Physical exercise and free radical

Objective: Exercise can promote health, but the exercise with improper pattern and intensity is bad for health and one of the reasons is probably that exercise can produce free radical. This article reviews and summarizes the literatures from three aspects: the changing regularities of oxidation and anti-oxidation system in vivo after an acute aerobic exercise, a high intensity anaerobic exercise and the different intensity exercises, so as to find the best intensity of physical exercise from the point of free radical. Data sources: Relevant articles at home and abroad published from January 1978 to December 2003 were searched on www.ncbi.nlm.nih.gov/PubMed and www.ncki.net by using the keywords of "free radical, exercise, intensity", and the articles were checked one by one. Study selection: Totally 100 articles the relation between exercise and free radical were selected. The literatures of non-randomized study were excluded, and those of non-blinded study were not excluded. Data extraction: Among the 100 articles, 24 were deleted for they were repeated to different degree, and the rest 76 were classified and sorted for review, and 36 of them served as references. Data synthesis: Most articles studied the changes of free radical after an acute exercise and no articles were found to study its changes during exercise. Besides, there was deficiency of study on the relationship between continuous and incremental intensity exercise and free radical. Conclusion: It is suggested from the point of free radical that the intensity, which unbalances the oxidation and anti-oxidation systems in vivo, should be the proper intensity for health during exercise.