchers examined skeletal muscle changes at the molecular level in all study participants.
Non-responders showed less improvement in insulin sensitivity. Analysis of their skeletal muscles indicated a chemical messenger called TGF-beta was activated after training. Further research indicated TGF-beta interferes with genes whose function is to burn sugar and fat.
"At the moment we are still trying to understand what causes TGF-beta to be activated in the muscle of some participants. There is some evidence that a different training program where the intensity or length of training is adapted to an individual's ability to respond to physical exercise would be successful, and would help to prevent diabetes," Dr. Weigert said in a press release. "I am convinced that everyone-–given a suitable training program-–can lower their personal diabetes risk."
The study was published in the June issue of Diabetes.
Information on study funding and conflict of interest was not available.