Exercise intensity and antioxidant ability.

We performed maximal exercise tests on 6 men using a bicycle ergometer and then measured the ferric-reducing ability in plasma to clarify the relationship between antioxidant status and exercise intensity. The ferric-reducing ability showed a rectilinear increase with the increase in exercise intensity, whereas the generation of hydroxyl radicals showed a decrease with the increase in exercise intensity. Also, the generation of hydroxyl radicals showed a symmetrical correlation to lactate level in plasma. These results suggest that antioxidant ability is enhanced with an increase in exercise intensity, and that the lactate level, which increases with physical exercise, may act as a scavenger of free radicals.