Mouse study: When it comes to living longer, it's better to go hungry than go running

BETHESDA, Md. (May 14, 2008)— A study investigating aging in mice has found that hormonal changes that occur when mice eat significantly less may help explain an already established phenomenon: a low calorie diet can extend the lifespan of rodents, a benefit that even regular exercise does not achieve.

“We know that being lean rather than obese is protective from many diseases, but key rodent studies tell us that being lean from eating less, as opposed to exercising more, has greater benefit for living longer. This study was designed to understand better why that is,” said Derek M. Huffman, the study’s lead author.

The study applies only to rodents, which are different in some key ways from humans, cautions Huffman. However, at least two studies which examined people who engage in high-volume exercise versus people who restricted their calorie intake, had a similar outcome: caloric restriction has physiological benefits that exercise alone does not. Researchers expect that clues to the physiology of longevity in mice will eventually be applied to people, Huffman said.

The study, “Effect of exercise and calorie restriction on biomarkers of aging in mice,” appears in the May issue of the American Journal of Physiology published by The American Physiological Society (APS; www.The-APS.org). The study was carried out by Huffman, Douglas R. Moellering, William E. Grizzle, Cecil R. Stockard, Maria S. Johnson and Tim R. Nagy, all of the University of Alabama-Birmingham (UAB) and funded by the UAB Center for Aging. Dr. Huffman is now at the Albert Einstein College of Medicine in New York.

The study built upon previous studies that showed:

• Rats that exercise regularly will, on average, live longer compared to a group that eats the same amount but does not exercise. This is because exercise prevents some diseases, which allows more individual animals to live out their expected life span.