Effects of free radicals and antioxidants on exercise performance

Free radicals are very reactive chemical species that can cause oxidation injury to the living beings by attacking the macromolecules like lipids, carbohydrates, proteins and nucleic acids. Antioxidants protect cells from damage caused by unstable molecules known as free radicals. The scope of this review was to critically examine the effect of free radicals and antioxidants on exercise and techniques for positive homeostasis between the two for better exercise performance. Our bodies naturally protect themselves against free radicals with a class of substances called antioxidants. Excess free radical formation has been hypothesized to contribute to cancer, atherosclerosis, aging and exercise associated muscle damage. Regular low to moderate physical exercise enhances the antioxidant defense system and protects against exercise induced free radical damage. Heavy exercise increases the level of free radicals. Free radical production or loss of antioxidant protection can adversely affect performance. Antioxidant supplements such as vitamin C, E and beta-carotene and recently N-acetylcysteine (NAC) have been touted as beneficial for enhancing exercise performance. However, experimental studies seem not to fully support this notion except NAC. It was concluded that people involved in acute or chronic physical exercise programs should avoid overtraining and if they must be engaged in high intensity training, they may benefit from some of the antioxidant supplementation such as NAC. It was recommended that antioxidant food supplements in moderate doses (recommended daily allowance) for both athletes and non-athletes could be encouraged; also that training grounds should be located outside industrialized cities to avoid unnecessary over-production of free radicals.