EXERCISE AND FREE RADICAL IN ELDERLY / 体力科学

ABSTRACT

Oxidation produces free radicals, which cause peroxidation, enzyme inhibition and genetic damage in muscle cells. Genetic damage to cells and tissues caused by free radicals facilitates aging. Therefore, the functional capacity of the antioxidant system against free radicals is important to protect cells and tissues. The health benefits of regular exercise are well documented in a large number of reports. Moderate exercise can result in greater health benefits than vigorous exercise, because intense activity may generate free radicals. This is evidenced by an increase in effects such as lipid peroxidation, glutathione oxidation, and oxidative protein damage. These are regarded as an indirect sign of muscle cell damage. During exercise, increased aerobic metabolism is a potential source of free radicals (oxidative stress) in mitochondria. In muscle cells, mitochondria are one important source of reactive intermediates that include superoxides, hydrogen peroxide, and possibly hydroxyl radicals. Unfortunately, because research focusing on oxidative stress and antioxidants following exercise has up to now been narrow in scope, the mechanism linking oxidative stress and antioxidants in muscle tissue during exercise, is not fully understood. Knowledge of the mechanism of free radical formation during exercise will be useful and may lead to the prevention of oxidative stress and damage associated with physical activity. Although the capability of an antioxidant system can be estimated by measuring the content or activity of cellular superoxide dismutase isozymes, catalase and glutathione peroxidase, scavenger capacity against free radicals in muscle cells has not been investigated. Recent progress in electronics has made it possible, using electron spin resonance and a spin-trapping technique, to determine and quantify the reactive oxygen species involved in chemical reactions. Biological applications of electron spin resonance include detecting the production of free radicals and radical scavenging activity in living specimens. This review paper provides a brief account of how exercise leads to oxidative stress and the link with antioxidants, and suggests future paths of research.