MONDAY, June 9 (HealthDay News) -- Teens who become addicted to their cell phones may be placing their health at risk by compromising their ability to sleep well, a new Swedish study suggests.

The finding was presented Monday at the Associated Professional Sleep Societies annual meeting, in Baltimore.

"The message is that adolescents who use their cell phones excessively are much more stressed, much more restless, much more fatigued, and have a greater tendency to develop sleep deprivation as a result of their calling habits," said study author Dr. Gaby Bader, an associate professor in the department of clinical neuroscience at Sahlgren's Academy in Goteburg.

Bader said he was "quite surprised" by the strength of the correlation between teen cell phone use and sleep problems. And, he pointed out, the current study is only one part of a broader ongoing effort to assess the impact of numerous forms of technology on adolescent sleep, including computers and handheld e-mail devices.

With respect to cell phones, he and his team focused on the experiences of 21 healthy Swedish boys and girls between the ages of 14 and 20. The teens kept what the authors described as "regular working/studying hours" and were not previously diagnosed with any particular sleep irregularity.

Based on self-reports, participants were divided into two groups: those sending or receiving five calls and/or short text messages (excluding e-mails) a day, and those using their cell phones 15 times or more on a daily basis.

Bader pointed out that while the average number of calls/texts per day hovered between 35 and 40, some of the above-15 call users used their cells with a frequency far more excessively -- approaching, at times, more than 200 calls and/or texts a day. Among all participants, only one reported turning off their cell phone at night, he noted.

All participants were asked to complete lifestyle questionnaires, describing sleep quality as well as self-perceptions regarding depression, anger, and self-esteem. In addition, each kept a sleep diary for one week.

The authors also conducted overnight at-home sleep inspections, as well as two-day cardiac activity assessments.

The researchers observed that the above-15 call group kept more irregular sleeping hours than the lower-use group, had more difficulty falling asleep, more difficulty waking up, and experienced more sleep disruptions.

Heavy cell phone users also consumed more beverages containing stimulants than the minimal phone-user group. This perhaps contributed to the finding that heavy callers also displayed more restlessness, stress, and fatigue than minimal users.

Bader said that among young people, a relatively recent technological innovation like the cell phone has quickly become nearly ubiquitous, giving rise to considerable pressure to keep in touch 24/7. And he suggested that this pressure can develop into an addiction, with serious negative ramifications for adolescent health.

"We see more and more people -- especially the young generation -- who grew up with these kinds of items and gadgets in their hands," Bader said. "And they become dependent on the technology. So, we have to teach young people to be structured. To know when to have the cell phone on, and when to switch it off. To avoid becoming the slave of technology, instead of the master."

Dr. Mary Carskadon, director of sleep and chronobiology research at E.P. Bradley Hospital in Providence, R.I., expressed little surprise with the finding.

"Interpersonal contact is one of the things that's best at keeping us awake," she observed. "And so, a young person receiving cell phone texts or phone calls, when their brain is saying, 'Let me sleep,' is going to have more sleep disturbances. And they are going to be tired and restless, and probably, as a result, going to use more stimulants. And judgment is not always the best in our teenage years. So, that's where I think parental attention to this issue may be useful."

More information

For more on teens and sleep, visit the Kidshealth.org.

SOURCES: Gaby Bader, M.D., consultant, London Clinic, and associate professor, Department of Clinical Neuroscience, Sahlgren's Academy, University of Goteburg, Sweden; Mary Carskadon, M.D., professor, psychiatry and human behavior, Warren Alpert Medical School, Brown University, and director, sleep and chronobiology research, E.P. Bradley Hospital, Providence, R.I.; June 9, 2008, presentation, Associated Professional Sleep Societies, annual meeting, Baltimore

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