While it is not advisable to expose yourself to blue light of our computer or smartphone screens in the evening, it is because it has been shown that it delays the secretion of melatonin, sleep hormone. It would also harm the retina. But that’s not all: according to a new Japanese scientific study, published on June 11, 2021 in the journal Scientific Reports, the blue light would also modify the body metabolism during sleep.
Researchers at the University of Tsukuba (Japan) compared the effects of light emitting diodes (LEDs), widely adopted for their economic properties, with organic light emitting diodes (OLED) about the physical processes that occur during sleep.
Polychromatic white LEDs emit a large amount of blue light, which has been associated with many negative health effects, while OLEDs emit polychromatic white light which contains less blue light.
The researchers exposed 10 men to LEDs, OLEDs or dim light for 4 hours before sleeping. The scientists then measured energy expenditure, core body temperature, fat oxidation, and 6-sulfatoxymelatonin – which is a measure of melatonin levels – during sleep.
Verdict: “Although no effect on sleep architecture was observed, energy expenditure and core body temperature during sleep were significantly reduced after exposure to OLED. Furthermore, fat oxidation during sleep was significantly lower after exposure to LED compared to OLED”, Detailed Professor Tokyuama, who led the study, in a communicated.
“Thus, exposure to light at night is linked to fat oxidation and body temperature during sleep. Our results suggest that specific types of light exposure can influence weight gain, as well as other physiological changes”, Concluded Professor Tokuyama.
The authors hope that their work will contribute to a better selection of light sources, in particular to improve the health of night workers.