The Association between Physical Exercise and Reactive Oxygen Species (ROS) Production

Abstract

The importance of exercise has been widely accepted by the public, professional organizations and the medical community, and the number of people around the world who practice day-to-day regular physical activity has recently increased. Physical activity is a primary requirement for the maintenance and promotion of health. However, intense exercise induces an increase in substrate utilization by the working muscles, resulting in an increased use of oxygen. This rise in oxygen consumption combined with the activation of specific metabolic pathways during or after exercise results in the generation of Reactive Oxygen Species (ROS). These substances are produced naturally by oxidative metabolic processes and are highly reactive. ROS can be useful in some situations; for example, macrophages use hydrogen peroxide to destroy bacteria. ROS increases during high-intensity exercise and its production is related to a large number of diseases, such as emphysema, inflammatory diseases, atherosclerosis, cancer and aging. During evolution, living organs developed an endogenous mechanism to minimize the damage caused by ROS, termed the antioxidant defense system. The imbalance between the production of ROS and the removal of these compounds by the antioxidant defense system causes a condition known as oxidative stress. This interesting paradox is exemplified by the hypothesis that physical exercises known to promote appropriate standards of health are also related to increased ROS production, which in turn closely correlate with various diseases. Recent publications have shown that ROS produced by exercise in adequate amounts may be linked to exercise benefits, both for health and for athletic performance. Thus, the aim of this article is to examine the close association between physical exercise and the production of ROS through an extensive literature review.