The rats in the study, by scientists from the Norwegian University of Science and Technology, the Medical College of Ohio, Williams College and the U-M Medical School, are the product of eleven generations of artificial selection for exercise capacity conducted by U-M scientists Steven Britton, Ph.D., and Lauren Gerard Koch, Ph.D.
Although they are all descended from the same founder population of genetically mixed lab rats, the experimental rats differ in their ability to use oxygen efficiently and generate the energy it takes to run for long periods. For example, the high-capacity runners in generation 11 can exercise continuously on a treadmill for 42 minutes on average before exhaustion forces them to stop, while the low-capacity runners average only 14 minutes.
The most clinically useful finding reported in the paper was the close association in the experimental rats between low aerobic exercise capacity and high scores for risk factors linked to metabolic syndrome - physical changes often seen in people who later develop cardiovascular disease and diabetes.
Britton and Koch hope their rats will help scientists evaluate new therapeutic drugs for cardiovascular disease and diabetes, or develop diagnostic tests to identify people most likely to develop these diseases as they get older.
"The reality of having a genetic determinant of our existence is that there are some people who are born with less ability to take up oxygen and transfer energy than others," Britton says. "These people may have to work harder and will never reach the level of a professional athlete, but almost everyone can improve their aerobic capacity and health status with regular exercise."
MEDICA.de; Source: University of Michigan Health System