Are there any health benefits associated with reactive oxygen species?

Yes, moderate levels of ROS can produce several health benefits. This process is known as hormesis, which is the concept that suggests exposure to mild stressors like ROS can stimulate adaptive responses which enhance overall human health. For example, ROS can induce oxidative stress and damage to cancer cells. Regulated levels of ROS can trigger apoptosis in malignant cells and thus inhibit tumor growth. Radiation therapy in cancer patients functions by inducing ROS-mediated damage to malignant cells. Another example is during physical exercise, which stimulates ROS production in skeletal muscles. Moderate levels of ROS generated from exercise activates signaling pathways that promote muscle adaptation. When there is a regulated level of extracellular ROS, ROS is produced by immune cells to neutralize pathogens. Normal intracellular ROS levels assist in cellular signaling and regulation of gene expression. Thus, when there are maintained levels of ROS, the body works to naturally benefit from the effects of ROS by providing an immune response and assisting in different cellular processes.