EXERCISE AND BRAIN FUNCTION: IS IT REDOX REGULATED?

Regular exercise has systemic beneficial effects including the promotion of brain function. The adaptive response to regular exercise includes the up-regulation of the enzymatic antioxidant system, and modulation of oxidative damage. Reactive oxygen species (ROS) are important regulators of cell signaling and exercise through activity dependent modulation of metabolism and/or direct activation of ROS generating enzymes, thus, modulating the cellular redox state in the brain. ROS are also involved in the self-renewal and differentiation of neuronal stem cells and, as a result, exercise-mediated neurogenesis could be associated with ROS production. Exercise has a powerful effect on the immune system, and readily alters the production of cytokines. Certain cytokines, especially IL-6, IL-1, TNF-a, IL-18 and interferon gamma are actively involved in the modulation of synaptic plasticity and neurogenesis. Cytokines can also contribute to ROS production. ROS- mediated alteration of lipids, protein and DNA could directly affect brain function while exercise modulates the accumulation of oxidative damage. Oxidative alteration of macromolecules, to a moderate degree, can activate signaling processes. Hence, it could be part of the adaptive response to exercise training.