Physical performance and longevity in aged rats.

In humans, physical performance declines with increasing age, and in nondisabled older persons, scores on standardized performance measures, such as walking speed, repeated chair stands, and a balance test, predict the incidence of disability and reduced longevity. Here we show in aged rats (24-month-old Brown Norway x Fischer 344 male rats; n = 48) that conceptually similar performance measures, such as swimming speed and an inclined plane procedure, can be assessed longitudinally, and that over 6 months of follow-up from the age of 24 to 30 months, performance declines progressively with increasing age. High baseline performance scores predict long-term longevity, a relationship that is also found in humans. The application of standardized physical performance measures to a variety of animal models of aging may help to define similarities between species in the underlying mechanisms of the age-related decline in performance, disability, and longevity.