Melatonin levels dropped by 78 percent on average in reaction to light at 5 to 40 lux, which is substantially lower than usual room light. Even 50 minutes after the light was turned off, melatonin levels in most kids did not rebound.

If you want your preschooler to get a decent night’s sleep, keep them away from screens and other sources of light an hour before bedtime, according to researchers.

According to a research team from the University of Colorado Boulder, even a small amount of light exposure can produce a significant decline in the sleep-promoting hormone melatonin.

“Our previous work showed that one, fairly high intensity of bright light before bedtime dampens melatonin levels by about 90% in young children,” says study first author Lauren Hartstein.

“With this study, we were very surprised to find high melatonin suppression across all intensities of light, even dim ones,” according to Hartstein.

Hartstein and her colleagues had 36 healthy youngsters aged 3 to 5 wear a wrist monitor for nine days to track their sleep and light exposure for the study.

To normalize the children’s body clocks, parents kept them on a consistent sleep pattern for the first seven days. On the seventh day, the researchers covered the windows with black plastic and lowered the lights in the children’s rooms to create a dark environment.

On the final day of the trial, the children were asked to play games on an illuminated table in the hour before night. The light intensity on the table varied between the kids, ranging from 5 to 5,000 lux. (A lux is defined as the light emitted by a candle held at a distance of about 3 feet.)

According to the study’s authors, saliva tests revealed that melatonin levels were 70 percent to 99 percent lower on the night when children were exposed to the light table than on the preceding evenings with minimal light.

According to a study published recently in the Journal of Pineal Research, there was little to no link between the brightness of the light on the previous night and the reductions in melatonin levels.

The results of study found that Melatonin levels dropped by 78 percent on average in reaction to light at 5 to 40 lux, which is substantially lower than usual room light. Melatonin did not rebound in most of the kids even after the light was turned off for 50 minutes.

Why are kids so light-sensitive?

Children’s eyes, the researchers reported, had larger pupils and more translucent lenses than adults’ eyes, allowing light to enter them more freely.

“Kids are not just little adults,” adds senior study author Monique LeBourgeois. “This heightened sensitivity to light may make them even more susceptible to dysregulation of sleep and the circadian system.”

Half of kids use screen media before bed, according to the researchers, and these findings should serve as a reminder to parents to switch off electronic devices and keep light to a minimum before bedtime to assist their children get a good night’s sleep.

Source: 10.1111/jpi.12780

Image Credit: Getty

You were reading: Even dim light can decrease sleep-promoting hormone melatonin by more than 70% in preschoolers