Bright lights in hour before bedtime keep preschoolers awake, study finds

With clearer lenses and wider pupils, preschoolers' eyes are more sensitive than adults eyes are to bright lights and exposure to those lights before bedtime all but shuts down their production of sleep-producing melatonin, according to researchers at the University of Colorado Boulder.

The findings published in the journal Physiological Reports mirror findings of studies involving late-night light exposure and adult sleep habits , only more so.

The researchers' advice to parents: dim the lights an hour before children's bedtime to improve their sleep habits. Also minimize their pre-bedtime exposure to computer and TV screens.

“Light is our brain clock's primary timekeeper,” Monique LeBourgeois, an associate professor in the Department of Integrative Physiology, said in the university's article describing the study's findings.

Melatonin also plays a role in other bodily processes like regulating body temperature, blood pressure and metabolizing sugar, so the effects of bright lights before bedtime go beyond sleep, researchers said.