Exercise

How physical exercise and fitness improves your brain function

Why diabetes is linked to cognitive impairment in older adults

January, 2012
  • The link between diabetes and cognitive impairment in older adults seems to be mediated by the release of molecules that increase inflammation, leading to constricted blood vessels, thus reduced blood flow, and finally loss of gray matter.

Why is diabetes associated with cognitive impairment and even dementia in older adults? New research pinpoints two molecules that trigger a cascade of events that end in poor blood flow and brain atrophy.

The study involved 147 older adults (average age 65), of whom 71 had type 2 diabetes and had been taking medication to manage it for at least five years. Brain scans showed that the diabetic patients had greater blood vessel constriction than the age- and sex-matched controls, and more brain atrophy. The reduction in brain tissue was most marked in the grey matter in the parietal and occipital lobes and cerebellum. Research has found that, at this age, while the average brain shrinks by about 1% annually, a diabetic brain might shrink by as much as 15%. Diabetics also had more white matter hyperintensities in the temporal, parietal and occipital lobes.

Behaviorally, the diabetics also had greater depression, slower walking, and executive dysfunction.

The reduced performance of blood vessels (greater vasoconstriction, blunted vasodilatation), and increased brain atrophy in the frontal, temporal, and parietal lobes, was associated with two adhesion molecules – sVCAM and sICAM. White matter hyperintensities were not associated with the adhesion molecules, inflammatory markers, or blood vessel changes.

It seems that the release of these molecules, probably brought about by chronic hyperglycemia and insulin resistance, produces chronic inflammation, which in turn brings about constricted blood vessels, reduced blood flow, and finally loss of neurons. The blood vessel constriction and the brain atrophy were also linked to higher glucose levels.

The findings suggest that these adhesion molecules provide two biomarkers of vascular health that could enable clinicians to recognize impending brain damage, that could then perhaps be prevented.

The findings also add weight to the growing evidence that diabetes management is crucial in preventing cognitive decline.

Reference: 

Source: 

Topics: 

tags: 

tags development: 

tags lifestyle: 

tags problems: 

How neighborhood status affects cognitive function in older adults

November, 2011

New research confirms the correlation between lower neighborhood socioeconomic status and lower cognitive function in older adults, and accounts for most of it through vascular health, lifestyle, and psychosocial factors.

In the last five years, three studies have linked lower neighborhood socioeconomic status to lower cognitive function in older adults. Neighborhood has also been linked to self-rated health, cardiovascular disease, and mortality. Such links between health and neighborhood may come about through exposure to pollutants or other environmental stressors, access to alcohol and cigarettes, barriers to physical activity, reduced social support, and reduced access to good health and social services.

Data from the large Women’s Health Initiative Memory Study has now been analyzed to assess whether the relationship between neighborhood socioeconomic status can be explained by various risk and protective factors for poor cognitive function.

Results confirmed that higher neighborhood socioeconomic status was associated with higher cognitive function, even after individual factors such as age, ethnicity, income, education, and marital status have been taken into account. A good deal of this was explained by vascular factors (coronary heart disease, diabetes, stroke, hypertension), health behaviors (amount of alcohol consumed, smoking, physical activity), and psychosocial factors (depression, social support). Nevertheless, the association was still (barely) significant after these factors were taken account of, suggesting some other factors may also be involved. Potential factors include cognitive activity, diet, and access to health services.

In contradiction of earlier research, the association appeared to be stronger among younger women. Consistent with other research, the association was stronger for non-White women.

Data from 7,479 older women (65-81) was included in the analysis. Cognitive function was assessed by the Modified MMSE (3MSE). Neighborhood socioeconomic status was assessed on the basis of: percentage of adults over 25 with less than a high school education, percentage of male unemployment, percentage of households below the poverty line, percentage of households receiving public assistance, percentage of female-headed households with children, and median household income. Around 87% of participants were White, 7% Black, 3% Hispanic, and 3% other. Some 92% had graduated high school, and around 70% had at least some college.

Reference: 

[2523] Shih, R. A., Ghosh-Dastidar B., Margolis K. L., Slaughter M. E., Jewell A., Bird C. E., et al.
(2011).  Neighborhood Socioeconomic Status and Cognitive Function in Women.
Am J Public Health. 101(9), 1721 - 1728.

Previous:

Lang IA, Llewellyn DJ, Langa KM, Wallace RB, Huppert FA, Melzer D. 2008. Neighborhood deprivation, individual socioeconomic status, and cognitive function in older people: analyses from the English Longitudinal Study of Ageing. J Am Geriatr Soc., 56(2), 191-198.

Sheffield KM, Peek MK. 2009. Neighborhood context and cognitive decline in older Mexican Americans: results from the Hispanic Established Populations for Epidemiologic Studies of the Elderly. Am J Epidemiol., 169(9), 1092-1101.

Wight RG, Aneshensel CS, Miller-Martinez D, et al. 2006. Urban neighborhood context, educational attainment, and cognitive function among older adults. Am J Epidemiol., 163(12), 1071-1078.

Source: 

Topics: 

tags development: 

tags lifestyle: 

tags problems: 

Diabetes & Cognition

Older news items (pre-2010) brought over from the old website

Diabetic episodes affect memory

A study involving 62 children with type 1 diabetes, of whom 33 had experienced diabetic ketoacidosis, has found those with such experience performed significantly worse on a memory test that tested their ability to recall events in association with specific details. The finding points to the importance of avoiding diabetic ketoacidosis, which is avoidable in those known to have diabetes.

[1384] Ghetti, S., Lee J. K., Sims C. E., DeMaster D. M., & Glaser N. S.
(2010).  Diabetic Ketoacidosis and Memory Dysfunction in Children with Type 1 Diabetes.
The Journal of Pediatrics. 156(1), 109 - 114.

http://www.eurekalert.org/pub_releases/2009-10/uoc--dea101909.php

Poor glucose control linked to cognitive impairment in diabetics

The ongoing Memory in Diabetes (MIND) study, involving some 3,000 type 2 diabetics 55 years and older, has found that cognitive functioning abilities drop as average blood sugar levels rise. However, there was no connection between daily blood glucose levels and cognitive performance. The study adds to growing evidence that poorer blood glucose control is strongly associated with poorer memory function, that may eventually lead to mild cognitive impairment, vascular dementia and Alzheimer's disease. It is also possible that people with impaired cognitive ability are less compliant in taking medications and controlling their diabetes. Further research will test the hypothesis that improving glucose control results in improved cognitive function.

[797] Marcovina, S. M., Launer L. J., Cukierman-Yaffe T., Gerstein H. C., Williamson J. D., Lazar R. M., et al.
(2009).  Relationship Between Baseline Glycemic Control and Cognitive Function in Individuals With Type 2 Diabetes and Other Cardiovascular Risk Factors.
Diabetes Care. 32(2), 221 - 226.

http://www.eurekalert.org/pub_releases/2009-02/wfub-hbs021109.php

Adult-onset diabetes slows mental functioning in several ways, with deficits appearing early

A comparison of 41 adults with diabetes and 424 adults in good health, aged between 53 and 90, has revealed that healthy adults performed significantly better than adults with diabetes on two of the five domains tested: executive functioning and speed of processing. There were no significant differences on tests of episodic and semantic memory, verbal fluency, reaction time and perceptual speed. The effect remained even when only the younger group (those below 70) were analyzed, indicating that the diabetes-linked cognitive deficits appear early and remain stable.

[796] Yeung, S. E., Fischer A. L., & Dixon R. A.
(2009).  Exploring effects of type 2 diabetes on cognitive functioning in older adults.
Neuropsychology. 23(1), 1 - 9.

http://www.eurekalert.org/pub_releases/2009-01/apa-ads123008.php

Blood sugar linked to normal cognitive aging

Following research showing that decreasing brain function in the area of the hippocampus called the dentate gyrus is a main contributor of normal age-related cognitive decline, an imaging study has been investigating the cause of this decreasing function by looking at measures that typically change during aging, like rising blood sugar, body mass index, cholesterol and insulin levels. The study of 240 community-based nondemented elders (average age 80 years), of whom 60 had type 2 diabetes, found that decreasing activity in the dentate gyrus only correlated with levels of blood glucose. The same association was also found in aging rhesus monkeys and in mice. The finding suggests that maintaining blood sugar levels, even in the absence of diabetes, could help maintain aspects of cognitive health. It also suggests that one reason why physical exercise benefits memory may be its effect on lowering glucose levels.

[830] Mayeux, R., Vannucci S. J., Small S. A., Wu W., Brickman A. M., Luchsinger J., et al.
(2008).  The brain in the age of old: The hippocampal formation is targeted differentially by diseases of late life.
Annals of Neurology. 64(6), 698 - 706.

http://www.eurekalert.org/pub_releases/2008-12/cumc-rac121508.php

Diabetic seniors may experience memory declines after eating high-fat food

Growing evidence links diabetes to cognitive impairment. Now a small study of 16 adults (aged 50 years and older) with type 2 diabetes compared their cognitive performance on three separate occasions, fifteen minutes after consuming different meals. One meal consisted of high fat products – a danish pastry, cheddar cheese and yogurt with added whipped cream; the second meal was only water; and the third was the high-fat meal plus high doses of vitamins C (1000 mg) and E (800 IU) tablets. Researchers found that vitamin supplementation consistently improved recall scores relative to the meal alone, while those who ate the high fat meal without vitamin supplements showed significantly more forgetfulness of words and paragraph information in immediate and time delay recall tests. Those on water meal and meal with vitamins showed similar levels in cognitive performance. The finding indicates not only that diabetics can temporarily further worsen already underlying memory problems associated with the disease by consuming unhealthy meals, but also that this can be remedied by taking high doses of antioxidant vitamins C and E with the meal, suggesting that the effect of high-fat foods is to cause oxidative stress. However, this is hardly a recommended course of action, and the real importance of this finding is that it emphasizes the need for diabetics to consume healthy foods high in antioxidants, like fruits and vegetables. Of course, this is a very small study, and further replication is needed.

[1094] Chui, M., & Greenwood C.
(2008).  Antioxidant vitamins reduce acute meal-induced memory deficits in adults with type 2 diabetes.
Nutrition Research. 28(7), 423 - 429.

http://www.eurekalert.org/pub_releases/2008-06/bcfg-swt062408.php

Stress hormone impacts memory, learning in diabetic rodents

A rodent study sheds light on why diabetes can impair cognitive function. The study found that increased levels of a stress hormone (called cortisol in humans) in diabetic rats impaired synaptic plasticity and reduced neurogenesis in the hippocampus. When levels returned to normal, the hippocampus recovered. Cortisol production is controlled by the hypothalamic-pituitary axis (HPA). People with poorly controlled diabetes often have an overactive HPA axis and excessive cortisol.

[1050] Stranahan, A. M., Arumugam T. V., Cutler R. G., Lee K., Egan J. M., & Mattson M. P.
(2008).  Diabetes impairs hippocampal function through glucocorticoid-mediated effects on new and mature neurons.
Nature Neuroscience. 11(3), 309 - 317.

http://www.eurekalert.org/pub_releases/2008-02/nioa-shi021508.php

Tight diabetes control does not impact cognitive ability in type 1 diabetes

A long-running study involving 1,441 type 1 diabetics, aged 13 to 39, has demonstrated that multiple episodes of severe hypoglycaemia, though they can cause confusion, irrational behavior, convulsions and unconsciousness, do not lead to long-term loss of cognitive ability.

[1120] The Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications(DCCT/EDIC) Study Research
(2007).  Long-Term Effect of Diabetes and Its Treatment on Cognitive Function.
N Engl J Med. 356(18), 1842 - 1852.

http://www.eurekalert.org/pub_releases/2007-05/jdc-sst050107.php

Brain function not impaired by tight diabetes control and hypoglycemia

Previous research had indicated that tight blood glucose control -- achieved by taking three or more insulin injections daily – meant type 1 diabetics were three times as likely to suffer episodes of severe hypoglycemia, raising the fear that it might lead to a long-term loss of cognitive ability. Now a follow-up study provides the reassuring news that there was no link between multiple severe hypoglycemic reactions and impaired cognitive function in people with type 1 diabetes.

Jacobson, A.M. et al. 2006. Effects of Intensive and Conventional Treatment on Cognitive Function Twelve Years after the Completion of the Diabetes Control and Complications Trial (DCCT). Abstract Number 750232, presented at the American Diabetes Association's 66th Annual Scientific Sessions held in Washington, D.C, June 9—13.

http://www.eurekalert.org/pub_releases/2006-06/jdc-lss060806.php

Fat hormone linked to learning and memory

A new study reveals why obese patients who have diabetes also may have problems with their long-term memory. Leptin — the so-called ‘fat’ hormone — doesn't cross into the brain to help regulate appetite in obese people. Leptin also acts in the hippocampus, suggesting that leptin plays a role in learning and memory. The new study supports this by demonstrating that mice navigated a maze better after they received leptin. Moreover, mice with elevated levels of amyloid-beta plaques (characteristic of Alzheimer's) were particularly sensitive to leptin.

[2400] Farr, S. A., Banks W. A., & Morley J. E.
(2006).  Effects of leptin on memory processing.
Peptides. 27(6), 1420 - 1425.

http://www.sciencedaily.com/releases/2006/06/060614090511.htm
http://www.eurekalert.org/pub_releases/2006-06/slu-alb061306.php

Age-related vision problems may be associated with cognitive impairment

Age-related macular degeneration (AMD) develops when the macula, the portion of the eye that allows people to see in detail, deteriorates. An investigation into the relationship between vision problems and cognitive impairment in 2,946 patients has been carried out by The Age-Related Eye Disease Study (AREDS) Research Group. Tests were carried out every year for four years. Those who had more severe AMD had poorer average scores on cognitive tests, an association that remained even after researchers considered other factors, including age, sex, race, education, smoking, diabetes, use of cholesterol-lowering medications and high blood pressure. Average scores also decreased as vision decreased. It’s possible that there is a biological reason for the association; it is also possible that visual impairment reduces a person’s capacity to develop and maintain relationships and to participate in stimulating activities.

Chaves, P.H.M. et al. 2006. Association Between Mild Age-Related Eye Disease Study Research Group. 2006. Cognitive Impairment in the Age-Related Eye Disease Study: AREDS Report No. 16. Archives of Ophthalmology,124, 537-543.

http://www.eurekalert.org/pub_releases/2006-04/jaaj-avp040606.php

Review supports link between lifestyle factors and cognitive function in older adults

A review of 96 papers involving 36 very large, ongoing epidemiological studies in North America and Europe looking at factors involved in maintaining cognitive and emotional health in adults as they age has concluded that controlling cardiovascular risk factors, such as reducing blood pressure, reducing weight, reducing cholesterol, treating (or preferably avoiding) diabetes, and not smoking, is important for maintaining brain health as we age. The link between hypertension and cognitive decline was the most robust across studies. They also found a consistent close correlation between physical activity and brain health. However, they caution that more research is needed before specific recommendations can be made about which types of exercise and how much exercise are beneficial. They also found protective factors most consistently reported for cognitive health included higher education level, higher socio-economic status, emotional support, better initial performance on cognitive tests, better lung capacity, more physical exercise, moderate alcohol use, and use of vitamin supplements. Psychosocial factors, such as social disengagement and depressed mood, are associated with both poorer cognitive and emotional health in late life. Increased mental activity throughout life, such as learning new things, may also benefit brain health.

Wagster M, Hendrie H, Albert M, Butters M, Gao S, Knopman DS, Launer L, Yaffe K, Cuthbert B, Edwards E. The NIH Cognitive and Emotional Health ProjectReport of the Critical Evaluation Study Committee. Alzheimer's and Dementia [Internet]. 2006 ;2(1):12 - 32. Available from: http://www.alzheimersanddementia.com/article/S1552-5260(05)00503-0/abstract?articleId=&articleTitle=&citedBy=false&medlinePmidWithoutMDLNPrefix=&overridingDateRestriction=&related=false&restrictdesc_author=&restrictDescription=&restrictName.jalz=jalz&rest

http://www.eurekalert.org/pub_releases/2006-02/aa-nss021606.php

Risk for lowered cognitive performance greater in people at high risk for stroke

A new large-scale study supports earlier suggestions that those with a high risk for stroke within 10 years are also at risk for lowered cognitive function and show a pattern of deficits similar to that seen in mild vascular cognitive impairment. It is speculated that the reason may lie in structural and functional changes in the brain that do not rise to the level of clinical detection, and this is supported by a recent brain imaging study showing that abnormal brain atrophy is related both to higher risk of stroke and poorer cognitive ability. The probability of experiencing stroke within 10 years was calculated using weighted combinations of age, systolic blood-pressure, presence of diabetes, cigarette smoking, history of cardiovascular disease, treatment for hypertension and atrial fibrillation.

[1422] Elias, M. F., Sullivan L. M., D'Agostino R. B., Elias P. K., Beiser A., Au R., et al.
(2004).  Framingham stroke risk profile and lowered cognitive performance.
Stroke; a Journal of Cerebral Circulation. 35(2), 404 - 409.

http://www.eurekalert.org/pub_releases/2004-01/ama-rfl010804.php

Age-related changes in the brain's white matter affect cognitive function

From around age 60, "white-matter lesions" appear in the brain, significantly affecting cognitive function. But without cognitive data from childhood, it is hard to know how much of the difference in cognitive abilities between elderly individuals is due to aging. A longitudinal study has been made possible by the Scottish Mental Survey of 1932, which gave 11-year-olds a validated cognitive test. Scottish researchers have tracked down healthy living men and women who took part in this Survey and retested 83 participants. Testing took place in 1999, when most participants were 78 years old.
It was found that the amount of white-matter lesions made a significant contribution to general cognitive ability differences in old age, independent of prior ability. The amount of white-matter lesions contributed 14.4% of the variance in cognitive scores; early IQ scores contributed 13.7%. The two factors were independent.
Although white-matter lesions are viewed as a normal part of aging, they are linked with other health problems, in particular to circulatory problems (including hypertension, diabetes, heart disease and cardiovascular risk factors).

[442] Deary, I. J., Leaper S. A., Murray A. D., Staff R. T., & Whalley L. J.
(2003).  Cerebral white matter abnormalities and lifetime cognitive change: a 67-year follow-up of the Scottish Mental Survey of 1932.
Psychology and Aging. 18(1), 140 - 148.

http://www.eurekalert.org/pub_releases/2003-03/apa-aci031703.php

High sugar blood levels linked to poor memory

A new study takes an important step in explaining cognitive impairment in diabetics, and suggests a possible cause for some age-related memory impairment. The study assessed non-diabetic middle-aged and elderly people. Those with impaired glucose tolerance (a pre-diabetic condition) had a smaller hippocampus and scored worse on tests for recent memory. These results were independent of age or overall cognitive performance. The brain uses glucose almost exclusively as a fuel source. The ability to get glucose from the blood is reduced in diabetes. The study raises the possibility that exercise and weight loss, which help control blood sugar levels, may be able to reverse some of the memory loss that accompanies aging.

[543] Convit, A., Wolf O. T., Tarshish C., & de Leon M. J.
(2003).  Reduced glucose tolerance is associated with poor memory performance and hippocampal atrophy among normal elderly.
Proceedings of the National Academy of Sciences of the United States of America. 100(4), 2019 - 2022.

http://www.eurekalert.org/pub_releases/2003-02/nyum-hsb013003.php

Diabetes and high blood pressure linked to decline in mental ability

A large-scale six-year study of people aged 40 to 70 years old found that people with diabetes and high blood pressure are more likely to experience cognitive decline. Diabetes was associated with greater cognitive decline for those younger than 58 as well as those older than 58, but high blood pressure was a risk factor only for the 58 and older group.

[2534] Knopman, D. S., Boland L. L., Mosley T., Howard G., Liao D., Szklo M., et al.
(2001).  Cardiovascular risk factors and cognitive decline in middle-aged adults.
Neurology. 56(1), 42 - 48.

http://www.eurekalert.org/pub_releases/2001-01/MC-Nsld-0701101.php
http://www.eurekalert.org/pub_releases/2001-01/AAoN-Dahb-0801101.php

tags lifestyle: 

tags problems: 

One cause of damage in older brains, and how exercise can help

September, 2011

Two mice studies indicate that an increase in a protein involved in immune response may be behind the reduced ability of older brains to create new neurons, and that exercise produces a protein that helps protect against damage caused by illness, injury, surgery and pollutants.

In the first mouse study, when young and old mice were conjoined, allowing blood to flow between the two, the young mice showed a decrease in neurogenesis while the old mice showed an increase. When blood plasma was then taken from old mice and injected into young mice, there was a similar decrease in neurogenesis, and impairments in memory and learning.

Analysis of the concentrations of blood proteins in the conjoined animals revealed the chemokine (a type of cytokine) whose level in the blood showed the biggest change — CCL11, or eotaxin. When this was injected into young mice, they indeed showed a decrease in neurogenesis, and this was reversed once an antibody for the chemokine was injected. Blood levels of CCL11 were found to increase with age in both mice and humans.

The chemokine was a surprise, because to date the only known role of CCL11 is that of attracting immune cells involved in allergy and asthma. It is thought that most likely it doesn’t have a direct effect on neurogenesis, but has its effect through, perhaps, triggering immune cells to produce inflammation.

Exercise is known to at least partially reverse loss of neurogenesis. Exercise has also been shown to produce chemicals that prevent inflammation. Following research showing that exercise after brain injury can help the brain repair itself, another mouse study has found that mice who exercised regularly produced interleukin-6 (a cytokine involved in immune response) in the hippocampus. When the mice were then exposed to a chemical that destroys the hippocampus, the interleukin-6 dampened the harmful inflammatory response, and prevented the loss of function that is usually observed.

One of the actions of interleukin-6 that brings about a reduction in inflammation is to inhibit tumor necrosis factor. Interestingly, I previously reported on a finding that inhibiting tumor necrosis factor in mice decreased cognitive decline that often follows surgery.

This suggests not only that exercise helps protect the brain from the damage caused by inflammation, but also that it might help protect against other damage, such as that caused by environmental toxins, injury, or post-surgical cognitive decline. The curry spice cucurmin, and green tea, are also thought to inhibit tumor necrosis factor.

Reference: 

Source: 

Topics: 

tags: 

tags development: 

tags lifestyle: 

tags memworks: 

tags problems: 

More ways exercise can help seniors fight memory loss

September, 2011

A recent study finds that cognitive decline is greater in older adults who have a high salt intake —but only if they’re not physically active. Another finds that older rats who exercise are protected from memory loss caused by bacterial infection.

A three-year study following 1,262 healthy older Canadians (aged 67-84) has found that, among those who exercised little, those who had high-salt diets showed significantly greater cognitive decline. On the bright side, sedentary older adults who had low-salt consumption did not show cognitive decline over the three years. And those who had higher levels of physical activity did not show any association between salt and cognition.

Low sodium intake is associated with reduced blood pressure and risk of heart disease, adding even more weight to the mantra: what’s good for the heart is good for the brain.

The analysis controlled for age, sex, education, waist circumference, diabetes, and dietary intakes. Salt intake was based on a food frequency questionnaire. Low sodium intake was defined as not exceeding 2,263 mg/day; mid sodium intake 3,090 mg/day; and high sodium intake 3,091 and greater mg/day. A third of the participants fell into each group. Physical activity was also measured by a self-reported questionnaire (Physical Activity Scale for the Elderly). Cognitive function was measured by the Modified MMSE.

And adding to the evidence that exercise is good for you (not that we really need any more!), a rat study has found that aging rats that ran just over half a kilometer each week were protected against long-term memory loss that can happen suddenly following bacterial infection.

Previous research found that older rats experienced memory loss following E. coli infection, but young adult rats did not. In the older animals, microglia (the brain’s immune cells) were more sensitive to infection, releasing greater quantities of inflammatory molecules called cytokines in the hippocampus. This exaggerated response brought about impairments in synaptic plasticity (the neural changes that underlie learning) and reductions in BDNF.

In this study, the rats were given unlimited access to running wheels. Although the old rats only ran an average of 0.43 miles per week (50 times less distance than the young rats), they performed better on a memory test than rats who only had access to a locked exercise wheel. Moreover, the runners performed as well on the memory test as rats that were not exposed to E. coli.

The researchers are now planning to examine the role that stress hormones may play in sensitizing microglia, and whether physical exercise slows these hormones in older rats.

Reference: 

Source: 

Topics: 

tags: 

tags development: 

tags lifestyle: 

tags memworks: 

Running faster changes brain rhythms associated with learning

September, 2011

A mouse study finds that gamma waves in the hippocampus, critically involved in learning, grow stronger as mice run faster.

I’ve always felt that better thinking was associated with my brain working ‘in a higher gear’ — literally working at a faster rhythm. So I was particularly intrigued by the findings of a recent mouse study that found that brainwaves associated with learning became stronger as the mice ran faster.

In the study, 12 male mice were implanted with microelectrodes that monitored gamma waves in the hippocampus, then trained to run back and forth on a linear track for a food reward. Gamma waves are thought to help synchronize neural activity in various cognitive functions, including attention, learning, temporal binding, and awareness.

We know that the hippocampus has specialized ‘place cells’ that record where we are and help us navigate. But to navigate the world, to create a map of where things are, we need to also know how fast we are moving. Having the same cells encode both speed and position could be problematic, so researchers set out to find how speed was being encoded. To their surprise and excitement, they found that the strength of the gamma rhythm grew substantially as the mice ran faster.

The results also confirmed recent claims that the gamma rhythm, which oscillates between 30 and 120 times a second, can be divided into slow and fast signals (20-45 Hz vs 45-120 Hz for mice, consistent with the 30-55 Hz vs 45-120 Hz bands found in rats) that originate from separate parts of the brain. The slow gamma waves in the CA1 region of the hippocampus were synchronized with slow gamma waves in CA3, while the fast gamma in CA1 were synchronized with fast gamma waves in the entorhinal cortex.

The two signals became increasingly separated with increasing speed, because the two bands were differentially affected by speed. While the slow waves increased linearly, the fast waves increased logarithmically. This differential effect could have to do with mechanisms in the source regions (CA3 and the medial entorhinal cortex, respectively), or to mechanisms in the different regions in CA1 where the inputs terminate (the waves coming from CA3 and the entorhinal cortex enter CA1 in different places).

In the hippocampus, gamma waves are known to interact with theta waves. Further analysis of the data revealed that the effects of speed on gamma rhythm only occurred within a narrow range of theta phases — but this ‘preferred’ theta phase also changed with running speed, more so for the slow gamma waves than the fast gamma waves (which is not inconsistent with the fact that slow gamma waves are more affected by running speed than fast gamma waves). Thus, while slow and fast gamma rhythms preferred similar phases of theta at low speeds, the two rhythms became increasingly phase-separated with increasing running speed.

What’s all this mean? Previous research has shown that if inputs from CA3 and the entorhinal cortex enter CA1 at the same time, the kind of long-term changes at the synapses that bring about learning are stronger and more likely in CA1. So at low speeds, synchronous inputs from CA3 and the entorhinal cortex at similar theta phases make them more effective at activating CA1 and inducing learning. But the faster you move, the more quickly you need to process information. The stronger gamma waves may help you do that. Moreover, the theta phase separation of slow and fast gamma that increases with running speed means that activity in CA3 (slow gamma source) increasingly anticipates activity in the medial entorhinal cortex (fast gamma source).

What does this mean at the practical level? Well at this point it can only be speculation that moving / exercising can affect learning and attention, but I personally am taking this on board. Most of us think better when we walk. This suggests that if you’re having trouble focusing and don’t have time for that, maybe walking down the hall or even jogging on the spot will help bring your brain cells into order!

Pushing speculation even further, I note that meditation by expert meditators has been associated with changes in gamma and theta rhythms. And in an intriguing comparison of the effect of spoken versus sung presentation on learning and remembering word lists, the group that sang showed greater coherence in both gamma and theta rhythms (in the frontal lobes, admittedly, but they weren’t looking elsewhere).

So, while we’re a long way from pinning any of this down, it may be that all of these — movement, meditation, music — can be useful in synchronizing your brain rhythms in a way that helps attention and learning. This exciting discovery will hopefully be the start of an exploration of these possibilities.

Reference: 

Source: 

Topics: 

tags: 

tags lifestyle: 

tags memworks: 

tags strategies: 

Physical exercise

Older news items (pre-2010) brought over from the old website

Exercise can aid recovery after brain radiation

A mouse study has found that exercise can prevent a decline in memory after whole-brain radiation treatment. Mice that had radiation plus access to a running wheel did as well at remembering where an escape hole in maze was as normal mice that didn't exercise. Irradiated mice that had no access to an exercise wheel eventually showed no particular preference for the section of the maze with the escape hole. The irradiated mice who didn’t exercise also showed depressive-like behavior, while those who exercised did not.

Wong-Goodrich, S.J. et al. 2009. Exercise promotes recovery from cognitive dysfunction, depressive-like behavior, and loss of hippocampal neurogenesis following whole-brain irradiation in adult mice. Presented October 20 at the annual Society for Neuroscience meeting in Chicago.

http://www.eurekalert.org/pub_releases/2009-10/dumc-eca101309.php

Older adults

Maintaining or Increasing Activity Levels May Slow Cognitive Decline in Elderly

A 7-year study of over 3000 seniors (70-79) using self-report physical activity (walking) found that 21% were consistently sedentary, 12% maintained their activity levels, 26% had declining levels, and 41% had increasing or fluctuating levels. After adjustment for age, sex, race, education, study site, diabetes, hypertension, smoking, alcohol consumption and baseline cognitive score, they found that those who were sedentary throughout the study had the lowest levels of cognitive function at the beginning and experienced the fastest rate of cognitive decline; cognitive decline also was faster in those whose physical activity levels consistently declined during the study period. However, sedentary elders who increased their physical activity improved their cognitive function, especially the ability to process complex information quickly.

Barnes, D.E. et al. 2009. The impact of changes in physical activity levels on rate of cognitive decline in a biracial cohort of non-demented elders. Presented at the Alzheimer's Association International Conference on Alzheimer's Disease July 11-16 in Vienna.

http://www.eurekalert.org/pub_releases/2009-07/aa-ah070209.php

Whether lifelong physical activity helps or hurts the aging brain depends on extent

A study of 90 post-menopausal women found that long-term strenuous activity was consistently associated with poorer performance on all eight cognitive tests, in particular tests of semantic memory, working memory, delayed verbal recall, and sustained attention. However, moderate physical activity was consistently associated with better performance on all eight of the tests, especially cognitive flexibility, working memory, and sustained attention.

Tierney, M.C. et al. 2009. Intensity of long-term physical activity and later life cognition in postmenopausal women. Presented at the Alzheimer's Association International Conference on Alzheimer's Disease July 11-16 in Vienna.

http://www.eurekalert.org/pub_releases/2009-07/aa-ah070209.php

Alzheimer's Gene May Reduce Benefits of Physical Activity for Cognitive Ability

A study of some 1800 seniors (60+) found that the association of physical activity with better cognitive function was significant only for those who didn’t carry any copies of the “Alzheimer’s gene” APOE-e4 (which is the majority of people), and was greater with age.

Obisesan, T.O., Hamilton, J. & Gillum, R.F. 2009. Aerobic-related physical activity interacting with apolipoprotein E genotypes, is associated with better cognitive function in a nationally representative sample: The Third National Health and Nutrition Examination Survey (NHANES III). Presented at the Alzheimer's Association International Conference on Alzheimer's Disease July 11-16 in Vienna.

http://www.eurekalert.org/pub_releases/2009-07/aa-ah070209.php

Physical fitness improves memory in seniors

A study of 165 older adults (59-81) has found a significant association between physical fitness and performance on certain spatial memory tests. Fitness was also strongly correlated with hippocampus size. Although rodent studies have shown that exercise increases hippocampus size and spatial memory, this is the first study to show that in humans. The findings provide more evidence for the benefits of physical exercise in preventing memory loss in older adults.

[404] Kramer, A. F., Erickson K. I., Prakash R. S., Voss M. W., Chaddock L., Hu L., et al.
(2009).  Aerobic fitness is associated with hippocampal volume in elderly humans.
Hippocampus. 19(10), 1030 - 1039.

http://www.eurekalert.org/pub_releases/2009-02/uoia-pfi022409.php

Exercise prevents stem cell drop in middle age

Following mouse research showing that the creation of new brain cells (neurogenesis) in the dentate gyrus drops off dramatically by the time mice are middle aged and that exercise can significantly slow that trend, a new mouse study has confirmed these findings and found evidence that exercise has this effect by increasing the production of BDNF.

[990] Wu, C-W., Chang Y-T., Yu L., Chen H-ing., Jen C. J., Wu S-Y., et al.
(2008).  Exercise enhances the proliferation of neural stem cells and neurite growth and survival of neuronal progenitor cells in dentate gyrus of middle-aged mice.
J Appl Physiol. 105(5), 1585 - 1594.

http://www.eurekalert.org/pub_releases/2008-11/aps-eib111708.php

Age differences in cognitive benefits of exercise and mental stimulation

A mouse study has found that while physical exercise (a running wheel) and mental stimulation (toys), singly and together, improved memory in old mice, exercise alone or exercise and stimulation improved memory in middle-aged mice but not stimulation alone, and only exercise alone benefited young mice. The results suggest that as we get old and maybe less able to exercise, cognitive stimulation can help to compensate, but exercise is central to memory reinforcement at all ages.

[751] Harburger, L. L., Nzerem C. K., & Frick K. M.
(2007).  Single enrichment variables differentially reduce age-related memory decline in female mice.
.

Behavioral Neuroscience. 121(4), 679 - 688.

Full text available at http://www.apa.org/journals/releases/bne1214679.pdf
http://www.eurekalert.org/pub_releases/2007-08/apa-eam080107.php

Fitness and childhood IQ indicators of cognitive ability in old age

Data from the Scottish Mental Survey of 1932 has revealed that physical fitness contributed more than 3% of the differences in cognitive ability in old age. The study involved 460 men and women, who were tested using the same cognitive test at age 79 that they had undergone at age 11. Physical fitness was defined by time to walk six meters, grip strength and lung function. Childhood IQ was also significantly related to lung function at age 79, perhaps because people with higher intelligence might respond more favorably to health messages about staying fit. But physical fitness was more important for cognitive ability in old age than childhood IQ. People in more professional occupations and with more education also had better fitness and higher cognitive test scores at 79.

[770] Deary, I. J., Whalley L. J., Batty D. G., & Starr J. M.
(2006).  Physical fitness and lifetime cognitive change.
Neurology. 67(7), 1195 - 1200.

http://www.eurekalert.org/pub_releases/2006-10/aaon-fac100306.php

Exercise helps sustain mental activity as we age

A review of the research on the effects of exercise on brain functioning supports the view that physical exercise helps people maintain cognitive abilities well into older age. There’s also evidence that fitness training may improve some mental processes even more than moderate activity. The review examined three types of study: epidemiological studies, human intervention studies, and animal studies. All provide support for the benefits of physical activity for the aging brain.

Kramer, A.F., Colcombe, S.J., Erickson, K. & Scalf, P. 2006. Fitness Training and the Brain: From Molecules to Minds. Presented August 11 at the 114th Annual Convention of the American Psychological Association (APA).

http://www.eurekalert.org/pub_releases/2006-08/apa-ehs080106.php

Simple Lifestyle Changes May Improve Cognitive Function

A study involving 17 people (35–69 years) with mild self-reported memory complaints but normal baseline memory performance scores, has found that 2 weeks on a program combining a brain healthy diet plan (5 small meals a day; diet rich in omega-3 fats, antioxidants and low-glycemic carbohydrates like whole grains), relaxation exercises, cardiovascular conditioning (daily walks), and mental exercise (such as crosswords and brain teasers) resulted in participants' brain metabolism decreasing 5% in working memory regions (left dorsolateral prefrontal cortex), suggesting an increased efficiency. Compared to the control group, participants also performed better in verbal fluency.

Small, G.W. et al. 2006. Effects of a 14-Day Healthy Longevity Lifestyle Program on Cognition and Brain Function. American Journal of Geriatric Psychiatry, 14, 538-545.

http://www.newsroom.ucla.edu/page.asp?RelNum=7062

Review supports link between lifestyle factors and cognitive function in older adults

A review of 96 papers involving 36 very large, ongoing epidemiological studies in North America and Europe looking at factors involved in maintaining cognitive and emotional health in adults as they age has concluded that controlling cardiovascular risk factors, such as reducing blood pressure, reducing weight, reducing cholesterol, treating (or preferably avoiding) diabetes, and not smoking, is important for maintaining brain health as we age. The link between hypertension and cognitive decline was the most robust across studies. They also found a consistent close correlation between physical activity and brain health. However, they caution that more research is needed before specific recommendations can be made about which types of exercise and how much exercise are beneficial. They also found protective factors most consistently reported for cognitive health included higher education level, higher socio-economic status, emotional support, better initial performance on cognitive tests, better lung capacity, more physical exercise, moderate alcohol use, and use of vitamin supplements. Psychosocial factors, such as social disengagement and depressed mood, are associated with both poorer cognitive and emotional health in late life. Increased mental activity throughout life, such as learning new things, may also benefit brain health.

[296] Wagster, M., Hendrie H., Albert M., Butters M., Gao S., Knopman D. S., et al.
(2006).  The NIH Cognitive and Emotional Health ProjectReport of the Critical Evaluation Study Committee.
Alzheimer's and Dementia. 2(1), 12 - 32.

http://www.eurekalert.org/pub_releases/2006-02/aa-nss021606.php

Fitness counteracts cognitive decline from hormone-replacement therapy

A study of 54 postmenopausal women (aged 58 to 80) suggests that being physically fit offsets cognitive declines attributed to long-term hormone-replacement therapy. It was found that gray matter in four regions (left and right prefrontal cortex, left parahippocampal gyrus and left subgenual cortex) was progressively reduced with longer hormone treatment, with the decline beginning after more than 10 years of treatment. Therapy shorter than 10 years was associated with increased tissue volume. Higher fitness scores were also associated with greater tissue volume. Those undergoing long-term hormone therapy had more modest declines in tissue loss if their fitness level was high. Higher fitness levels were also associated with greater prefrontal white matter regions and in the genu of the corpus callosum. The findings need to be replicated with a larger sample, but are in line with animal studies finding that estrogen and exercise have similar effects: both stimulate brain-derived neurotrophic factor.

[375] Erickson, K. I., Colcombe S. J., Elavsky S., McAuley E., Korol D. L., Scalf P. E., et al.
(2007).  Interactive effects of fitness and hormone treatment on brain health in postmenopausal women.
Neurobiology of Aging. 28(2), 179 - 185.

http://www.eurekalert.org/pub_releases/2006-01/uoia-fcc012406.php

Lifestyle changes improve seniors’ memory surprisingly quickly

A small 14-day study found that those following a memory improvement plan that included memory training, a healthy diet, physical exercise, and stress reduction, showed a 5% decrease in brain metabolism in the dorsal lateral prefrontal region of the brain (involved in working memory) suggesting they were using their brain more efficiently. This change in activity was reflected in better performance on a cognitive measure controlled by this brain region, and participants reported that they felt their memory had improved. The memory training involved doing brainteasers, crossword puzzles and memory exercises. Diet involved eating 5 small meals daily (to prevent fluctuations in blood glucose levels) that were rich in omega-3 fats, low-glycemic index carbohydrates (e.g., whole grains) and antioxidants. Physical exercise involved brisk walking and stretching, and stress reduction involved stretching and relaxation exercises.

The study was presented at the American College of Neuropsychopharmacology's Annual Meeting on December 11-15, in Hawaii.

http://www.eurekalert.org/pub_releases/2005-12/g-nsf121205.php

Lifelong mild exercise decreases cellular aging in the brain

A rat study has provided evidence that regular, light exercise (say a daily 30-minute walk or a light 1-mile run) decreases cellular aging in the brain. Those rats who had had access to an exercise wheel during their lives showed fewer byproducts of oxidative stress in their brains, and their DNA at two years resembled that of their 6 month old counterparts.

The research was presented at the Society for Neuroscience's 35th annual meeting in Washington, D.C.

http://www.eurekalert.org/pub_releases/2005-11/uof-lea110905.php

Diet, exercise, stimulating environment helps old dogs learn

A new study of beagles provides more evidence that diet and mental stimulation are important in reducing or preventing age-related cognitive decline. The study, involving 48 older beagles (aged 7 to 11), compared four combinations of behavioral enrichment (regular exercise and lots of mental stimulation) and supplementation of diet with antioxidants had on a beagle's ability to learn: regular diet and regular experience; regular diet and enriched experience; regular experience and an enriched diet; and enriched diet and an enriched experience. The study followed the beagles over two years. Those in the groups with either an enriched diet or enriched environment did better than those without either, but those who had both the enriched diet and an enriched environment did noticeably better than all the rest.

[657] Milgram, N. W., Head E., Zicker S. C., Ikeda-Douglas C. J., Murphey H., Muggenburg B., et al.
(2005).  Learning ability in aged beagle dogs is preserved by behavioral enrichment and dietary fortification: a two-year longitudinal study.
Neurobiology of Aging. 26(1), 77 - 90.

http://www.eurekalert.org/pub_releases/2005-01/uot-mtc011705.php
http://www.eurekalert.org/pub_releases/2005-01/nioa-des011805.php

Maintaining physical activity linked to less cognitive decline in older men

Longer and more intense physical activity may help people maintain their cognitive skills as they age, according to a 10-year study of 295 men, born between 1900 and 1920, from the Finland, Italy and Netherlands Elderly (FINE) Study. The study showed that over 10 years the cognitive decline in men who had reduced their daily physical activity by an hour or more was 2.6 times greater than the decline in men who maintained their activity. Men who performed their daily physical activity with a lower intensity 10 years later had a 3.6 times stronger decline than men who maintained the intensity level. Men who engaged in activities of the lowest intensity had up to 3.5 times greater decline than men who participated in activities with a higher intensity. There was no decline among those who increased the duration or intensity of their activities. Activities of medium-to-low intensity, such as walking three miles per day, was associated with less cognitive decline than the lowest-intensity activity like walking less than three miles per day.

van Gelder, B.M., Tijhuis, M.A.R., Kalmijn, S., Giampaoli, S., Nissinen, A. & Kromhout, D. 2004. Physical activity in relation to cognitive decline in elderly men: The FINE study. Neurology, 63, 2316-2321.

http://www.eurekalert.org/pub_releases/2004-12/aaon-mpa122104.php

Walking may protect elderly from dementia

A study of more than 2,200 Japanese-American men between the ages of 71 and 93 has found that elderly men who are sedentary or walk less than a quarter of a mile per day are nearly twice as likely to develop dementia and Alzheimer's disease compared to men who walk more than two miles per day. Those who walked less than a mile (and more than quarter of a mile) a day also showed a significantly greater risk of dementia than those walking more than two miles a day.

[327] Abbott, R. D., White L. R., Ross W. G., Masaki K. H., Curb D. J., & Petrovitch H.
(2004).  Walking and Dementia in Physically Capable Elderly Men.
JAMA. 292(12), 1447 - 1453.

http://www.eurekalert.org/pub_releases/2004-09/uovh-wmp091504.php

Physical activity associated with better mental functioning in older women

Since 1986, 18,766 women, aged 70 to 81 years, have been questioned on their physical activity in biennial questionnaires. The women were divided into five groups depending on their average energy expenditures. Those in the highest activity grouping had a 20% lower risk of cognitive impairment than women in the lowest. Women who walked at an easy pace for at least 1.5 hours per week had higher cognitive scores than those who walked less than forty minutes per week.

[965] Weuve, J., Kang J H., Manson JA. E., Breteler M MB., Ware J. H., & Grodstein F.
(2004).  Physical Activity, Including Walking, and Cognitive Function in Older Women.
JAMA. 292(12), 1454 - 1461.

http://www.eurekalert.org/pub_releases/2004-09/jaaj-pai091604.php

Music with exercise boosts mental performance

In the first study to look at the combined effects of music and short-term exercise on mental performance, researchers found that listening to music while exercising helped to increase scores on a verbal fluency test among cardiac rehabilitation patients. The study included 33 men and women in the final weeks of a cardiac rehabilitation program. Participants completed a verbal fluency test before and after two separate sessions of exercising on a treadmill. The workouts were scheduled a week apart and lasted about 30 minutes. Participants listened to classical music – Vivaldi's "The Four Seasons" – during one of the sessions. Participants reported feeling better emotionally and mentally after working out regardless of whether or not they listened to music. But the improvement in verbal fluency test performance after listening to music was more than double that of the non-music condition.

Emery, C.F., Hsiao, E.T., Hill, S.M. & Frid, D.J. 2003. Short-term effects of exercise and music on cognitive performance among participants in a cardiac rehabilitation program. Heart & Lung: The Journal of Acute and Critical Care, 32 (6), 368-373.

http://www.eurekalert.org/pub_releases/2004-03/osu-alm032304.php

Exercise improves attention and decision-making among seniors

An imaging study involving adults ranging in age from 58 to 78 before and after a six-month program of aerobic exercise, found specific functional differences in the middle-frontal and superior parietal regions of the brain that changed with improved aerobic fitness. Consistent with the functions of these brain regions, those who participated in the aerobic-exercise intervention significantly improved their performance on a computer-based decision-making task. Those doing toning and stretching exercises did increase activation in some areas of the brain but not in those tied to better performance. Their performance on the task was not significantly different after the exercise program. The aerobic exercise used in the study involved gradually increasing periods of walking over three months. For the final three months of the intervention program, each subject walked briskly for 45 minutes in three sessions each week.

[399] Elavsky, S., Colcombe S. J., Kramer A. F., Erickson K. I., Scalf P., McAuley E., et al.
(2004).  Cardiovascular fitness, cortical plasticity, and aging.
Proceedings of the National Academy of Sciences of the United States of America. 101(9), 3316 - 3321.

http://www.eurekalert.org/pub_releases/2004-02/uoia-esf021104.php

High sugar blood levels linked to poor memory

A new study takes an important step in explaining cognitive impairment in diabetics, and suggests a possible cause for some age-related memory impairment. The study assessed non-diabetic middle-aged and elderly people. Those with impaired glucose tolerance (a pre-diabetic condition) had a smaller hippocampus and scored worse on tests for recent memory. These results were independent of age or overall cognitive performance. The brain uses glucose almost exclusively as a fuel source. The ability to get glucose from the blood is reduced in diabetes. The study raises the possibility that exercise and weight loss, which help control blood sugar levels, may be able to reverse some of the memory loss that accompanies aging.

[543] Convit, A., Wolf O. T., Tarshish C., & de Leon M. J.
(2003).  Reduced glucose tolerance is associated with poor memory performance and hippocampal atrophy among normal elderly.
Proceedings of the National Academy of Sciences of the United States of America. 100(4), 2019 - 2022.

http://www.eurekalert.org/pub_releases/2003-02/nyum-hsb013003.php

Imaging study confirms link between exercise and cognitive function

A number of studies have suggested a link between exercise and cognitive function in older adults, but now an imaging study shows that there are actual anatomical differences in the brains of physically fit versus less fit older adults (over 55). Specifically, they found very distinct differences in the gray and white matter in the frontal, temporal, and parietal cortexes. With aging, these tissues shrink, a reduction closely matched by declines in cognitive performance. Fitness, it appears, slows that decline. A related study, published in March, suggests that women may benefit more from exercise than men.

Colcombe, S.J., Erickson, K.I., Raz, N., Webb, A.G., Cohen, N.J., McAuley, E. & Kramer, A.F. 2003. Aerobic Fitness Reduces Brain Tissue Loss in Aging Humans. Journal of Gerontology: Series A: Biological and Medical Sciences, 58, M176-M180.

http://www.eurekalert.org/pub_releases/2003-01/uoia-sif012703.php

Walking reduces cognitive decline in older women

A study that tested the cognitive abilities of 5,925 women who were 65 and older once and then again six to eight years later, found that the women who walked the least were most likely to develop cognitive decline -- 24 percent of them had significant declines in their test scores, compared to 17 percent of the most active group. The least active women walked an average of about a half mile per week, while the most active group walked an average of nearly 18 miles per week.
While any exercise appeared to be helpful, the benefit increased with every extra mile walked per week. Examples of activities that would reduce the risk of cognitive decline were: playing tennis twice a week, walking a mile per day, playing golf once a week.

The paper was presented by Kristine Yaffe at the American Academy of Neurology’s 53rd Annual Meeting in Philadelphia, May 5-11.

http://www.eurekalert.org/pub_releases/2001-05/AAoN-Wpwf-0805101.php

Aerobic exercise improves some mental processes in older adults

The team of Duke University Medical Center researchers who demonstrated in late 1999 that aerobic exercise is just as effective as medication in treating major depression in the middle-aged and elderly has now reported that the same exercise program also appears to improve the cognitive abilities of these patients. The researchers found significant improvements in the higher mental processes of memory and the so-called executive functions, which include planning, organization and the ability to mentally juggle different intellectual tasks at the same time. Attention and concentration did not appear to be affected. Because it has been theorised that a reduction in blood flow to the brain might be one of the reasons why the elderly – especially those with coronary artery disease or hypertension – might suffer some degree of cognitive decline, it is speculated that exercise might improve cognitive functioning in such patients by improving the flow of oxygen-rich blood to specific regions of the brain.

Khatri, P., Babyak, M., Herman, S., Baldewicz, T., Madden, D.J., Doraiswamy, ., Waugh, R., Krishnan, R. & Craighead, E. 2001. Effects of Exercise Training on Cognitive Functioning Among Depressed Older Men and Women. Journal of Aging and Physical Activity, 9 (1).

http://www.eurekalert.org/pub_releases/2001-01/DUMC-Aeic-1401101.php

124 previously sedentary adults, 60 to 75 years old, were randomly assigned to either aerobic (walking) or anaerobic (stretching and toning) exercise over a period of 6 months. Those who received aerobic training showed substantial improvements in performance on tasks requiring executive control (such as planning, scheduling, inhibition and working memory) compared with anaerobically trained subjects. Executive control processes are particularly affected by aging. The walking condition involved walking rapidly for 45 minutes three days a week.

Kramer, A.F., Hahn, S., Cohen, N.J., Banich, M.T., Mcauley, E., Harrison, C.R.,Chason, J., Vakil, E., Bardell, L., Boileau, R.A. & Colcombe, A. 1999. Ageing, fitness and neurocognitive function. Nature, 400, 418 - 419.

The benefits of physical exercise for cognitive and memory performance in the elderly have not been consistently demonstrated in research. This study, a longitudinal one (the Interdisciplinary Ageing (IDA) study), was designed to reduce perceived shortcomings of earlier research.

The 442 people ( 65 - 95 years old) involved in the study had had their medical data collected regularly since 1965. 46 volunteers from this group (18 women and 28 men; mean age73.2 years) participated in an eight-week resistance training program. The program involved a warm-up lasting 10 min, followed by eight resistance exercises on machines.

PParticipants displayed a significant increase in muscular strength directly after the training, and this was still significant one year later. However, there was no improvement in any subjective health ratings or psychological well-being measures, with the exception of a decrease inself-attentiveness (fewer self-centred thoughts; less anxiety about themselves and the future).

There was however a positive effect on cognitive function. Memory recall and recognition were both improved, and was still significant a year later. It is unlikely that this long-term improvement can be directly due to such a short-term physical training program, but perhaps the experience of mastering a new situation and changing established habits increased participants' motivation to seek new challenges. This openness and self-confidence could be responsible for participants staying physically, socially and mentally active and being self-reliant, all of which are prerequisites for optimal cognitive functioning.

Perrig-Chiello, P. 1998. The effects of resistance training on well-being and memory in elderly volunteers. Age and Ageing, 27

 

Dementia & MCI

Physical activity reduces MCI

A German study involving nearly 4000 older adults (55+) has found that physical activity significantly reduced the risk of developing mild cognitive impairment over a two-year period. Nearly 14% of those with no physical activity at the start of the study developed cognitive impairment, compared to 6.7% of those with moderate activity, and 5.1% of those with high activity. Moderate activity was defined as less than 3 times a week.

[248] Etgen, T., Sander D., Huntgeburth U., Poppert H., Forstl H., & Bickel H.
(2010).  Physical Activity and Incident Cognitive Impairment in Elderly Persons: The INVADE Study.
Arch Intern Med. 170(2), 186 - 193.

http://www.eurekalert.org/pub_releases/2010-01/jaaj-paa012110.php

Exercise and Mediterranean-type diet associated with lower risk for Alzheimer's

A New York study involving 1880 elderly (average age 77) is the first to investigate both exercise and diet in connection with the later development of Alzheimer’s (within a five and a half year period). Participants were asked about their activity in the two weeks prior to the interview, about the regularity and duration, as well as the quality (vigorous, moderate, light). They were also asked about their food consumption over the previous year, and their responses grouped into nine food categories, the sum of which represented a Mediterranean-type diet score. Those who were very physically active had a 33% risk reduction of Alzheimer's; those who adhered more strongly to a Mediterranean-type diet had a 40% risk reduction. Those who did both had a 60% reduction. A Mediterranean-type diet is typically characterized by high intake of fish, vegetables, legumes, fruits, cereals and monounsaturated fatty acids; relatively low intake of dairy products, meats and saturated fats; and moderate alcohol consumption.

Scarmeas, N. et al. 2009. Physical Activity, Diet, and Risk of Alzheimer Disease. Journal of the American Medical Association, 302(6), 627-637.

Full text available at http://jama.ama-assn.org/cgi/content/full/302/6/627?home
http://www.eurekalert.org/pub_releases/2009-08/cumc-eam080609.php

Moderate exercise helps mild cognitive impairment

An Australian study involving 138 older adults (50 years and over) with mild cognitive impairment, has found that those who undertook to achieve 2 ½ hours of physical activity each week (three 50 minute sessions), ranging from walking, ballroom dancing to swimming, for a six month period, continually out-scored the control group on cognitive tests during the 18 month testing period — showing that memory improvement was still evident a year after the supervised exercise period.

[1212] Lautenschlager, N. T., Cox K. L., Flicker L., Foster J. K., van Bockxmeer F. M., Xiao J., et al.
(2008).  Effect of Physical Activity on Cognitive Function in Older Adults at Risk for Alzheimer Disease: A Randomized Trial.
JAMA. 300(9), 1027 - 1037.

http://www.eurekalert.org/pub_releases/2008-09/ra-wtp090108.php
http://www.eurekalert.org/pub_releases/2008-09/uom-aow090108.php
http://www.eurekalert.org/pub_releases/2008-09/jaaj-emh082808.php

Exercise may slow brain shrinkage in early Alzheimer's

A study of 121 people age 60 and older, of whom 57 were in the early stages of Alzheimer's disease, has found that those with early Alzheimer's disease who were less physically fit (measured by cardiorespiratory fitness) had four times more brain shrinkage when compared to normal older adults than those who were more physically fit. The findings suggest the value of physical fitness in slowing down the progression of Alzheimer's disease. The association existed even after age, gender, severity of dementia, physical activity and frailty were accounted for. There was no relationship between higher fitness levels and brain changes in the group of people without dementia.

Burns, J.M. et al. 2008. Cardiorespiratory fitness and brain atrophy in early Alzheimer disease. Neurology, 71, 210-216.

http://www.eurekalert.org/pub_releases/2008-07/aaon-emp070808.php

Mental and physical exercise delays dementia

A study using genetically engineered mice has found providing the mice with an enriched environment that enhanced their mental and physical stimulation improved performance on memory tests at an early stage of Huntington's disease, when memory impairment has begun. Specific molecular changes were also observed at the synapses in the hippocampus. Those without increased mental and physical activity showed decreased levels of specific proteins that are expressed at the synapse, but those exposed to stimulation didn’t. The finding offers hope for slowing the progression of the disease, as well as other dementias.

Nithianantharajah, J., Barkus, C., Murphy, M. & Hannan, A.J. Gene–environment interactions modulating cognitive function and molecular correlates of synaptic plasticity in Huntington’s disease transgenic mice. Neurobiology of Disease, Published online ahead of print 24 November 2007

http://www.eurekalert.org/pub_releases/2008-01/ra-map012308.php

Walking and moderate exercise help prevent dementia

A four-year study involving 749 older adults has found that the top one-third of participants who exerted the most energy in moderate activities such as walking were significantly less likely to develop vascular dementia than those people in the bottom one-third of the group. Contrary to some reports, no such association was found with Alzheimer’s disease.

Ravaglia, G. et al. 2007. Physical activity and dementia risk in the elderly. Findings from a prospective Italian study. Neurology, published online ahead of print December 19

http://www.eurekalert.org/pub_releases/2007-12/aaon-wam121107.php

How mental and physical stimulation slows Alzheimer's

A new study reveals how mental and physical activity slows the cognitive decline seen in Alzheimer’s. In the study, genetically engineered mice were housed in either standard cages or ones with access to an enriched environment. After five months, the mice housed in the enriched environment had fewer Ab plaques, smaller plaque size, and reduced amyloid angiopathy compared to mice housed in standard cages. However there were no differences in the levels of soluble Ab peptide or the expression levels of its precursor protein (APP). Further investigation revealed differences suggesting that an enriched environment elicits protection via pathways that prevent Ab accumulation and enhance its clearance. The data confirm that an environment rich in mental and physical stimulation slows the progression of Alzheimer-like brain pathology.

Ambrée, O. et al. 2006. Reduction of amyloid angiopathy and A² plaque burden after enriched housing in TgCRND8 mice: involvement of multiple pathways. American Journal of Pathology, 169, 544-552.

http://www.sciencedaily.com/releases/2006/07/060724002331.php

Good physical function linked to Alzheimer's delay

A study following 2,288 older adults for six years found that those whose physical function was higher at the start of the study were three times less likely to develop dementia than were those whose physical function was lower.

Wang, L., Larson, E.B., Bowen, J.D. & van Belle, G. 2006. Performance-Based Physical Function and Future Dementia in Older People. Archives of Internal Medicine, 166, 1115-1120.

http://www.eurekalert.org/pub_releases/2006-05/ghcc-gpf051806.php

Exercise protects against Alzheimer's

A study following 1,740 seniors (aged 65 and older) over a six-year period, found that those who exercised three or more times a week had a 30 — 40% lower risk for developing dementia compared with those who exercised fewer than three times per week. Even modest amounts, such as walking 15 minutes a day, appear beneficial, and the more frail the person was, the more they benefited from regular exercise.

Larson, E.B., Wang, L., Bowen, J.D., McCormick, W.C., Teri, L., Crane, P., & Kukull, W. 2006. Exercise Is Associated with Reduced Risk for Incident Dementia among Persons 65 Years of Age and Older. Annals of Internal Medicine, 144 (2), 73-81.

http://www.eurekalert.org/pub_releases/2006-01/ghcc-eil011006.php

Exercise slows development of Alzheimer's-like brain changes in mice

Population-based studies have provided evidence that various lifestyle interventions might help slow the onset and progression of Alzheimer’s. A mouse study now provides a clue how that might work. Physical activity enhanced the learning ability of mice genetically engineered to develop amyloid plaques and decreased the level of plaque-forming beta-amyloid protein fragments in their brains. The mice were divided into mice with access to running wheels or no access. The findings are supported by another recent study that found that beta-amyloid levels decreased in the brains of another kind of transgenic mice when they were housed in groups and in environments that were enriched with running wheels, colored tunnels, and toys.

Adlard, P.A., Perreau, V.M., Pop, V. & Cotman, C.W. 2005. Voluntary Exercise Decreases Amyloid Load in a Transgenic Model of Alzheimer's Disease. Journal of Neuroscience, 25, 4217-4221.

http://www.eurekalert.org/pub_releases/2005-04/nioa-esd042605.php

Enriched environment delays onset of Alzheimer's in mice

A study of genetically engineered mice has found that an enriched environment, with more opportunities to exercise, explore and interact with others, can dramatically reduce levels of beta-amyloid peptides, hallmarks of Alzheimer's disease. The mice also showed greater activity for several genes involved in memory and learning, the growth of new nerve cells, cell survival, and the growth of new blood vessels within the brain. As with humans, mice in the enriched environment showed varying levels of activity. The most active were found to have the least beta-amyloid. Researchers suggested the reason may simply be a matter of blood flow; physical and mental activity can stimulate growth of new blood vessels and keep existing vessels open and functional.

Lazarov, O.et al. 2005. Environmental Enrichment Reduces Aβ Levels and Amyloid Deposition in Transgenic Mice. Cell, 120(5), 701-713.

http://www.eurekalert.org/pub_releases/2005-03/uocm-eed030705.php

Why diet, hormones, exercise might delay Alzheimer’s

A theory that changes in fat metabolism in the membranes of nerve cells play a role in Alzheimer's has been supported in a recent study. The study found significantly higher levels of ceramide and cholesterol in the middle frontal gyrus of Alzheimer's patients. The researchers suggest that alterations in fats (especially cholesterol and ceramide) may contribute to a "neurodegenerative cascade" that destroys neurons in Alzheimer's, and that the accumulation of ceramide and cholesterol is triggered by the oxidative stress brought on by the presence of the toxic beta amyloid peptide. The study also suggests a reason for why antioxidants such as vitamin E might delay the onset of Alzheimer's: treatment with Vitamin E reduced the levels of ceramide and cholesterol, resulting in "a significant decrease in the number of neurons killed by the beta amyloid and oxidative stress.

Cutler, R.G., Kelly, J., Storie, K., Pedersen, W.A., Tammara, A., Hatanpaa, K., Troncoso, J.C. & Mattson, M.P. 2004. Involvement of oxidative stress-induced abnormalities in ceramide and cholesterol metabolism in brain aging and Alzheimer's disease. PNAS, 101, 2070-5.

http://www.eurekalert.org/pub_releases/2004-02/aaft-nsm021004.php

Children & young adults

Aerobic fitness boosts IQ in teenage boys

Data from the 1.2 million Swedish men born between 1950 and 1976 who enlisted for mandatory military service at the age of 18 has revealed that on every measure of cognitive performance, average test scores increased according to aerobic fitness — but not muscle strength. The link was strongest for logical thinking and verbal comprehension, and the association was restricted to cardiovascular fitness. The results of the study also underline the importance of getting healthier between the ages of 15 and 18 while the brain is still changing — those who improved their cardiovascular health between 15 and 18 showed significantly greater intelligence scores than those who became less healthy over the same time period. Those who were fittest at 18 were also more likely to go to college. Although association doesn’t prove cause, the fact that the association was only with cardiovascular fitness and not strength supports a cardiovascular effect on brain function. Results from over 260,000 full-sibling pairs, over 3,000 sets of twins, and more than 1,400 sets of identical twins, also supports a causal relationship.

[819] Kuhn, H. G., Aberg M. A. I., Pedersen N. L., Toren K., Svartengren M., Backstrand B., et al.
(2009).  Cardiovascular fitness is associated with cognition in young adulthood.
Proceedings of the National Academy of Sciences. 106(49), 20906 - 20911.

http://www.physorg.com/news179415275.html
http://www.telegraph.co.uk/science/science-news/6692474/Physical-health-leads-to-mental-health.html

Vigorous exercise helps children's grades

214 sixth graders were divided into two groups — one group took a general physical education class in the first semester, then a non-physical education course in the next semester. The other group did the classes in the other order. There was no difference in performance in academic classes between those taking the physical education course and those taking the non-physical. However, students who took part in more vigorous physical activities at least three times a week (such as soccer, skateboarding) did better in academic subjects (by around 10%). It’s worth noting that PE classes only averaged 19 minutes of moderate or vigorous activity; activity outside the classroom was assessed in 30 minute blocks. Only vigorous activity impacted academic performance.

[728] Coe, D P., Pivarnik J. M., Womack C. J., Reeves M. J., & Malina R. M.
(2006).  Effect of physical education and activity levels on academic achievement in children.
Medicine and Science in Sports and Exercise. 38(8), 1515 - 1519.

http://www.sciencedaily.com/releases/2006/08/060803181914.php

Physically fit children appear to do better in classroom

Several studies in recent years have demonstrated that exercise may improve cognitive functioning in older adults. New research suggests the same may be true of children. Preliminary results from a series of studies over the past two years have found a strong relationship between academic achievement and fitness scores. One of these studies also found that fit children were faster and more accurate at a visual discrimination task than sedentary children.

The study was presented at the annual meeting of the Society for Psychophysiological Research in Santa Fe, N.M., Oct. 20-24.

http://www.eurekalert.org/pub_releases/2004-10/uoia-pfc101904.php

Lack of benefit

Whether lifelong physical activity helps or hurts the aging brain depends on extent

A study of 90 post-menopausal women found that long-term strenuous activity was consistently associated with poorer performance on all eight cognitive tests, in particular tests of semantic memory, working memory, delayed verbal recall, and sustained attention. However, moderate physical activity was consistently associated with better performance on all eight of the tests, especially cognitive flexibility, working memory, and sustained attention.

Tierney, M.C. et al. 2009. Intensity of long-term physical activity and later life cognition in postmenopausal women. Presented at the Alzheimer's Association International Conference on Alzheimer's Disease July 11-16 in Vienna.

http://www.eurekalert.org/pub_releases/2009-07/aa-ah070209.php

Alzheimer's Gene May Reduce Benefits of Physical Activity for Cognitive Ability

A study of some 1800 seniors (60+) found that the association of physical activity with better cognitive function was significant only for those who didn’t carry any copies of the “Alzheimer’s gene” APOE-e4 (which is the majority of people), and was greater with age.

Obisesan, T.O., Hamilton, J. & Gillum, R.F. 2009. Aerobic-related physical activity interacting with apolipoprotein E genotypes, is associated with better cognitive function in a nationally representative sample: The Third National Health and Nutrition Examination Survey (NHANES III). Presented at the Alzheimer's Association International Conference on Alzheimer's Disease July 11-16 in Vienna.

http://www.eurekalert.org/pub_releases/2009-07/aa-ah070209.php

Some people are 'immune' to exercise

In view of the apparent benefits of exercise for cognitive function suggested by recent research, it is worth noting that a study involving 742 people from 213 families has found that "There is astounding variation in the response to exercise. The vast majority will benefit in some way, but there will be a minority who will not benefit at all."

The results were reported at the Australian Health and Medical Research Congress in Sydney, Australia.

http://www.newscientist.com/news/news.jsp?id=ns99996735

tags lifestyle: 

tags problems: 

Moderate to intense exercise may protect the brain in old age

August, 2011
  • Moderate but not light exercise was found to help protect the brain from brain infarcts in some older adults, but not all.

Another study showing the value of exercise for preserving your mental faculties in old age. This time it has to do with the development of small brain lesions or infarcts called "silent strokes." Don’t let the words “small” and “silent” fool you — these lesions have been linked to memory problems and even dementia, as well as stroke, an increased risk of falls and impaired mobility.

The study involved 1,238 people taken from the Northern Manhattan Study, a long-running study looking at stroke and vascular problems in a diverse community. Their brains were scanned some six years after completing an exercise questionnaire, when they were an average of 70 years old. The scans found that 16% of the participants had these small brain lesions.

Those who had reported engaging in moderate to intense exercise were 40% less likely to have these infarcts compared to people who did no regular exercise. Depressingly, there was no significant difference between those who engaged in light exercise and those who didn’t exercise (which is not to say that light exercise doesn’t help in other regards! a number of studies have pointed to the value of regular brisk walking for fighting cognitive decline). This is consistent with earlier findings that only the higher levels of activity consistently protect against stroke.

The results remained the same after other vascular risk factors such as high blood pressure, high cholesterol and smoking, were accounted for. Of the participants, 43% reported no regular exercise; 36% engaged in regular light exercise (e.g., golf, walking, bowling or dancing); 21% engaged in regular moderate to intense exercise (e.g., hiking, tennis, swimming, biking, jogging or racquetball).

However, there was no association with white matter lesions, which have also been associated with an increased risk of stroke and dementia.

Moreover, this effect was not seen among those with Medicaid or no health insurance, suggesting that lower socioeconomic status (or perhaps poorer access to health care) is associated with negative factors that counteract the benefits of exercise. Previous research has found that lower SES is associated with higher cardiovascular disease regardless of access to care.

Of the participants, 65% were Hispanic, 17% non-Hispanic black, and 15% non-Hispanic white. Over half (53%) had less than high school education, and 47% were on Medicaid or had no health insurance.

Reference: 

Source: 

Topics: 

tags development: 

tags lifestyle: 

tags problems: 

Why our brains produce fewer new neurons in old age

August, 2011

New research explains why fewer new brain cells are created in the hippocampus as we get older.

It wasn’t so long ago we believed that only young brains could make neurons, that once a brain was fully matured all it could do was increase its connections. Then we found out adult brains could make new neurons too (but only in a couple of regions, albeit critical ones). Now we know that neurogenesis in the hippocampus is vital for some operations, and that the production of new neurons declines with age (leading to the idea that the reduction in neurogenesis may be one reason for age-related cognitive decline).

What we didn’t know is why this happens. A new study, using mice genetically engineered so that different classes of brain cells light up in different colors, has now revealed the life cycle of stem cells in the brain.

Adult stem cells differentiate into progenitor cells that ultimately give rise to mature neurons. It had been thought that the stem cell population remained stable, but that these stem cells gradually lose their ability to produce neurons. However, the mouse study reveals that during the mouse's life span, the number of brain stem cells decreased 100-fold. Although the rate of this decrease actually slows with age, and the output per cell (the number of progenitor cells each stem cell produces) increases, nevertheless the pool of stem cells is dramatically reduced over time.

The reason this happens (and why it wasn’t what we expected) is explained in a computational model developed from the data. It seems that stem cells in the brain differ from other stem cells. Adult stem cells in the brain wait patiently for a long time until they are activated. They then undergo a series of rapid divisions that give rise to progeny that differentiate into neurons, before ‘retiring’ to become astrocytes. What this means is that, unlike blood or gut stem cells (that renew themselves many times), brain stem cells are only used once.

This raises a somewhat worrying question: if we encourage neurogenesis (e.g. by exercise or drugs), are we simply using up stem cells prematurely? The researchers suggest the answer depends on how the neurogenesis has been induced. Parkinson's disease and traumatic brain injury, for example, activate stem cells directly, and so may reduce the stem cell population. However, interventions such as exercise stimulate the progenitor cells, not the stem cells themselves.

Reference: 

Source: 

Topics: 

tags development: 

tags lifestyle: 

tags memworks: 

tags problems: 

Some cancer survivors can't shake foggy brain

July, 2011

For a minority of cancer survivors, cognitive problems will persist for years. Help with sleeping problems, and t’ai chi for stress release, may be beneficial.

A recent study of cancer survivors has found that many survivors still suffer moderate to severe problems with pain, fatigue, sleep, memory and concentration three to five years after treatment has ended.

The study included 248 survivors of breast, colorectal, lung and prostate cancer. The survivors were primarily female and white, and most were more than five years post-diagnosis. Cognitive difficulties were reported by 13%. The other most common symptoms were fatigue (16%), disturbed sleep (15%), and pain (13%). Two assessments were made, one month apart. The similar results indicate these symptoms tend to be chronic.

The researchers pointed to the need for education programs to help survivors transition from treatment to life as a cancer survivor, and the need for clinicians and researchers to develop better ways to address sleep problems, fatigue and lasting difficulties with memory and concentration.

One activity that could be part of a post-treatment program is t'ai chi.  A recent pilot study involving 23 women with a history of chemotherapy has found better cognitive and physical functioning after 10 weeks participating in a 60-minute t’ai chi class twice a week. Before and after the intervention, participants completed tests of memory, executive functioning, language, and attention, as well as tests of balance and self-report questionnaires of neuropsychological complaints, stress and mood, and fatigue.

However, though I’m a big fan of t’ai chi, I do have to note that without a control group, allowing the passing of time and the effects of any sort of group activity to be taken into account, it’s hard to draw any real conclusions from this.

Still, some support for this finding can be found in a recent meta-analysis of research investigating the benefits of t'ai chi for any improvement of medical conditions or clinical symptoms. This review found that the only clear evidence is in relation to fall prevention and improving psychological health. So, only middling support for t'ai chi, but the affirmation of its benefit for psychological health does support the potential value of this meditational practice for cancer survivors.

Reference: 

The findings of the first study were presented June 4 at the 2011 American Society of Clinical Oncology Annual Meeting in Chicago.

[2320] Reid-Arndt, S. A., Matsuda S., & Cox C. R.
(Submitted).  Tai Chi effects on neuropsychological, emotional, and physical functioning following cancer treatment: A pilot study.
Complementary Therapies in Clinical Practice. In Press, Corrected Proof,

[2319] Lee, M S., & Ernst E.
(2011).  Systematic reviews of t'ai chi: an overview.
British Journal of Sports Medicine.

Source: 

Topics: 

tags: 

tags lifestyle: 

tags memworks: 

tags problems: 

Pages

Subscribe to RSS - Exercise
Error | About memory

Error

The website encountered an unexpected error. Please try again later.