The collagen biomarker of aging can be influenced by physical exercise also in senescent rats

The normal processes of aging lead gradually to impairment of the function of most organs and to a gradually increasing force of mortality. This can to some extent be counteracted by life-long physical exercise as evidenced by epidemiological studies. The same is seen in animal experiments, where the mean survival time but not the maximum lifespan is increased by life-long physical exercise. In previous studies we have shown that the with aging increasing thermal stability of collagen-a biomarker of aging-is slowed down by life-long physical exercise in male Sprague-Dawley rats. Here we investigate whether late onset physical exercise also has a beneficial effect on this biomarker of aging. We found that mild exercise (100m/day in a treadmill) retards the increase of thermal stability of collagen, when the rats are trained from 27 to 30 months of age. On the other hand more extensive exercise (400m/day from 24 to 27 and 200m/day from 27 to 30 months of age) has the opposite effect, which is in agreement with our previous study on rats trained from 12 to 24 months of age. We conclude that senescent rats can also benefit from physical exercise and that the optimum amount of training decreases with age.