Aerobic Fitness, Hormones Predict Recognition Memory in Young Adults
Dec. 2, 2013 —
Science Daily/Boston University School of Medicine (BUSM)
Researchers at Boston University School of Medicine (BUSM) have found further evidence that exercise may be beneficial for brain health and cognition. The findings, which are currently available online in Behavioural Brain Research, suggest that certain hormones, which are increased during exercise, may help improve memory.
Hormones called growth factors are thought to mediate the relationship between exercise and brain health. The hippocampus, a region of the brain crucial for learning and memory, is thought to be uniquely affected by these hormones.
The growth factors brain-derived neurotrophic factor (BDNF), vascular endothelial growth factor (VEGF), and insulin-like growth factor-1 (IGF-1), have been implicated in the link between exercise and hippocampal function. BDNF, for example, acts on the nervous system to help regulate communication between existing brain cells (neurons) and stimulate the growth and maturation of new hippocampal neurons and blood vessels.
In this study, the researchers recruited healthy young adults, in whom they measured blood hormone levels together with performance on a recognition memory task and aerobic fitness. The researchers were thus able to correlate the blood hormone levels with aerobic fitness, and subsequently whether there was any effect on memory function.
According to the researchers, BDNF and aerobic fitness predicted memory in an interactive manner, suggesting that at low fitness BDNF levels negatively predicted expected memory accuracy. Conversely, at high fitness resting BDNF levels positively predicted recognition memory. There also was a strong association between IGF-1 and aerobic fitness; however there was no complementary link between IGF-1 and memory function.
"We will be continuing this line of research by testing if memory improves following an exercise training program in both young and geriatric adults, and by adding brain imaging techniques," explained Karin Schon, PhD, assistant professor of anatomy and neurobiology at BUSM, who served as the study's principal investigator.
http://www.sciencedaily.com/releases/2013/12/131202162204.htm
Scientists identify protein linking exercise to brain health
October 10, 2013
Science Daily/Dana-Farber Cancer Institute
A protein that is increased by endurance exercise has been isolated and given to non-exercising mice, in which it turned on genes that promote brain health and encourage the growth of new nerves involved in learning and memory, report scientists from Dana-Farber Cancer Institute and Harvard Medical School.
The findings, reported in the journal Cell Metabolism, help explain the well-known capacity of endurance exercise to improve cognitive function, particularly in older people. If the protein can be made in a stable form and developed into a drug, it might lead to improved therapies for cognitive decline in older people and slow the toll of neurodegenerative diseases such Alzheimer's and Parkinson's, according to the investigators.
"What is exciting is that a natural substance can be given in the bloodstream that can mimic some of the effects of endurance exercise on the brain," said Bruce Spiegelman, PhD, of Dana-Farber and HMS. He is co-senior author of the publication with Michael E. Greenberg, PhD, chair of neurobiology at HMS.
The Spiegelman group previously reported that the protein, called FNDC5, is produced by muscular exertion and is released into the bloodstream as a variant called irisin. In the new research, endurance exercise -- mice voluntarily running on a wheel for 30 days -- increased the activity of a metabolic regulatory molecule, PGC-1α, in muscles, which spurred a rise in FNDC5 protein. The increase of FNDC5 in turn boosted the expression of a brain-health protein, BDNF (brain-derived neurotrophic protein) in the dentate gyrus of the hippocampus, a part of the brain involved in learning and memory.
It has been found that exercise stimulates BDNF in the hippocampus, one of only two areas of the adult brain that can generate new nerve cells. BDNF promotes development of new nerves and synapses -- connections between nerves that allow learning and memory to be stored -- and helps preserve the survival of brain cells.
How exercise raises BDNF activity in the brain wasn't known; the new findings linking exercise, PGC-1α, FNDC5 and BDNF provide a molecular pathway for the effect, although Spiegelman and his colleagues suggest there are probably others.
Having shown that FNDC5 is a molecular link between exercise and increased BDNF in the brain, the scientists asked whether artificially increasing FNDC5 in the absence of exercise would have the same effect. They used a harmless virus to deliver the protein to mice through the bloodstream, in hopes the FNDC5 could reach the brain and raise BDNF activity. Seven days later, they examined the mouse brains and observed a significant increase in BDNF in the hippocampus.
"Perhaps the most exciting result overall is that peripheral deliver of FNDC5 with adenoviral vectors is sufficient to induce central expression of Bdnf and other genes with potential neuroprotective functions or those involved in learning and memory," the authors said. Spiegelman cautioned that further research is needed to determine whether giving FNDC5 actually improves cognitive function in the animals. The scientists also aren't sure whether the protein that got into the brain is FNDC5 itself, or irisin, or perhaps another variant of the protein.
http://www.sciencedaily.com/releases/2013/10/131010204803.htm
Exercise may be the best medicine for Alzheimer's disease
July 30, 2013
Science Daily/University of Maryland
Regular, moderate exercise could improve memory and cognitive function in those at risk for Alzheimer's disease in a way no drug can. Scientists studied the effects of exercise on a group of older adults with mild cognitive impairment and found that brain activity associated with memory, measured by neuroimaging, improved after 12 weeks of a moderate exercise program.
New research out of the University of Maryland School of Public Health shows that exercise may improve cognitive function in those at risk for Alzheimer's by improving the efficiency of brain activity associated with memory. Memory loss leading to Alzheimer's disease is one of the greatest fears among older Americans. While some memory loss is normal and to be expected as we age, a diagnosis of mild cognitive impairment, or MCI, signals more substantial memory loss and a greater risk for Alzheimer's, for which there currently is no cure.
The study, led by Dr. J. Carson Smith, assistant professor in the Department of Kinesiology, provides new hope for those diagnosed with MCI. It is the first to show that an exercise intervention with older adults with mild cognitive impairment (average age 78) improved not only memory recall, but also brain function, as measured by functional neuroimaging (via fMRI). The findings are published in the Journal of Alzheimer's Disease.
"We found that after 12 weeks of being on a moderate exercise program, study participants improved their neural efficiency -- basically they were using fewer neural resources to perform the same memory task," says Dr. Smith. "No study has shown that a drug can do what we showed is possible with exercise."
Recommended Daily Activity: Good for the Body, Good for the Brain
Two groups of physically inactive older adults (ranging from 60-88 years old) were put on a 12-week exercise program that focused on regular treadmill walking and was guided by a personal trainer. Both groups -- one which included adults with MCI and the other with healthy brain function -- improved their cardiovascular fitness by about ten percent at the end of the intervention. More notably, both groups also improved their memory performance and showed enhanced neural efficiency while engaged in memory retrieval tasks.
The good news is that these results were achieved with a dose of exercise consistent with the physical activity recommendations for older adults. These guidelines urge moderate intensity exercise (activity that increases your heart rate and makes you sweat, but isn't so strenuous that you can't hold a conversation while doing it) on most days for a weekly total of 150 minutes.
Measuring Exercise's Impact on Brain Health and Memory
One of the first observable symptoms of Alzheimer's disease is the inability to remember familiar names. Smith and colleagues had study participants identify famous names and measured their brain activation while engaged in correctly recognizing a name -- e.g., Frank Sinatra, or other celebrities well known to adults born in the 1930s and 40s. "The task gives us the ability to see what is going on in the brain when there is a correct memory performance," Smith explains.
Tests and imaging were performed both before and after the 12-week exercise intervention. Brain scans taken after the exercise intervention showed a significant decrease in the intensity of brain activation in eleven brain regions while participants correctly identified famous names. The brain regions with improved efficiency corresponded to those involved in the pathology of Alzheimer's disease, including the precuneus region, the temporal lobe, and the parahippocampal gyrus.
The exercise intervention was also effective in improving word recall via a "list learning task," i.e., when people were read a list of 15 words and asked to remember and repeat as many words as possible on five consecutive attempts, and again after a distraction of being given another list of words.
"People with MCI are on a very sharp decline in their memory function, so being able to improve their recall is a very big step in the right direction," Smith states.
The results of Smith's study suggest that exercise may reduce the need for over-activation of the brain to correctly remember something. That is encouraging news for those who are looking for something they can do to help preserve brain function.
Dr. Smith has plans for a larger study that would include more participants, including those who are healthy but have a genetic risk for Alzheimer's, and follow them for a longer time period with exercise in comparison to other types of treatments. He and his team hope to learn more about the impact of exercise on brain function and whether it could delay the onset or progression of Alzheimer's disease.
http://www.sciencedaily.com/releases/2013/07/130730123249.htm
Exercise can reduce stroke risk
July 18, 2013
Science Daily/University of Alabama at Birmingham
A new study from researchers at the University of Alabama at Birmingham (UAB) is one of the first to study the relationship between exercise and stroke in a large biracial cohort of men and women in the United States. The findings are published in the American Heart Association Journal Stroke.
Using 27,000 stroke-free blacks and whites ages 45 and older in the United States from the Reasons for Geographic and Racial Differences in Stroke (REGARDS) study cohort, researchers examined the association of self-reported physical activity with incident of stroke.
Participants were classified at baseline as being in active (i.e., no workouts in a typical week), moderately active (workouts one to three times per week) or vigorously active (workouts more than four times per week), and they were followed for an average of 5.7 years.
The results showed that physical inactivity was reported by 33 percent of participants and was associated with a 20 percent increased risk of stroke. Those who reported they exercised at least four times a week were less likely to experience a stroke or mini-stroke. Among men, only those who exercised four or more times a week had a lower stroke risk. Among women, the relationship between stroke and frequency of activity was less clear.
"The protective effect of intense physical activity may be through its impact on traditional risk factors such as hypertension and diabetes," explained Virginia Howard, Ph.D., UAB professor of epidemiology and senior study author.
"These findings confirm past results of studies done in only men or only women in limited geographical areas," Howard said. "By using the REGARDS cohort, our study was able to use a larger and more diverse population to show that participating in regular physical activity is associated with lower stroke risk."
Howard added that stroke is preventable, and physical activity is a major modifiable risk factor for stroke. "This should be emphasized more in routine physician check-ups, along with general education on the proven health benefits of regular physical activity on other stroke-risk factors including high blood pressure, diabetes and obesity," Howard said.
Study limitations highlighted include that the results are based on self-reported levels of physical activity, and self-reported data may not be a reflection of the truth. Also, investigators did not have data on the type or duration of the exercise in which people engaged, nor the number of sessions. Howard suggested future studies should consider different ways to measure physical activity through: use of more questions; devices such as accelerometers and heart monitors that can provide more objective data; and capturing information on other dimensions of physical activity such as frequency, intensity and duration.
http://www.sciencedaily.com/releases/2013/07/130718130456.htm
Eating More Berries May Reduce Cognitive Decline in the Elderly
April 26, 2012
Science Daily/Wiley-Blackwell
Blueberries and strawberries, which are high in flavonoids, appear to reduce cognitive decline in older adults according to a new study recently published in Annals of Neurology, a journal of the American Neurological Association and Child Neurology Society. The study results suggest that cognitive aging could be delayed by up to 2.5 years in elderly who consume greater amounts of the flavonoid-rich berries.
Flavonoids are compounds found in plants that generally have powerful antioxidant and anti-inflammatory properties. Experts believe that stress and inflammation contribute to cognitive impairment and that increasing consumption of flavonoids could mitigate the harmful effects. Previous studies of the positive effects of flavonoids, particularly anthocyanidins, are limited to animal models or very small trials in older persons, but have shown greater consumption of foods with these compounds improve cognitive function.
According to the 2010 U.S. Census, elderly Americans -- those 65 years of age and older -- increased by 15% between 2000 and 2010, faster than the total U.S. population, which saw a 9.7% increase during the same time period. "As the U.S. population ages, understanding the health issues facing this group becomes increasingly important," said Dr. Elizabeth Devore with Brigham and Women's Hospital and Harvard Medical School in Boston, Mass. "Our study examined whether greater intake of berries could slow rates of cognitive decline."
The research team used data from the Nurses' Health Study -- a cohort of 121,700 female, registered nurses between the ages of 30 and 55 who completed health and lifestyle questionnaires beginning in 1976. Since 1980 participants were surveyed every four years regarding their frequency of food consumption. Between 1995 and 2001, cognitive function was measured in 16,010 subjects over the age of 70 years, at 2-year intervals. Women included in the present study had a mean age of 74 and mean body mass index of 26.
Findings show that increased consumption of blueberries and strawberries appear to slow cognitive decline in older women. A greater intake of anthocyanidins and total flavonoids was also associated with reduce cognitive degeneration. Researchers observed that women who had higher berry intake delayed cognitive aging by up to 2.5 years. The authors caution that while they did control for other health factors in the modeling, they cannot rule out the possibility that the preserved cognition in those who eat more berries may be also influenced by other lifestyle choices, such as exercising more.
"We provide the first epidemiologic evidence that berries may slow progression of cognitive decline in elderly women," notes Dr. Devore. "Our findings have significant public health implications as increasing berry intake is a fairly simple dietary modification to test cognition protection in older adults."
http://www.sciencedaily.com/releases/2012/04/120426110250.htm
Older Adults Who Sleep Poorly React to Stress with Increased Inflammation
March 1, 2012
Science Daily/University of Rochester Medical Center
Older adults who sleep poorly have an altered immune system response to stress that may increase risk for mental and physical health problems, according to a study led by a University of Rochester Medical Center researcher.
In the study, stress led to significantly larger increases in a marker of inflammation in poor sleepers compared to good sleepers -- a marker associated with poor health outcomes and death.
"This study offers more evidence that better sleep not only can improve overall well-being but also may help prevent poor physiological and psychological outcomes associated with inflammation," said Kathi L. Heffner, Ph.D., assistant professor of Psychiatry at the Medical Center.
Poor sleepers reported more depressive symptoms, more loneliness and more global perceived stress relative to good sleepers. Poor sleepers did not differ from good sleepers when IL-6 was measured before the tests began. Across the group, the participants showed increases in IL-6. However, poor sleepers had a significantly larger increase in IL-6 in response to the stressful tests compared to good sleepers, as much as four times larger and at a level found to increase risk for illness and death in older adults.
A further analysis of the results for the impact of loneliness, depression or perceived stress on IL-6 levels found no association. Poor sleep stood as the predictor of elevated inflammation levels.
"We found no evidence that poor sleep made them deal poorly with a stressful situation. They did just as well on the tests as the good sleepers. We did not expect that," Heffner said. "We did find that they were in a worse mood after the stressor than a good sleeper, but that change in mood did not predict the heightened inflammatory response."
As people age, a gradual decline in the immune system occurs along with an increase in inflammation. Heightened inflammation increases the risk for cardiovascular disease, diabetes and other illnesses, as well as psychiatric problems.
While relatively little is known about the pathways through which poor sleep impacts circulating levels of inflammatory proteins, the study led by Heffner provides a clinical target for preventing poor outcomes for older adults.
"There are a lot of sleep problems among older adults," Heffner said. "Older adults do not have to sleep poorly. We can intervene on sleep problems in older adulthood. Helping an elderly person become a better sleeper may reduce the risk of poor outcomes associated with inflammation."
http://www.sciencedaily.com/releases/2012/03/120301103758.htm
Eating fish reduces risk of Alzheimer's disease
December 1, 2011
Science Daily/Radiological Society of North America
People who eat baked or broiled fish on a weekly basis may be improving their brain health and reducing their risk of developing mild cognitive impairment and Alzheimer's disease, according to a new study.
"This is the first study to establish a direct relationship between fish consumption, brain structure and Alzheimer's risk," said Cyrus Raji, M.D., Ph.D., from the University of Pittsburgh Medical Center and the University of Pittsburgh School of Medicine. "The results showed that people who consumed baked or broiled fish at least one time per week had better preservation of gray matter volume on MRI in brain areas at risk for Alzheimer's disease."
Alzheimer's disease is an incurable, progressive brain disease that slowly destroys memory and cognitive skills. According to the National Institute on Aging, as many as 5.1 million Americans may have Alzheimer's disease. In MCI, memory loss is present but to a lesser extent than in Alzheimer's disease. People with MCI often go on to develop Alzheimer's disease.
The findings showed that consumption of baked or broiled fish on a weekly basis was positively associated with gray matter volumes in several areas of the brain. Greater hippocampal, posterior cingulate and orbital frontal cortex volumes in relation to fish consumption reduced the risk for five-year decline to MCI or Alzheimer's by almost five-fold.
"Consuming baked or broiled fish promotes stronger neurons in the brain's gray matter by making them larger and healthier," Dr. Raji said. "This simple lifestyle choice increases the brain's resistance to Alzheimer's disease and lowers risk for the disorder." The results also demonstrated increased levels of cognition in people who ate baked or broiled fish.
"Working memory, which allows people to focus on tasks and commit information to short-term memory, is one of the most important cognitive domains," Dr. Raji said. "Working memory is destroyed by Alzheimer's disease. We found higher levels of working memory in people who ate baked or broiled fish on a weekly basis, even when accounting for other factors, such as education, age, gender and physical activity." Eating fried fish, on the other hand, was not shown to increase brain volume or protect against cognitive decline.
http://www.sciencedaily.com/releases/2011/11/111130095257.htm
Depression and chronic stress accelerates aging
November 10, 2011
Science Daily/Umeå University
People with recurrent depressions or those exposed to chronic stress exhibits shorter telomeres in white blood cells.
The telomere is the outermost part of the chromosome. With increasing age, telomeres shorten, and studies have shown that oxidative stress and inflammation accelerates this shortening. On this basis it has been suggested that telomere length is a measure of biological aging, and telomere length has subsequently been linked to age-related diseases, unhealthy lifestyle, and longevity.
The research team shows that shorter telomere length is associated with both recurrent depression and cortisol levels indicative of exposure to chronic stress.
"The test revealed that cortisol levels indicative of chronic stress stress are associated with shorter telomeres in both depressed and healthy individuals," says Mikael Wikgren, a doctoral candidate in the research group.
The fact that depressed patients as a group have shorter telomere lengths compared to healthy individuals can be largely explained by the fact that more depressed people than healthy people have disturbed cortisol regulation, which underscores that cortisol regulation and stress play a major role in depressive disorders.
http://www.sciencedaily.com/releases/2011/11/111109093729.htm
An apple or pear a day may keep strokes away
September 16, 2011
Science Daily/American Heart Association
Eating apples and pears may help prevent stroke, according to a new study. While high consumption of fruits and vegetables is associated with lower stroke risk, a Dutch study found that eating fruit and vegetables with white edible portions was associated with a 52 percent lower stroke risk. Apples and pears were the majority of the white fruits and vegetables consumed in the study.
While previous studies have linked high consumption of fruits and vegetables with lower stroke risk, the researchers' prospective work is the first to examine associations of fruits and vegetable color groups with stroke. The color of the edible portion of fruits and vegetables reflects the presence of beneficial phytochemicals such as carotenoids and flavonoids.
Fruits and vegetables were classified in four color groups:
- · Green, including dark leafy vegetables, cabbages and lettuces
- · Orange/Yellow, which were mostly citrus fruits
- · Red/Purple, which were mostly red vegetables
- · White, of which 55 percent were apples and pears
"To prevent stroke, it may be useful to consume considerable amounts of white fruits and vegetables," said Linda M. Oude Griep, M.Sc., lead author of the study and a postdoctoral fellow in human nutrition at Wageningen Uninversity in the Netherlands. "For example, eating one apple a day is an easy way to increase white fruits and vegetable intake.
"However, other fruits and vegetable color groups may protect against other chronic diseases. Therefore, it remains of importance to consume a lot of fruits and vegetables."
Apples and pears are high in dietary fiber and a flavonoid called quercetin. In the study, other foods in the white category were bananas, cauliflower, chicory and cucumber.
http://www.sciencedaily.com/releases/2011/09/110915163523.htm
Older musicians experience less age-related decline in hearing abilities than non-musicians
September 14, 2011
Science Daily/Baycrest Centre for Geriatric Care
A study led by Canadian researchers has found the first evidence that lifelong musicians experience less age-related hearing problems than non-musicians. While hearing studies have already shown that trained musicians have highly developed auditory abilities compared to non-musicians, this is the first study to examine hearing abilities in musicians and non-musicians across the age spectrum -- from 18 to 91 years of age.
While hearing studies have already shown that trained musicians have highly developed auditory abilities compared to non-musicians, this is the first study to examine hearing abilities in musicians and non-musicians across the age spectrum -- from 18 to 91 years of age.
"What we found was that being a musician may contribute to better hearing in old age by delaying some of the age-related changes in central auditory processing. This advantage widened considerably for musicians as they got older when compared to similar-aged non-musicians," said lead investigator Benjamin Rich Zendel at Baycrest's Rotman Research Institute..
Scientists found that being a musician did not offer any advantage in the pure-tone thresholds test, across the age span. However, in the three other auditory tasks -- mistuned harmonic detection, gap detection and speech-in-noise -- musicians showed a clear advantage over non-musicians and this advantage gap widened as both groups got older. By age 70, the average musician was able to understand speech in a noisy environment as well as an average 50 year old non-musician, suggesting that lifelong musicianship can delay this age-related decline by 20 years.
Most importantly, the three assessments where musicians demonstrated an advantage all rely on auditory processing in the brain, while pure-tone thresholds do not. This suggests that lifelong musicianship mitigates age-related changes in the brains of musicians, which is probably due to musicians using their auditory systems at a high level on a regular basis. In other words, "use it or lose it."
http://www.sciencedaily.com/releases/2011/09/110913091557.htm
Memory fitness program improves memory abilities of oldest adults
August 31, 2011
Science Daily/University of California - Los Angeles Health Sciences
Who hasn't forgotten someone's name, misplaced their glasses or walked into a room and not remembered why they entered? Normal age-related memory decline affects more than half of all seniors, and those over 80 are the most vulnerable.
A new UCLA study has found that a memory fitness program offered to older adults in their senior living communities helped improve their ability to recognize and recall words, benefitting their verbal learning and retention.
Published in the September issue of the American Journal of Geriatric Psychiatry, the study also found that as a result of the program, seniors' self-perceived memory improved, an important factor in maintaining a positive outlook on life while aging. The average age of participants in the study was 81.
"It was exciting to see how much older adults participate in a memory fitness program and improve," said study author Dr. Karen Miller, an associate clinical professor at the Semel Institute for Neuroscience and Human Behavior at UCLA. "The study demonstrates that it's never too late to learn new skills to enhance one's life."
As people get older, it takes longer to learn new information and to retrieve it, including names, dates, the location of household objects, meetings, and appointments, according to the study's senior author, Dr. Gary Small, UCLA's Parlow-Solomon Professor on Aging and director of the UCLA Longevity Center.
The six-week, 12-session program differed from other cognitive training courses in that it offered not only memory-training techniques but also education about lifestyle factors that may impact memory ability and overall brain health. Participants learned stress-reduction exercises and were instructed about the importance of daily physical exercise and maintaining a healthy diet rich in antioxidants.
Among the older adults attending the classes, the researchers found marked improvement in verbal memory, as well as improvements in how they perceived their memory, compared with the controls.
"We found that the memory fitness program was readily accepted by residents in our senior living communities and that it directly benefited many of them," said John Parrish, Ph.D., executive director of the Erickson Foundation. "In fact, we are now offering the program in nearly all of our 16 communities across the nation."
"The study suggests that the memory fitness program may be a cost-effective means of addressing some of the memory-related concerns of healthy older adults," Parrish added.
http://www.sciencedaily.com/releases/2011/08/110829131310.htm
Secret to successful aging: How 'positivity effect' works in brain
July 14, 2011
Science Daily/Elsevier
Whether we choose to accept or fight it, the fact is that we will all age, but will we do so successfully? Aging successfully has been linked with the “positivity effect”, a biased tendency towards and preference for positive, emotionally gratifying experiences. New research published in Biological Psychiatry now explains how and when this effect works in the brain.
German neuroscientists studied this effect by using neuroimaging to evaluate brain engagement in young and old adults while they performed a specialized cognitive task that included supposedly irrelevant pictures of either neutral, happy, sad or fearful faces. During parts of the task when they didn't have to pay as much attention, the elderly subjects were significantly more distracted by the happy faces. When this occurred, they had increased engagement in the part of the brain that helps control emotions and this stronger signal in the brain was correlated with those who showed the greatest emotional stability.
"Integrating our findings with the assumptions of life span theories we suggest that motivational goal-shifting in healthy aging leads to a self-regulated engagement in positive emotions even when this is not required by the setting," explained author Dr. Stefanie Brassen. "In addition, our finding of a relationship between rostral anterior cingulate cortex activity and emotional stability further strengthens the hypothesis that this increased emotional control in aging enhances emotional well being."
"The lessons of healthy aging seem to be similar to those of resilience, throughout life. As recently summarized in other work by Drs. Dennis Charney and Steven Southwick, when coping with extremely stressful life challenges, it is critical to realistically appraise the situation but also to approach it with a positive attitude," noted Dr. John H. Krystal, the Editor of Biological Psychiatry.
http://www.sciencedaily.com/releases/2011/07/110714072903.htm
Keeping up your overall health may keep dementia away
July 13, 2011
Science Daily/American Academy of Neurology
Improving and maintaining health factors not traditionally associated with dementia, such as denture fit, vision and hearing, may lower a person's risk for developing dementia, according to a new study.
"Our study suggests that rather than just paying attention to already known risk factors for dementia, such as diabetes or heart disease, keeping up with your general health may help reduce the risk for dementia," said study author Kenneth Rockwood, MD, of Dalhousie University in Halifax, Nova Scotia, Canada.
The study found that each health problem increased a person's odds of developing dementia by 3.2 percent compared to people without such health problems. Older adults without health problems at baseline had an 18 percent chance to become demented in 10 years, while such risk increased to 30 percent and 40 percent in those who had 8 and 12 health problems, respectively.
http://www.sciencedaily.com/releases/2011/07/110713161824.htm
Common irregular heartbeat raises risk of dementia
August 30, 2011
Science Daily/Group Health Research Institute
The most common kind of chronically irregular heartbeat, known as atrial fibrillation, is associated with a greater risk of dementia, including Alzheimer's disease, according to a new study.
"Both atrial fibrillation and dementia increase with age," said Sascha Dublin, MD, PhD, a Group Health Research Institute assistant investigator who led the research. "Before our prospective cohort study, we knew that atrial fibrillation can cause stroke, which can lead to dementia. Now we've learned that atrial fibrillation may increase dementia risk in other, more subtle ways as well."
The results of Dr. Dublin's study suggest a relationship between atrial fibrillation and dementia beyond the connection through stroke. The people in the study had a mean age of 74 years when the study began. None had dementia or a history of stroke. At the beginning of the study, 4.3 percent had atrial fibrillation, and an additional 12.2 percent developed it during the study.
In the course of the study, 18.8 percent developed some type of dementia. People with atrial fibrillation were more likely to have other cardiovascular risk factors and disease than were those without the condition. So the researchers looked to see if atrial fibrillation increased dementia risk more than just through its association with other kinds of heart disease.
http://www.sciencedaily.com/releases/2011/08/110808104621.htm
New Evidence of Age-Related Decline in the Brain's Master Circadian Clock
July 25, 2011
Science Daily/University of California - Los Angeles
A new study of the brain's master circadian clock -- known as the suprachiasmatic nucleus, or SCN -- reveals that a key pattern of rhythmic neural activity begins to decline by middle age. The study, whose senior author is UCLA Chancellor Gene Block, may have implications for the large number of older people who have difficulty sleeping and adjusting to time changes.
"Aging has a profound effect on circadian timing," said Block, a professor of psychiatry and biobehavioral sciences and of physiological science. "It is very clear that animals' circadian systems begin to deteriorate as they age, and humans have enormous problems with the quality of their sleep as they age, difficulty adjusting to time-zone changes and difficulty performing shift-work, as well as less alertness when awake. There is a real change in the sleep-wake cycle.
"The question is, what changes in the nervous system underlie all of that? This paper suggests a primary cause of at least some of these changes is a reduction in the amplitude of the rhythmic signals from the SCN."
The SCN, located in the hypothalamus, is the central circadian clock in humans and other mammals and controls not only the timing of the sleep-wake cycle but also many other rhythmic and non-rhythmic processes in the body.
The SCN keeps the system of multiple distributed circadian oscillators in synchrony, but disruptions in the SCN lead to disrupted sleep, as well as dysfunction in memory, the cardiovascular system, and the body's immune response and metabolism.
The SCN, Block said, can be imagined as a heavy pendulum that controls many light pendulums (oscillators), with rubber bands between them.
"If the central clock weakens, it's effectively like making those rubber bands thinner and weaker," Block said. "When the SCN ages and those rubber bands become weaker, it becomes hard for the SCN to synchronize all of these other oscillators."
http://www.sciencedaily.com/releases/2011/07/110719093808.htm
Sleeping Well at 100 Years of Age: The Secrets to Healthy Longevity
May 2, 2010
Science Daily/American Academy of Sleep Medicine
A study in the May 1 issue of the journal Sleep is the first to examine sleep issues in a large sample of exceptionally old adults, including nearly 2,800 people who were 100 years of age and older.
Results show that about 65 percent of the sample reported that their sleep quality was good or very good, and the weighted average daily sleep time was about 7.5 hours including naps.
Surprisingly, the oldest adults aged 100 and above were 70 percent more likely to report good sleep quality than younger participants aged 65 to 79, after controlling for variables such as demographic characteristics, socioeconomic status and health conditions. Men were 23 percent more likely than women to report sleeping well.
Adults aged 80 and over tended to have a sleep duration that was either shorter or longer than adults aged 65 to 79, which was primarily due to deteriorating health. Controlling for health conditions showed that participants who were 100 years of age and older were less likely than the youngest elders to sleep for five or fewer hours per day, but they were almost three times more likely to sleep for 10 hour or more.
http://www.sciencedaily.com/releases/2010/05/100501013521.htm
Older People Advised That Taking an Afternoon Nap Can Lead to More Active Lives
October 26, 2010
Science Daily/University of Surrey
Experts at the University of Surrey discovered that many older people felt that they may be branded lazy for taking afternoon naps so they tried hard to avoid nodding off.
But the occasional nap can make older people more able to lead a fully active life by giving them enough energy to take part in recreational and social activities.
Susan Venn, of the Department of Sociology said: "Sleep is central to health and well-being, but as people get older, the quality of their sleep can deteriorate. They shouldn't feel guilty or think themselves lazy for having a nap."
The new research also found that as older people often have more disturbed sleep patterns at night they try to avoid taking a nap during the day only to fall asleep watching television during the early evening. As a result they may end up feeling exhausted..
Another finding was that older men and women lose sleep because of having to get up several times a night to go to the toilet, so they may cut down on drinking fluids during the day believing this will help, even though they may become dehydrated.
One interviewee, called Anne, aged 71, from Berkshire, said "My main sleep problem is waking up in the early hours of the morning and not being able to get back to sleep.
"I sometimes find on a particularly bad night that I'm awake for three or four hours. I don't want to disturb my husband by tossing and turning, and trying to get back to sleep, so I tend to get up and do the housework, watch DVDs or use the computer.
"Sleep at the moment is a disappointment I suppose, because I feel I've improved my life style by doing all the things, diet, exercise and all this, and I'd hoped that the sleep would improve more than it has."
Susan Venn, of the Department of Sociology, a researcher on the project, explained: "Many of the older people we talked to described how disturbed their sleep was, especially in terms of waking up a lot in the night.
"Anne was like many of the older people we spoke to in that being active during the day was very important to them, and if they slept badly, it impacted on how much could be achieved.
"Many older people are prescribed medications to help them sleep, but research has shown that sleeping medication may impact on the lives of older people, such as increasing the risk of falls."
The new research called "Understanding poor sleep in the community" is linked to an academic conference on sleep issues among older people, based on the SomnIA (Sleep in Ageing) project (www.somnia.surrey.ac.uk).
The research by academics at the University of Surrey, along with colleagues at other institutions, tried to find ways of improving the sleep patterns of older people.
Researchers talked to 62 older men and women who are living in their own homes about their poor sleep patterns and three key findings emerged:
- Whilst many older people do not sleep well and feel tired during the day, they often do not want to take a nap because they believe daytime sleeping is a sign of laziness.
- Older people often get up in the night to go to the toilet, sometimes even several times a night. So, counter to current advice to drink plenty of fluids during the day, they may often severely restrict how much they drink.
- Older men and women would rather not visit their doctor for problems with their sleep, largely because of a concern they will be prescribed some form of sleeping medication. Keeping busy and active is important to many older people and they are concerned that sleeping medication may take away that control. Women, more than men, tended to explore alternative treatments and remedies for poor sleep, such as over the counter remedies and herbal medicines.
http://www.sciencedaily.com/releases/2010/10/101026090834.htm
Probing the Secrets of Sharp Memory in Old Age
March 24, 2010
Science Daily/American Chemical Society
A study of the brains of people who stayed mentally sharp into their 80s and beyond challenges the notion that brain changes linked to mental decline and Alzheimer's disease are a normal, inevitable part of aging.
In a presentation given at the 239th National Meeting of the American Chemical Society (ACS) in San Fransisco March 23, Changiz Geula, Ph.D. and colleagues described their discovery of elderly people with super-sharp memory -- so-called "super-aged" individuals -- who somehow escaped formation of brain "tangles."
The tangles consist of an abnormal form of a protein called "tau" that damages and eventually kills nerve cells. Named for their snarled, knotted appearance under a microscope, tangles increase with advancing age and peak in people with Alzheimer's disease.
"This discovery is very exciting," said Geula, principal investigator of the Northwestern University Super Aging Project and a professor of neuroscience at the Cognitive Neurology and Alzheimer's Disease Center. "It is the first study of its kind and its implications are vast.
We always assumed that the accumulation of tangles is a progressive phenomenon throughout the normal aging process. Healthy people develop moderate numbers of tangles, with the most severe cases linked to Alzheimer's disease. But now we have evidence that some individuals are immune to tangle formation.
The evidence also supports the notion that the presence of tangles may influence cognitive performance. Individuals with the fewest tangles perform at superior levels. Those with more appear to be normal for their age."’
The scientists found that super-aged people appear to fall into two subgroups: Those who are almost immune to tangle formation and those that have few tangles.
"One group of super-aged seems to dodge tangle formation," Geula explained. "Their brains are virtually clean, which doesn't happen in normal-aged individuals. The other group seems to get tangles but it's less than or equal to the amount in the normal elderly. But for some reason, they seem to be protected against its effects."
http://www.sciencedaily.com/releases/2010/03/100323212139.htm
Healthy Adults May Need Less Sleep as They Age
February 2, 2010
Science Daily/American Academy of Sleep Medicine
A study in the Feb. 1 issue of the journal Sleep suggests that healthy older adults without sleep disorders can expect to have a reduced "sleep need" and to be less sleepy during the day than healthy young adults.
Results show that during a night of eight hours in bed, total sleep time decreased significantly and progressively with age. Older adults slept about 20 minutes less than middle-aged adults, who slept 23 minutes less than young adults. The number of awakenings and the amount of time spent awake after initial sleep onset increased significantly with age, and the amount of time spent in deep, slow-wave sleep decreased across age groups. Yet even with these decreases in sleep time, intensity and continuity, older adults displayed less subjective and objective daytime sleep propensity than younger adults.
Furthermore, two additional nights involving experimental disruption of slow-wave sleep led to a similar response in all age groups. Daytime sleep propensity increased, and slow-wave sleep rebounded during a night of recovery sleep. According to the authors, this suggests that the lack of increased daytime sleepiness in the presence of an age-related deterioration in sleep quality cannot be attributed to unresponsiveness to variations in homeostatic sleep pressure. Instead, healthy aging appears to be associated with reductions in the sleep duration and depth required to maintain daytime alertness.
"Our findings reaffirm the theory that it is not normal for older people to be sleepy during the daytime," said principal investigator Derk-Jan Dijk, PhD, professor of sleep and physiology at the University of Surrey in the U.K. "Whether you are young or old, if you are sleepy during the day you either don't get enough sleep or you may suffer from a sleep disorder."
The study was conducted at the Clinical Research Centre of the University of Surrey and involved 110 healthy adults without sleep disorders or sleep complaints; 44 were young (20 to 30 years), 35 were middle-aged (40 to 55 years) and 31 were older adults (66 to 83 years). After an eight-hour baseline sleep test, subjects were randomized to two nights with or without selective slow-wave sleep disruption by acoustic stimuli, followed by one recovery night. Nighttime sleep was evaluated by polysomnography, while sleep propensity was assessed using the Multiple Sleep Latency Test (MSLT) and the Karolinska Sleepiness Scale.
During the baseline night, mean objective total sleep time decreased from 433.5 minutes for young adults to 409.9 minutes for middle-aged adults and 390.4 minutes for older adults. Average minutes of slow-wave sleep decreased from 118.4 minutes for young adults to 85.3 minutes for middle-aged adults and 84.2 minutes for older adults. Mean number of minutes spent awake after initial sleep onset increased from 21 for young adults to 49.9 for middle-aged adults and 70.7 for older adults.
Objective daytime sleepiness measured by the MSLT decreased with age. When asked to lie in a comfortable position on the bed and try to fall asleep, young adults fell asleep in an average of 8.7 minutes, compared with 11.7 minutes for middle-aged adults and 14.2 minutes for older adults.
The authors noted that the cause of the age-related reductions in slow-wave sleep and sleep need still must be established. Related factors could include alterations in reproductive hormones or changes in the brain. They added that the study did not address sleep propensity during the evening hours, when it is possible that older adults may be sleepier than young adults.
According to the authors, the study also has implications for the treatment of insomnia in older adults, who may be unaware of their reduced sleep need. Therefore, sleep restriction, which leads to increased homeostatic sleep pressure, may be a successful behavioral therapy for insomnia in healthy older adults.
http://www.sciencedaily.com/releases/2010/02/100201091632.htm
Sleep Disturbances Improve After Retirement
November 2, 2009
Science Daily/American Academy of Sleep Medicine
A new study in the journal Sleep shows that retirement is followed by a sharp decrease in the prevalence of sleep disturbances. Findings suggest that this general improvement in sleep is likely to result from the removal of work-related demands and stress rather than from actual health benefits of retirement.
Results show that the odds of having disturbed sleep in the seven years after retirement were 26 percent lower (adjusted odds ratio of 0.74) than in the seven years before retiring. Sleep disturbance prevalence rates among 14,714 participants fell from 24.2 percent in the last year before retirement to 17.8 percent in the first year after retiring.
The greatest reduction in sleep disturbances was reported by participants with depression or mental fatigue prior to retirement. The postretirement improvement in sleep also was more pronounced in men, management-level workers, employees who reported high psychological job demands, and people who occasionally or consistently worked night shifts.
Results also show that there is a slowly increasing prevalence of sleep disturbances with increasing age, which can be observed both before and after retirement. From the first to the seventh year after retirement, the prevalence of sleep disturbances increased from 17.8 percent to 19.7 percent but remained significantly lower than at any time point prior to retirement.
"We believe these findings are largely applicable in situations where financial incentives not to retire are relatively weak," said Vahtera. "In countries and positions where there is no proper pension level to guarantee financial security beyond working age, however, retirement may be followed by severe stress disturbing sleep even more than before retirement."
http://www.sciencedaily.com/releases/2009/11/091101132537.htm