The researchers found that longer exposure to blue light was associated with earlier onset of puberty in female rats, which included decreased levels of melatonin, increased levels of certain reproductive hormones, and physical changes in their ovaries.

Sorry for the blue light

The use of mobile devices that emit blue light has previously been associated with sleep disruption in children, but these findings point to additional risks for child development and future fertility.

Since blue light prevents the increase in the evening increase of the hormone melatonin, which prepares our body for rest and sleep, sleep quality deteriorates in both children and adults due to the deterioration of our biological clock. Melatonin levels are generally higher before puberty than during puberty, which is thought to play a role in delaying the onset of puberty. Puberty is a complex process involving the coordination of various body systems and hormones.

The link between blue light exposure and decreased melatonin levels suggests that increased screen time may play a role in this increase, as happened during the pandemic restrictions. However, it is very difficult to assess this in children.

Blue light accelerates puberty

Therefore, this study used a rat model that divided them into three groups of six and exposed them to a normal light cycle or 6 or 12 hours of blue light. The first signs of puberty appeared significantly earlier in both groups exposed to blue light, and the longer the exposure, the earlier puberty occurred.

Rats exposed to blue light also showed a decrease in melatonin and an increase in specific reproductive hormones (estradiol and luteinizing hormone), as well as physical changes in ovarian tissue consistent with the onset of puberty. During the 12-hour exposure, the rats also had some signs of cellular damage and inflammation in the ovaries.