Light and Lower Sleep Hormone in Kids

woman-653892_640If you are having a hard time getting your teenager out of bed in the morning, you may want to restrict late night light exposure. A new research has shown that nighttime melatonin levels can be suppressed as much as 37 percent if young adolescents are exposed to bright lights before going to sleep. 

“The message is that we really have to be careful about protecting our especially young teens from light at night, which means parents need to get all screens out of the bedroom, because ultimately they can be quite damaging to a child’s capacity to get enough sleep,” said study co-author Mary Carskadon, professor of psychiatry and human behavior at Brown University’s Alpert Medical School, in Providence, R.I. That means high tech devices like smartphones, tablets and laptops viewed before bedtime can have an adverse effect on your kids.

Puberty brings on it’s own change in sleep habits, as teens desire later bedtime due to varying social pressures, but researchers believe biological factors are also playing a role as the internal sleep clock starts to shift. 

The study looked at early pubescent kids (ages 9-15 boy, 11-16 girls) who were exposed to an hour of light at four different brightness levels for four nights (11 p.m. or 3 a.m.). The levels ranged from dim “mood” lighting to bright light. 

Results showed melatonin readings were uniform during early morning light tests, but late night tests caused much greater melatonin suppression in younger adolescents. At the lower levels, melatonin was suppressed by more than 9 percent, while the bright light exposure exhibited a 37 percent suppression in melatonin. 

Although the study did not find that adolescents got less sleep from exposure to light before bedtime, they did find an effect on the sleep rhythms of young adolescents causing them to stay up later.“This study didn’t actually test how light affected sleep itself, but it did find that it causes a problem on the pathway to sleep by suppressing melatonin,” said Kelly Baron, director of the Behavioral Sleep Medicine Program at Northwestern University’s Feinberg School of Medicine in Chicago. 

Other studies have consistently shown that electronics in the bedroom are detrimental to both adults and kids. Which means that everyone should think about limiting their exposure to electronics and light before bedtime in order to optimize the quality of our sleep.

The study was published online in the Journal of Clinical Endocrinology & Metabolism.