Bedtime gadgets suppress melatonin production in children

Sci­en­tists from the Uni­ver­si­ty of Col­orado in Boul­der believe that light before falling asleep and dur­ing sleep is much more harm­ful for chil­dren than for adults, as it leads to a sharp drop in the pro­duc­tion of mela­tonin, the sleep hor­mone.

Chil­dren’s eyes have larg­er pupils and a more trans­par­ent lens than those of adults. It has been proven, for exam­ple, that blue light pass­es through a baby’s eye 1.2 times bet­ter than through an adult’s eye.

The study involved 36 3–5‑year-olds. For 9 days, sci­en­tists tracked their sleep and reac­tion to light using a wrist mon­i­tor. For a week, the chil­dren lived on a set sched­ule to set their cir­ca­di­an clock to pro­duce the sleep hor­mone.

On the 8th day, the rooms where the chil­dren lived turned into a “cave” with­out access to exter­nal light. Sali­va sam­ples were tak­en from the sub­jects dur­ing the day dur­ing wake­ful­ness and the mela­tonin index was mea­sured. On the 9th day, the chil­dren sat in gad­gets before going to bed. The illu­mi­na­tion inten­si­ty var­ied from 5 to 5000 lux.

Accord­ing to the data obtained, even in very low light, mela­tonin pro­duc­tion was sup­pressed by 70–99% com­pared to the norm.

It is impor­tant that, unlike adults, the rela­tion­ship between the bright­ness of light and the degree of sup­pres­sion of mela­tonin pro­duc­tion was not revealed in babies. Even with light­ing of 5–40 lux, which is sig­nif­i­cant­ly dim­mer than the usu­al light in the room, mela­tonin began to be pro­duced 78% worse. The pro­duc­tion of the sleep hor­mone did not recov­er even 50 min­utes after the black­out.

Sci­en­tists believe that this does not mean the imme­di­ate aban­don­ment of night­lights and the tran­si­tion to falling asleep in com­plete dark­ness. But this def­i­nite­ly means that you should aban­don any gad­gets an hour before bed­time and reduce light­ing when falling asleep to a min­i­mum.