The Role of Exercise-Induced Reactive Oxygen Species (ROS) Hormesis in Aging: Friend or Foe.

Reactive oxygen species (ROS) are oxygen derivatives that arise intrinsically from the oxidative phosphorylation process and extrinsically as a response to xenobiotics and pollution. ROS is involved in various conditions such as exercise, aging, inflammation, and neurodegenerative diseases. In the aging process, increased cellular senescence and decreased endogenous antioxidants also occur.