Hormesis occurs when a metabolic stressor stimulates the cells to improve overall health. This is similar to the way exercise works.
Exercise is considered a stress on the body that causes a temporary increase in reactive oxygen species (free radicals), initiating a response to the stress that over time improves oxygen and blood delivery to the muscles as well as improve strength of the mitochondria.
Red Light also serves as a low-level stress to the cells. The end result of light stimulation includes producing healthier cells that can produce more energy, have stronger anti-oxidant and anti-inflammatory responses and are more resilient to stress.