Vitamin E and the oxidative stress of exercise.

There is clear evidence that contracting skeletal muscle generates a complex set of reactive oxygen and nitrogen species and that the pattern and magnitude of this generation is influenced by the type and frequency of the muscle contraction protocol. The functions of these species in exercising organisms are still unclear although data have been presented indicating that they play a role in contraction-induced muscle damage and/or in signaling adaptive responses to contractions. Vitamin E has been claimed to exert a regulatory effect on the actions of contraction-induced oxidants for a considerable time, although evidence for any specific role in this area is lacking. A review of studies in this area suggests that vitamin E supplements are unlikely to reliably reduce the severity of contraction-induced muscle damage but, in contrast, appear capable of modulating redox-regulated adaptive responses to contractions. Full evaluation of the roles of oxidants and antioxidants such as vitamin E in responses of muscle to contractions should enable the manipulation of these processes with potential beneficial effects on maintenance of optimal muscle function.