New Delhi, Mar 07 (ANI): Turns out, preschoolers exposed to nighttime light tend to sleep lesser. According to a University of Colorado at Boulder study, exposing preschoolers to an hour of bright light before bedtime almost completely shuts down their production of the sleep-promoting hormone melatonin and keeps it suppressed for at least 50 minutes after lights out. "Although the effects of light are well studied in adults, virtually nothing is known about how evening light exposure affects the physiology, health, and development of preschool-aged children," said lead author Lameese Akacem. "In this study, we found that these kids were extremely sensitive to light." "Light is our brain clock's primary timekeeper", explained senior author Monique LeBourgeois. "We know younger individuals have larger pupils, and their lenses are more transparent. This heightened sensitivity to light may make them even more susceptible to dysregulation of sleep and the circadian clock", continued LeBourgeois. She explained that when the light hits the retina in the eye in the evening, it produces a cascade of signals to the circadian system to suppress melatonin and push back the body's entrance into its "biological night". For preschoolers, this may not only lead to trouble falling asleep one night, but to chronic problems feeling sleepy at bedtime. The study is published in the journal Physiological Reports.