The human body literally glimmers. The intensity of the light emitted by the body is 1000 times lower than the sensitivity of our naked eyes. Ultraweak photon emission is known as the energy released as light through the changes in energy metabolism. The human body directly and rhythmically emits light. The diurnal changes in photon emission might be linked to changes in energy metabolism.
Bioluminescence, which is weak but visible, is sometimes produced in living organisms, such as fireflies or jellyfish, as the result of specialized enzymatic reactions that require adenosine triphosphate. However, virtually all living organisms emit extremely weak light, spontaneously without external photoexcitation. This biophoton emission is categorized in different phenomena of light emission from bioluminescence, and is believed to be a by-product of biochemical reactions in which excited molecules are produced from bioenergetic processes that involves active oxygen species. Human body is glimmering with light of intensity weaker than 1/1000 times the sensitivity of naked eyes. By using a sensitive charge-coupled-device (CCD) camera with the ability to detect light at the level of a single photon, we succeeded in imaging the spontaneous photon emission from human bodies.
The photon emission mechanism is thought to originate from the generation of free radicals in energy metabolic processes.
Excerpts from a research article by Masaki Kobayashi, Daisuke Kikuchi, Hitoshi Okamura