LIPOIC ACID SUPPLEMENTATION IN PHYSICAL EXERCISE

Abstract

Depending on the intensity and duration, physical exercise causes varying extent of oxidant insult to tissues and organs. Given that oxidants are not only triggers of damage but may also serve as signaling messengers, the physiological significance of exercise-induced oxidant challenge can be expected to have both negative (acute damage) as well as positive (adaptation) aspects (I). α-Lipoic acid (LA) is a natural thiol antioxidant commonly used as a dietary supplement. We examined the effect of intragastric LA (150 mg/kg, 8 weeks) and endurance training on tissue LA, glutathione metabolism, and heat shock responses at rest and following exhaustive treadmill exercise in 9 wk old Wistar rats. LA supplementation increased the level of LA in the red gastrocnemius muscle, and total glutathione content in the liver and blood, but did not affect heat shock protein (HSP70) levels or heat shock factor activation. Exercise-induced decrease in heart glutathione S-transferase activity was prevented by LA supplementation. Eight weeks endurance training remarkably increased HSP70 levels in all the tissues examined. This study supports that endurance training up-regulates cellular defenses and that orally supplemented LA may provide additional protection against oxidative challenge at rest and in response to exercise. I. Sen et al (Eds.). Handbook of oxidants and antioxidants in exercise. Elsevier Science Publishers, Amsterdam, ISBN 0-444-81765-4, pp 1207, 2000.