ABSTRACT
Introduction Regular physical activity is a major factor in preventing metabolic diseases such as maturity-onset diabetes and atherosclerotic heart disease. However, intensive exercise increases the production of free radicals, and in theory, it could augment oxidative stress, with a worsening of the individual’s long-term prognosis in terms of the metabolic syndrome, cardiac disease, cancer, Alzheimer’s disease and other chronic conditions. The immune system may also be compromised, increasing the risk of developing acute upper respiratory infections [87]. The muscle soreness that develops in the limb muscles of athletes following a period of strenuous training (particularly if eccentric exercise has been involved) is due in part to the development of microscopic lesions and an associated increase in local oxidative stress. Athletes commonly ingest nutrients with antioxidative properties in order to limit the resulting inammation and muscle soreness, and health conscious sedentary individuals may adopt a similar tactic to avert heart attacks and slow
the course of aging, although there is little evidence that such supplements are helpful if a well-balanced diet is already being eaten.
