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Poor sleep in teens linked to higher blood pressure

August 19, 2008

Teenagers are notorious for having bad sleep habits. New research suggests that having trouble staying awake the next day might not be the only consequence they face. In the first study to look at the relationship between not getting enough sleep and blood pressure in healthy adolescents, researchers found that healthy teens (ages 13 to 16 years old) who slept less than 6.5 hours a night were 2.5 times more likely to have elevated blood pressure compared to those who slept longer. In addition, those with poor sleep, or low sleep efficiency - having trouble falling asleep or staying asleep - had, on average, 4 mm Hg higher systolic blood pressure (the top number) and were 3.5 times more likely to have prehypertension or hypertension than their peers who slept well. Untreated high blood pressure can increase the risk for stroke and other cardiovascular diseases later in life.

"Sleep Quality and Elevated Blood Pressure in Adolescents" is published online in the August 19 issue of Circulation: Journal of the American Heart Association. The study was supported by the National Heart, Lung, and Blood Institute (NHLBI) of the National Institutes of Health.

The findings are from a cross-sectional analysis of 238 adolescents ages 13 to 16 years old (average age of 14) enrolled in the Cleveland Children's Sleep and Health Study. Sleep efficiency and duration was evaluated at home for three to seven nights, where teens completed a daily sleep log and wore a wrist device that measures movement to determine sleep and wake cycles. Participants also spent one night in a clinical sleep lab, where, in addition to assessing sleep with standard devices, staff measured blood pressure nine times throughout their visit.

Participants did not have sleep-disordered breathing or other known health conditions. Results were adjusted for gender, body mass index (an indicator of overweight or obesity), and socioeconomic status.

These results are similar to findings from other studies in adults and suggest that poor sleep may be associated with significant health consequences for adolescents. However, larger studies and analyses with blood pressure measurements repeated over time, as recommended by the NHLBI guidelines on high blood pressure in children and adolescents (http://www.nhlbi.nih.gov/health/prof/heart/hbp/hbp_ped.htm), are needed to confirm these findings.

Michael J. Twery, PhD, director of the NHLBI National Center on Sleep Disorders Research, is available to comment on this study and on the importance of adequate and good quality sleep.

In general, adolescents need at least 9 hours of sleep a night to function at their best. However, many teens (as well as adults) regularly sleep less. In this study, participants slept on average 7.7 hours a night, with 11 percent sleeping 6.5 hours or less a night.

The biological drive to sleep peaks later in the night during adolescence compared to other age groups. Combined with the daily need for 9 hours of sleep, teens face unique challenges for getting sufficient sleep while meeting typical daytime schedules.

In addition, many factors that contribute to poor sleep -- for example, stress, caffeine, nicotine, noise, bright lights, or an uncomfortable (eg, too warm) room temperature -- can be prevented. TVs and computers in the bedroom can greatly interfere with sleep - and are especially common among teens.

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.

Keeping a daily sleep log, or diary, can help you track your sleep habits and identify what might be interfering with sleep. For a sample sleep diary and tips for getting a good night's rest, see NHLBI's Your Guide to Healthy Sleep (http://www.nhlbi.nih.gov/health/public/sleep/healthy_sleep.htm)

NIH/National Heart, Lung and Blood Institute