Rats ‘Born to Run’ Show How Fitness Extends Life:
Britton and colleagues bred rats for 11 generations to be good or poor runners.Then they tested their ability to exercise, without training them first, so that differences could not be attributed to practice.
Their high-capacity runners can exercise on a little rodent treadmill for 42 minutes on average before becoming exhausted, while the low-capacity runners average only 14 minutes. It is a 347 percent difference in capacity, they report in Friday’s issue of the journal Science.
Selective breeding had quite an effect on performance — and health:
“We found that rats with low aerobic capacity scored higher on risk factors linked to cardiovascular disease — including high blood pressure and vascular dysfunction,” said Ulrik Wisloff, a professor of exercise physiology at the Norwegian University of Science and Technology in Trondheim.
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“Rats with low aerobic capacity also had higher levels of blood fat disorders (such as high cholesterol), insulin resistance (a pre-diabetic condition) and more abdominal fat than high-capacity rats,” added Sonia Najjar, of the Medical College of Ohio in Toledo.