What Maintains Energy Supply at Peak Aerobic Exercise in Trained and Untrained Older Men?

Abstract

The present study suggests that the differences between trained and untrained elderly in absolute oxygen uptake of the working muscles and peak power output at maximal exercise test are due to physical activity status. The higher aerobic capacity in the trained elderly is related to increased cardiovascular function and to a lesser extent to increased muscle mitochondria concentration and capillarity. Although untrained elderly have reduced maximal oxygen uptake at peak aerobic exercise, intrinsic regulation of mitochondrial function does not seem to be significantly altered because of aging associated physical inactivity. Therefore, untrained elderly can partially compensate for their lower cardiac output by increasing oxygen extraction to levels comparable with those of trained elderly.