U.S. researchers reported that teenagers who did not get the required amount of sleep are at a substantially increased risk for pre-hypertension and high blood pressure. Reported in the American Heart Association journal Circulation, the report said that teens that slept less than 6 ½ hours a night stood twice the risk of high blood pressure, while teens with troubled sleep had tripled the risk.

Susan Redline, M.D., M.P.H., at Case Western Reserve University in Cleveland, Ohio and team found the pattern held even when adjusted for sex, weight and socioeconomic status.

"Our study underscores the high rate of poor quality and inadequate sleep in adolescence coupled with the risk of developing high blood pressure and other health problems," said Dr.Redline, the pediatrician who led the study."We also found that low sleep efficiency may be more consistently associated with pre-hypertension than a shorter sleep period."

Dr. Redline felt the reason for lack of sleep being common to most teens is due to the “invasion of electronic devices into the bedroom." Sleep is often sacrificed by teens because of the extensive electronic equipment that is common for them such as televisions, computers, stereos, iPods, and cell phones being the main diversion.

Dr. Redline's team studied 238 teens in the age group of 13-to-16-years and found 14 % of the adolescents had high blood pressure or readings which were borderline, a stage called pre-hypertension. In the case of adults, high blood pressure is defined as a reading of 140/90 or higher, while for children it is defined as being in the 90th percentile for their age.

High blood pressure can damage arteries and kidneys, leading to stroke, kidney disease and other illnesses.

On average, the teens got just 7.7 hours of sleep a night, whereas ideally teenagers need at least nine hours of sleep every night.  16 % of the teens had low sleep efficiency, which meant they had trouble falling asleep most of the time or woke up too early while another 11 % slept less than 6 1/2 hours a night.

"These associations may have a large public health impact," Redline said. "Part of the problem is the technological invasion of the bedroom with computers, cell phones and music."

The National Heart, Lung and Blood Institute, which is part of the National Institutes of Health, said, "Signs of not getting enough sleep or sleeping poorly include consistently taking more than 30 minutes to fall asleep, awakening more than a few times or for long periods each night, feeling sleepy during the day, or having trouble concentrating at school or at work." The other culprits could be caffeine and too-warm temperatures which also keep people awake.

Earlier studies had shown that poor sleep quality is associated with obesity and impaired glucose tolerance in pediatric patients. This is the first study of its kind and though it may not definitively show a link between poor sleep and high blood pressure, but current knowledge of the relationship between sleep and metabolism suggests such a relationship is likely.

The study may underestimate the problem as it never included children with known sleep disorders and other illnesses said Dr Redline.