The Role of Sleep Deprivation on Academic Performance in Teens

A survey of sleep-deprived teens finds they think that a later start time for school and tests given later in the school day would result in better grades. The survey was presented at the American Thoracic Society 2007 International Conference, on Sunday, May 20.The survey of 280 high school students confirmed what most parents with a teenager know: they are not getting enough sleep. More sleep would translate into improved academic performance, according to the teens questioned. They all attended Harriton High School in suburban Philadelphia, where the school day begins at 7:30 a.m. and ends at 2:25 p.m.

The survey found that:

• 78% of students said it was difficult to get up in the morning
• Only 16% said they regularly had enough sleep
• 70% thought their grades would improve if they had more sleep
• 90% thought their academic performance would improve if school were to start later

The surveyed teens said they do not feel alert while taking tests during early morning periods, and they do not think they can perform at the pinnacle of their ability during the early morning hours. Most students said they thought the best time to take a test would be from 11 a.m. to 1 p.m. They thought they would perform better academically and that their grades would improve if they could sleep longer.

Richard Schwab, M.D., of the University of Pennsylvania, conducted the study with his daughter Amanda, one of the sleep-deprived teens who attended Harriton High School. “I watched her get up early for four years, and saw how difficult it was,” Dr. Schwab says. “Teenagers need more sleep than adults and their circadian rhythms are phase shifted so that their ideal bedtime is midnight to 1:00 a.m.; yet they have to get up at 6:30 or earlier for high school.

While adults usually need 7 to 8 hours of sleep, teens need 8 to 9 hours, he says. In addition, teens go to bed much later – their biological clock often keeps them up until 1 a.m. to 2 a.m. Because they have to get up so early for school, many teens achieve only 6 ½ to 7 hours of sleep or, in some cases, much less. That means they tend to sleep in on the weekends, often until 11 am or later, to try to make up for their sleep deficit.

“Right now, high schools usually start earlier in the morning than elementary schools. But if school start times were based on sleep cycles, elementary schools should start at 7:30 and high schools at 8:30 or 8:45 – right now it’s the reverse. School systems should be thinking about changing their start times. It would not be easy—they would have to change the busing system—but it would increase their student’s sleep time and likely improve their school performance.”

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Article adapted by MD Only Weblog from original press release.
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Contact: Suzy Martin
American Thoracic Society

How Exercise Stops Memory Loss

Research has shown that people who exercise do better on memory tests. Now a new Columbia University Medical Center study explains specifically what exercise does within the brain. Exercise, the researchers found, targets a region of the brain within the hippocampus, known as the dentate gyrus, which underlies normal age-related memory decline that begins around age 30 for most adults.

This finding is significant because it was accomplished via the first-ever observation of neurogenesis, the growth of neurons, within a living brain. Using an MRI imaging technique developed at Columbia, the researchers were able to identify neurogenesis within the dentate gyrus region following exercise. Previously, researchers were only able to prove neurogenesis upon postmortem exam in animal studies.

“No previous research has systematically examined the different regions of the hippocampus and identified which region is most affected by exercise,” said Scott A. Small, M.D., associate professor of neurology at Columbia University Medical Center and the study’s lead author. “I, like many physicians, already encourage my patients to get active and this adds yet another reason to the long list of reasons why exercise is good for overall health.”

Published in the March 12-16, 2007 early online edition of the Proceedings of the National Academy of Sciences, the finding builds upon previous research at Columbia that identified the role of the dentate gyrus region of the hippocampus in normal age-related memory decline. Additionally, Fred “Rusty” Gage, Ph.D. of the Salk Institute, a lead co-investigator on this study, had demonstrated in mice that the dentate gyrus is the one area of the brain where new neurons are generated, and that exercise improves this process. This is the first human study to emerge out of this observation.

“Our next step is to identify the exercise regimen that is most beneficial to improve cognition and reduce normal memory loss, so that physicians may be able to prescribe specific types of exercise to improve memory,” said Dr. Small, who is also a research scholar at the Columbia University Taub Institute for Research on Alzheimer’s Disease and the Aging Brain.

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Article adapted by MD Only Weblog from original press release.
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Contact: Elizabeth Streich, Columbia University Medical Center

Additional Columbia researchers who contributed to this study include: Ana C. Pereira, Rene Hen, Dan E. Huddleston, Adam M. Brickman, Alexander A. Sosunov, Guy M. McKhann, Truman R. Brown and Richard Sloan.

The Taub Institute for Research on Alzheimer’s Disease and the Aging Brain at Columbia University Medical Center is a multidisciplinary group that has forged links between researchers and clinicians to uncover the causes of Alzheimer’s, Parkinson’s and other age-related brain diseases and discover ways to prevent and cure these diseases. It has partnered with the Gertrude H. Sergievsky Center at Columbia University Medical Center which was established by an endowment in 1977 to focus on diseases of the nervous system. The Center integrates traditional epidemiology with genetic analysis and clinical investigation to explore all phases of diseases of the nervous system.

Columbia University Medical Center provides international leadership in basic, pre-clinical and clinical research, in medical and health sciences education, and in patient care. The medical center trains future leaders and includes the dedicated work of many physicians, scientists, nurses, dentists, and public health professionals at the College of Physicians & Surgeons, the College of Dental Medicine, the School of Nursing, the Mailman School of Public Health, the biomedical departments of the Graduate School of Arts and Sciences, and allied research centers and institutions.

Magnesium shown to reverse memory loss

Magnesium helps build bones, make proteins, release energy stored in muscles and regulate body temperature. In the cover story of the Dec. 2 issue of Neuron, MIT researchers report a possible new role for magnesium: helping maintain memory function in middle age and beyond.

The adult daily nutritional requirement for magnesium, a trace mineral found in foods such as dark green, leafy vegetables, is around 400 mg a day. But studies show that as many as half of all Americans do not consume enough magnesium. Magnesium deficits have been tied to allergies, asthma, attention deficit disorder, anxiety, heart disease, muscle cramps and other conditions.

Associate Professor Guosong Liu and postdoctoral associate Inna Slutsky at MIT’s Picower Center for Learning and Memory found that magnesium helps regulate a key brain receptor important for learning and memory. Their work provides evidence that a magnesium deficit may lead to decreased memory and learning ability, while an abundance of magnesium may improve cognitive function.

“Our study shows maintaining proper magnesium in the cerebrospinal fluid is essential for maintaining the plasticity of synapses,” the authors wrote. “Since it is estimated that the majority of American adults consume less than the estimated average requirement of magnesium, it is possible that such a deficit may have detrimental effectsSresulting in potential declines in memory function.”

Plasticity, or the ability to change, is key to the brain’s ability to learn and remember. Synapses, the connections among brain cells, undergo physical changes in response to brain activity. While the mechanisms underlying these changes remain elusive, it is known that synapses are less plastic in the aging or diseased brain. Loss of plasticity in the hippocampus, where short-term memories are stored, causes the forgetfulness common in older people.

“The important issue is how the plasticity of synapses is regulated physiologically,” said Liu, who has appointments in MIT’s Department of Biology and Department of Brain and Cognitive Sciences. Working with Slutsky, graduate student Safa Sadeghpour and technician Bing Li, Liu identified a key principle that predicts which chemicals can enhance plasticity.

This finding is akin to the difference between hearing music on an old radio or a high-fidelity stereo. Synapses, like speakers, have a level of background noise that can get in the way of transmitting their signal from one neuron to another. Just as our ears become more sensitive to nuances in music played on a top-of-the-line music system, synapses become more plastic when background noise is reduced.

Armed with this new understanding, the researchers then identified magnesium’s importance in synaptic function.

Magnesium is the gatekeeper for the NMDA receptor, which receives signals from an important excitatory neurotransmitter involved in synaptic plasticity. Magnesium helps the receptor open up for meaningful input and shut down to background noise. “As predicted by our theory, increasing the concentration of magnesium and reducing the background level of noise led to the largest increases of plasticity ever reported in scientific literature,” Liu said.

The researchers have identified and are now studying several families of drugs that may restore learning and memory in animals. Most important, Liu said, “This new theory may help create strategies to prevent aging-induced loss of synaptic plasticity.”

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Article adapted by MD Only Weblog from original press release.
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Contact: Sean Wagner
MIT News Office
Massachusetts Institute of Technology
Room 11-400
77 Massachusetts Avenue
Cambridge, MA 02139-4307
Phone: 617-253-2700
http://web.mit.edu/newsoffice/www

This work was supported by the RIKEN-MIT Neuroscience Center and the National Institutes of Health.

A version of this article appeared in MIT Tech Talk (download PDF).

Memory Loss… Cognitive Decline and Dementia Linked to Diet

Research has shown convincing evidence that dietary patterns practiced during adulthood are important contributors to age-related cognitive decline and dementia risk. An article published in Annals of the New York Academy of Sciences highlights information on the benefits of diets high in fruit, vegetables, cereals and fish and low in saturated fats in reducing dementia risk.

Adults with diabetes are especially sensitive to the foods they eat with respect to cognitive function. Specifically, an adult with diabetes will experience a decline in memory function after a meal, especially if simple carbohydrate foods are consumed. While the precise physiological mechanisms underlying these dietary influences are not completely understood, the modulation of brain insulin levels likely contributes.

This deficit can be prevented through healthful food choices at meals. The findings suggest that weight maintenance reduces the risk of developing obesity-associated disorders, such as high blood pressure and high cholesterol, and is an important component of preserving cognitive health.

The work shows another benefit of maintaining healthful eating practices with aging – the same ones proposed by most diabetes and heart & stroke foundations. “This type of information should be able to empower the individual, knowing that he/she can be actively engaged in activities and lifestyles that should support cognitive health with aging,” says Carol Greenwood, author of the study.

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Article adapted by MD Only Weblog from original press release.
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Contact: Sean Wagner
http://www.blackwellpublishing.com

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This study, entitled “Dietary Influences on Cognitive Function with Aging,” is published in volume 1114 of the Annals of the New York Academy of Sciences: Healthy Aging and Longevity.

To view the abstract for this article, please http://www.blackwell-synergy.com/doi/abs/10.1111/j.1468-0009.2007.00496.x http://www.blackwell-synergy.com/doi/abs/10.1111/j.1540-627X.2007.00220.x http://www.blackwell-synergy.com/doi/abs/10.1111/j.1523-536X.2007.00172.x http://www.blackwell-synergy.com/">click here.