Effects of Sleeping with your lights on

A lot of children and some adults are afraid of falling asleep in total darkness. That is why very frequently they ask their parents to leave the light on in their bedroom. Some parents use special dim lights or special night light that are quite fine and usually do not cause any problems of disturbances. However, according to the studies of American and Japanese scientists, if a child sleeps with the regular, bright light, sooner or late this habit will have certain unwanted negative side effects on the child’s sleep routine and mental condition.
According to the findings of this research, the first negative effects of sleeping with the bright light one are developing sleep disorders, lower quality of sleep and sleep cycle irregularities, as well as hyperactivity, irritability, etc. Another study carried out by the specialists at the Scheie Eye Institute in Pennsylvania showed that the children who have a habit of sleeping with regular bright light have higher risks of being shortsighted. The experiments involving 480 children from 2 to 16 years old proved that sleeping with the light on is linked to 20% more increased risks of becoming shortsighted.
Finally, the specialists from Ohio University found out that the habit of sleeping with bright light on is also quite dangerous for adult people. The two-week experiment demonstrated that those adults who enjoy sleeping with the lights on have much higher risks to develop depression and other related psychological conditions. At that, in women these risks increase up to 30%. The specialists underline that similar effects can be received watching too much of TV programs before going to sleep. Therefore, they highly recommend avoid placing a TV in the bedroom.

Jan. 19, 2011 -- Exposure to artificial light after dusk and before bedtime may reduce sleep quality by suppressing production of the hormone melatonin and may also have other negative health effects, according to a new study.
Melatonin, produced by the brain’s pineal gland at night, regulates the sleep-wake cycle. It also has been shown to lower blood pressure and body temperature, says study researcher Joshua Gooley, PhD, of Brigham and Women’s Hospital and Harvard Medical School in Boston.
“On a daily basis, millions of people choose to keep lights on prior to bedtime and during the usual hours of sleep,” Gooley says in a news release. “Our study shows that this exposure to indoor light has a strong suppressive effect on the hormone melatonin. This could, in turn, have effects on sleep quality and the body’s ability to regulate body temperature, blood pressure and glucose levels.”
In the study, Gooley and colleagues evaluated 116 healthy volunteers between the ages of 18 and 30 who were exposed to room light or dim light in the eight hours prior to bedtime for five straight days.
Blood plasma was collected every 30 to 60 minutes via an intravenous catheter in the forearms of volunteers so that melatonin measurements could be taken.

Results were clear, showing that exposure to room light before bedtime shortened melatonin duration by about 90 minutes, compared to dim light exposure. In addition, the researchers say, exposure to room light during the usual hours of sleep suppressed melatonin levels by more than 50%.
“Given that chronic light suppression of melatonin has been hypothesized to increase relative risk for some types of cancer and that melatonin receptor genes have been linked to type 2 diabetes, our findings could have important health implications for shift workers who are exposed to indoor light at night over the course of many years,”