AGING, FAT OXIDATION AND EXERCISE

Aging is characterized by deleterious changes in body composition and in fat distribution. The mechanisms that determine the aging-associate d changes in body composition are not well defined, but the evidence s uggests that the loss of fat-free mass is at (east partially attributa ble to physical inactivity. The increase in fat mass may be the result of alterations in fatty acid metabolism. Indeed, fat oxidation is dec reased in elderly individuals in several physiological conditions: a) at rest, b) during exercise, and cl in response to meal ingestion (aft er weight loss). These defects are related in part to loss of fat-free mass, but may also be the consequence of estrogen loss (in women) and /or a decrease in the intrinsic capacity of muscle for fat oxidation, and are amenable to partial correction by exercise training. Special e mphasis should be placed in future studies upon the role of steroid ho rmone in the regulation of fatty acid metabolism in elderly individual s (especially women), as well as therapeutic interventions that may in crease the quantity of fat-free mass and/or fat oxidation. (C) 1997, E ditrice Kurtis.