If your child is having a hard time falling asleep, tell her to forget about counting sheep and hang up her cellphone instead.
A new study presented yesterday at SLEEP 2008, the Annual Meeting of the Associated Professional Sleep Societies, found teenagers who use their cellphones excessively are more prone to disrupted sleep, restlessness, stress and fatigue.
"It is necessary to increase the awareness among youngsters of the negative effects of excessive mobile phone use on their sleep-wake patterns," wrote Gaby Badre, the study's author, adding that lack of sleep can have health risks and affect attention and cognitive abilities.
The study, which adds to a growing body of research about the impact of cellphones on sleep patterns, followed 21 subjects between the ages of 14 and 20, all of whom had regular schedules and no history of sleep problems.
The participants were divided into two groups, one that made less than five calls and/or text messages a day, and the other that made more than 15 calls and/or text messages a day.
The teens were also asked to keep sleep diaries and answer questionnaires about their lifestyle and sleep habits.
According to the results, the young people who used their cellphones excessively had increased restlessness, consumed more energy drinks, had difficulty falling asleep and were more susceptible to stress and fatigue.
One of the subjects sent more than 200 text messages a day. Only one teen turned their cellphone off at night.
Members of the group with the high number of calls woke up more regularly in the night, were more likely to toss and turn, had a harder time getting up in the morning and were more tired before midday. On the weekend, seven of the 11 teens who made the high number of calls woke up after noon. Only two from the other group woke up so late.
It is recommended that adolescents get nine hours of sleep a night.
This is not the first time cellphones have been linked to wakeful nights.
In January, another study, by Wayne State University School of Medicine in Detroit and researchers from Uppsala University in Sweden, found that radiation released by cellphones appeared to cause insomnia, headaches and difficulties in concentration.
The 18-month study followed 35 men and 36 women between the ages of 18 and 45, some of whom were exposed to radiation that mimicked levels received when using cellular phones.
"The ones who were exposed reported headaches, it took longer for them to fall asleep and they did not sleep as well through the night," concluded Bengt Arnetz, who led the study.
The American Academy of Sleep Medicine offered the following tips on how to get a good night's sleep. Surprisingly, they did not recommend turning off your
Follow a consistent bedtime routine.
Avoid foods or drinks that
contain caffeine, and any
medicine that has a stimulant, prior to bedtime.
Do not stay up all night to "cram" for an exam or do
Keep computers and TVs out of the bedroom.