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NEW YORK (Reuters Health) - Caffeine-fueled teens are texting, Web-surfing and gaming for hours into the night, which is affecting their alertness and ability to function during the day, a new study in Pediatrics shows.
"They're up at night and they're dong a lot less homework than we thought and a lot more multitasking," Dr. Christina J. Calamaro of Drexel University in Philadelphia, the lead researcher on the study, told Reuters Health.
She and her colleagues found that the more multitasking a teen did, the more likely he or she was to be dozing off during the day, while the kids who nodded off were also the heaviest caffeine consumers.
Experts believe that teenagers need at least nine hours of sleep every night, Calamaro and her team note in their report, but the average sleep time for US adolescents is seven hours. The researchers investigated whether teens' use of technology and caffeinated beverages might affect how much sleep they got at night and how tired they felt during the day by surveying 100 12- to 18-year-olds.
To gauge how heavily the study participants used technology at night, Calamaro and her colleagues developed a measure they dubbed the "multitasking index": the total number of hours a child spent doing each of nine different activities (watching TV, listening to MP3s, doing homework, and watching DVDs or videos, etc.) divided by 9 -- the number of hours from 9 p.m. to 6 a.m.
Kids' average multitasking index was about .6, meaning they were engaged in the equivalent of one of the nine activities for 5.3 hours or four activities for an 80 minutes each.
Just one in five of the study participants said they got 8 to 10 hours of sleep a night, and these teens had an average multitasking index of 0.39.
One third of the study participants said they fell asleep in school, and these teens dozed off an average of twice a day, although some said they fell asleep as many as eight times a day. The higher a child's multitasking index, the more likely he or she was to fall asleep in school.
The teens' average caffeine consumption was 215 mg daily, or the equivalent of a couple of espressos.
Nearly three-quarters of the study participants were drinking more than 100 mg of caffeine a day, and there were a few with very heavy consumption, the researchers found; 11.2% drank over 400 mg of caffeine daily. One student reported drinking over 1,400 mg of caffeine every day.
Fourteen of the study participants had their licenses, and half of them said they felt sleepy while driving; one of them admitted to falling asleep behind the wheel.
"These adolescents who multitask the most are at risk for changes in school performance, difficulties with executive function, and degradation of neurobehavioral function," Calamaro and her team warn.
The researcher said that while the current study was small, she expects the findings accurately reflect teen behavior. "I won't be surprised if and when we replicate this that we'll get similar results, because this is what adolescents are doing."
Parents need to take steps to keep their children's nighttime technology use under control, Calamaro said in an interview. It's crucial to keep TVs, computers and especially cell phones out of kids' bedrooms, she said. "The texting is a huge issue. I think we'll find it to be a greater issue."
Parents should also discourage teens from drinking caffeinated beverages after noon, the researcher added.
While teen's body clocks may force them to stay up somewhat later than adults, and wake up later too, it's still important for adults to convey the message that night is time to start slowing down, Calamaro added. "Even though we know adolescents are on a different time schedule, we can still get them less wired at night."
SOURCE: Pediatrics, June 2009.