The human body emits a visible light in very small quantities at levels that increase and decrease with the day, researchers have found.
Previous studies have shown that our body emits visible light, 1,000 times less intense than the levels to which our naked eyes are sensitive. And such a phenomenon is not just restricted to humans, virtually all living creatures emit very weak light, which is thought to be a by-product of biochemical reactions involving free radicals.
In order to know more about this faint visible light, researchers in Japan used extraordinarily sensitive cameras which were capable of detecting single photons, reports Fox News.
To reach the conclusion, five healthy, young male volunteers were placed bare-chested in front of the cameras in complete darkness in light-tight rooms. The time duration of the whole process was: 20 minutes every three hours from 10 a.m. to 10 p.m. for three days.
After analyses, boffins found that the body glow rose and fell over the day, with its lowest point at 10 a.m. and its peak at 4 p.m., dropping gradually after that.
The findings suggest there is light emission linked to our body clocks, most likely due to how our metabolic rhythms fluctuate over the course of the day. Also, researchers found, that faces glowed more than the rest of the body. The explanation for this maybe that faces are more tanned than the rest of the body, since they get more exposure to sunlight.
Researcher Hitoshi Okamura, a circadian biologist at Kyoto University in Japan said that the finding suggests cameras that can spot the weak emissions could help spot medical conditions.
"If you can see the glimmer from the body's surface, you could see the whole body condition," said researcher Masaki Kobayashi, a biomedical photonics specialist at the Tohoku Institute of Technology in Sendai, Japan.
The scientists detailed their findings online July 16 in the journal PLoS ONE.