With the academic year at the half-way mark, millions of high school students are preparing to take their mid-term exams. Unfortunately, research is increasingly showing that more and more teens are not getting enough sleep, which can have a negative impact on their grades. Teens are no longer adhering to "lights out". Among the reasons for these changes in sleeping patterns are increased part-time working hours, talking on the cell phone, computer usage and watching television at bedtime. According to the American Academy of Sleep Medicine (AASM), success on exams in the classroom is tied to sleep.

William Kohler, MD, medical director of the Florida Sleep Institute, director of pediatric sleep services at University Community Hospital in Tampa, and an AASM pediatric sleep expert, says that teens need more sleep than adults because their circadian rhythm is easily disrupted. An adequate quantity and quality of sleep is necessary for optimal learning, and Dr. Kohler encourages teens to establish appropriate bedtime hours and a healthy sleep environment to ensure at least nine to 10 hours of quality sleep.

"A student's performance in the classroom is dictated by the amount of sleep he or she gets the night before," says Dr. Kohler. "A teen who regularly gets enough sleep will have improved academic performance, a positive attitude towards their education, and be able to better interact socially with their peers and teachers. Students can also remember better what they learned if they get a good night's sleep after learning the task. Sleep deprivation, on the other hand, increases the incidence of academic failure, depression and behavioral problems."

Daniel S. Lewin, PhD, of the Children's National Medical Center at the George Washington University School of Medicine in Washington, D.C, agrees that, in today's society, in between school, after-school activities and socializing with friends, sleep often takes a back seat among teenagers.

"Weighing the importance of sleep and the essential activities is hard, and all too often in our current culture of achieve-achieve-achieve, sleep loses," says Dr. Lewin. "The bad news is that when sleep loses, you lose. Here's why: adequate sleep on a nightly basis is essential for learning, memory, safety and even preventing weight gain."

Dr. Lewin says that every now and then, a short sleep period is ok and even necessary, but some care should be exercised the next day because the less you sleep, the greater the risk of injury and getting into an automobile accident. Sleep loss night after night leads to poorer grades, difficulty getting along with friends and health problems in the long term, adds Dr. Lewin.

"As mid-term exams approach, remember that adequate sleep will lead to improved memory," says Dr. Lewin. "Do not stay up late cramming for the test the next day because there is a good probability that the loss of sleep will erode your performance, and last-minute bits of information will not help much. There is some good news. If you sleep for an adequate period of time, then rehearsing or practicing your test material at bedtime will be very likely to improve your recall."

Research has shown that inadequate and disruptive sleep can lead to problems with behavior and mood along with difficulty with cognition and performance in the classroom. A study published in a recent issue of the Journal of Clinical Sleep Medicine found that students who have trouble sleeping do not perform as well in school as students without sleep complaints.

Several recent studies outline the adverse effects of poor sleep among teens with regards to their success in school:

- Students with symptoms of sleep disorders are more likely to receive poor grades in classes such as math, reading and writing than peers without symptoms of sleep disorders.

- The brain responses of those children who don't get enough sleep can accurately predict the impact sleep loss has on their ability to pay attention during the course of a day.

- Research examining the impact of sleep in school-age children suggests that even mild sleep loss produces marked deficits in their cognitive development and functioning. Sleep restriction can alter children's initial stages of speech perception, which could contribute to disruptions in cognitive and linguistic functioning - skills necessary for reading and language development and comprehension.

- Teenagers who stay up late on school nights and make up for it by sleeping late on weekends are more likely to perform poorly in the classroom. This is because, on weekends, they are waking up at a time that is later than their internal body clock expects. The fact that their clock must get used to a new routine may affect their ability to be awake early for school at the beginning of the week when they revert back to their old routine.

- Aggressive behavior and bullying, common among schoolchildren, are likely to have multiple causes, one of which may be an undiagnosed sleep-related breathing disorder.

- Consuming caffeine may affect the sleep and school performance of young teens. Students who consume caffeine wake up later in the morning on school days. The study links waking up later for school with having a lower grade-point average. Students who consume caffeine later in the day also are more likely to miss school.

- Over the past decade, children have been going to bed later and sleeping less. This can be attributed, in part, to a lack of awareness in the community concerning sleep need in children and how the amount of sleep a child should get each night is dependent on one's age. The Sleep-Side Rule is found to be an effective classroom tool that improves children's understanding of the relationship between age and sleep need.

The following tips are provided by the AASM to help teens get the most out of their sleep. Parents should be aware of these guidelines and should use them to help their teen develop healthy sleep habits:

- Try to get close to nine hours of sleep each night. Get enough sleep so that you wake up refreshed and alert for the day.

- Try to wind down and relax before bedtime. Avoid intense studying, arguing and exercising. Stop playing video or computer games and enjoy some quiet time before bed.

- Avoid bright lights in the evening. Darkness lets your body know it's time to sleep.

- Try to get bright light in the morning. This helps reset your clock for the next night. Turn on bright lights and open your blinds when you get up. Getting exercise in the morning also may help.

- Try to catch up on any lost sleep when you can. Naps can be helpful to catch up with lost sleep, but don't nap in the evening. Sleeping later on weekends can help catch up with lost sleep. But do not sleep later than two to three hours past your normal weekday wake up time, especially on Sunday mornings.

- Avoid stimulants such as caffeine and nicotine in the afternoon and evening. Caffeine, nicotine, and alcohol can disturb your sleep. Do not drink alcohol. The combined effects of sleepiness with alcohol are very dangerous.

- Do not drive if you are sleepy. Driving sleepy can be as dangerous as driving drunk.

More information about "teens and sleep", including a new questionnaire that assesses the level of sleepiness in adolescents, is available from the AASM here.

SleepEducation.com, a Web site created by the AASM, provides information about various sleep disorders, the forms of treatment available, recent news on the topic of sleep, sleep studies that have been conducted and a listing of sleep facilities.

AASM is a professional membership organization dedicated to the advancement of sleep medicine and sleep-related research.

American Academy of Sleep Medicine