Aging

Greater muscle strength = better cognitive function

  • While handgrip strength has been linked to dementia risk in the elderly, a new study indicates that less impaired or fragile older adults need upper and lower body strength tests — but that these, too, are correlated with cognitive function.

A Finnish study involving 338 older adults (average age 66) has found that greater muscle strength is associated with better cognitive function.

Muscle strength was measured utilising handgrip strength, three lower body exercises such as leg extension, leg flexion and leg press and two upper body exercises such as chest press and seated row.

Handgrip strength, easy to measure, has been widely used as a measure of muscle strength, and has been associated with dementia risk among the very old. However, in this study, handgrip strength on its own showed no association with cognitive function. But both upper body strength and lower body strength were independently associated with cognitive function.

It may be that handgrip strength is only useful for older, more cognitively impaired adults.

These are gender-specific associations — muscle strength was significantly greater in men, but there was no difference in cognitive performance between men and women.

The finding is supported by previous research that found a link between walking speed and cognition in older adults, and by a 2015 study that found a striking correlation between leg power and cognition.

This 10-year British study involved 324 older female twins (average age 55). Both the degree of cognitive decline over the ten year period, and the amount of gray matter, was significantly correlated with high muscle fitness (measured by leg extension muscle power). The correlation was greater than for any other lifestyle factor tested

https://www.eurekalert.org/pub_releases/2017-06/uoef-gms062617.php

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Rapid blood pressure drops in middle age linked to dementia in old age

  • A large study indicates that an inclination to dizziness on standing up is associated with a greater risk of developing cognitive impairment and dementia decades later.

Data from over 11,500 participants in the Atherosclerosis Risk in Communities (ARIC) cohort has found evidence that orthostatic hypotension in middle age may increase the risk of cognitive impairment and dementia 20 years later.

Orthostatic hypotension is the name for the experience of dizziness or light-headedness on standing up. Previous research has suggested an association between orthostatic hypotension and cognitive decline in older adults.

In this study, participants aged 45-64 were tested for orthostatic hypotension in 1987. Those with it (703, around 6%) were 40% more likely to develop dementia in the next 20 years. They also had some 15% more cognitive decline.

Orthostatic hypotension was defined as a drop of 20 mmHg or more in systolic blood pressure or 10 mmHg or more in diastolic blood pressure, when the individual stood up after 20 minutes lying down.

More work is needed to understand the reason for the association.

https://www.eurekalert.org/pub_releases/2017-03/jhub-rbp030817.php

Rawlings, Andreea. 2017. Orthostatic Hypotension is Associated with 20-year Cognitive Decline and Incident Dementia: The Atherosclerosis Risk in Communities (ARIC) Study. Presented March 10 at the American Heart Association's EPI|LIFESTYLE 2017 Scientific Sessions in Portland, Oregon.

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Both aerobic exercise & strength training improves older brains

  • A review of research has confirmed the benefits of at least moderate exercise to fight age-related cognitive decline, with different benefits for aerobic exercise and strength training.

A review of 39 studies investigating the effect of exercise on cognition in older adults (50+) confirms that physical exercise does indeed improve cognitive function in the over 50s, regardless of their cognitive status. Aerobic exercise, resistance training, multicomponent training and tai chi, all had significant effects. However, exercise sessions needed to be at least 45  minutes and moderate intensity. Because aerobic exercise and resistance training had different effects (aerobic exercise helped overall cognition, while resistance training was particularly beneficial for executive function and working memory), it’s recommended that an exercise program include both.

https://medicalxpress.com/news/2017-04-aerobic-resistance-combo-boost-brain.html

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Higher coffee consumption linked to lower dementia risk in women

  • A large study adds to evidence that caffeine helps older women fight cognitive impairment and dementia.
  • This is supported by two animal studies showing precisely how caffeine is valuable for keeping the brain healthy.

Data from the Women's Health Initiative Memory Study, involving 6,467 postmenopausal women (65+) who reported some level of caffeine consumption, has found that those who consumed above average amounts of coffee had a lower risk of developing dementia.

Caffeine intake was estimated from a questionnaire. The median intake was 172 mg per day (an 8-ounce cup of brewed coffee contains 95mg of caffeine, 8-ounces of brewed black tea contains 47mg, so slightly less than 2 cups of coffee or less than 4 cups of tea). The women were cognitively assessed annually.

Over ten years, 388 were diagnosed with probable dementia (209) or MCI (179). Those who consumed above the median amount of caffeine had a 36% reduction in risk. The average intake in this group was 261 mg (3 cups of coffee), while the average intake for those below the median was 64 mg per day (less than one cup).

Risk factors such as hormone therapy, age, race, education, body mass index, sleep quality, depression, hypertension, prior cardiovascular disease, diabetes, smoking, and alcohol consumption, were taken into account.

The findings are consistent with other research finding a benefit for older women. It should not be assumed that the findings apply to men. It also appears that there may be a difference depending on education level. This sample had a high proportion of college-educated women.

It should also be noted that there was no clear dose-response effect — we could put more weight on the results if there was a clear relationship between amount of caffeine and benefit. Part of the problem here, however, is that it’s difficult to accurately assess the amount of caffeine, given that it’s based on self-report intake of coffee and tea, and the amount of caffeine in different beverages varies significantly.

Moreover, we do have a couple of mechanisms for caffeine to help fight age-related cognitive decline.

A recent study using rats modified to have impaired receptors for the adenosine A2A produced rats showing typical characteristics of an aging brain. In humans, too, age-related cognitive decline has been associated with over-activation of these receptors and dysfunction in glucocorticoid receptors.

The rat study shows that over-activation of the adenosine A2A receptors reduces the levels of glucocorticoid receptors in the hippocampus, which in turn impairs synaptic plasticity and cognition. In other words, it is the over-activation of the adenosine receptors that triggers a process that ends with cognitive impairment.

The point of all this is that caffeine inhibits the adenosine A2A receptors, and when the rats were given a caffeine analogue, their memory deficits returned to normal.

Another more recent study has found that caffeine increases the production of an enzyme that helps prevent tau tangles.

Building on previous research finding that an enzyme called NMNAT2 not only protects neurons from stress, but also helps prevent misfolded tau proteins (linked to Alzheimer’s, and other neurodegenerative disorders), the study identified 24 compounds (out of 1,280 tested) as having potential to increase the production of NMNAT2. One of the most effective of these was caffeine.

When caffeine was given to mice modified to produce lower levels of NMNAT2, the mice began to produce the same levels of the enzyme as normal mice.

https://www.eurekalert.org/pub_releases/2016-10/oupu-fwc100316.php

https://www.eurekalert.org/pub_releases/2016-08/ind-cai083016.php

https://www.eurekalert.org/pub_releases/2017-03/iu-cbe030717.php

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Physical activity linked to better memory for names and faces among older adults

  • A small study adds to evidence that walking improves memory in older adults, and indicates that this is particularly helpful for memory tasks the seniors find challenging.

A small study that fitted 29 young adults (18-31) and 31 older adults (55-82) with a device that recorded steps taken and the vigor and speed with which they were made, has found that those older adults with a higher step rate performed better on memory tasks than those who were more sedentary. There was no such effect seen among the younger adults.

Improved memory was found for both visual and episodic memory, and was strongest with the episodic memory task. This required recalling which name went with a person's face — an everyday task that older adults often have difficulty with.

However, the effect on visual memory had more to do with time spent sedentary than step rate. With the face-name task, both time spent sedentary and step rate were significant factors, and both factors had a greater effect than they had on visual memory.

Depression and hypertension were both adjusted for in the analysis.

There was no significant difference in executive function related to physical activity, although previous studies have found an effect. Less surprisingly, there was also no significant effect on verbal memory.

Both findings might be explained in terms of cognitive demand. The evidence suggests that the effect of physical exercise is only seen when the task is sufficiently cognitively demanding. No surprise that verbal memory (which tends to be much less affected by age) didn't meet that challenge, but interestingly, the older adults in this study were also less impaired on executive function than on visual memory. This is unusual, and reminds us that, especially with small studies, you cannot ignore the individual differences.

This general principle may also account for the lack of effect among younger adults. It is interesting to speculate whether physical activity effects would be found if the younger adults were given much more challenging tasks (either by increasing their difficulty, or selecting a group who were less capable).

Step Rate was calculated by total steps taken divided by the total minutes in light, moderate, and vigorous activities, based on the notion that this would provide an independent indicator of physical activity intensity (how briskly one is walking). Sedentary Time was the total minutes spent sedentary.

http://www.eurekalert.org/pub_releases/2015-11/bumc-slp112415.php

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[4045] Hayes SM, Alosco ML, Hayes JP, Cadden M, Peterson KM, Allsup K, Forman DE, Sperling RA, Verfaellie M. Physical Activity Is Positively Associated with Episodic Memory in Aging. Journal of the International Neuropsychological Society [Internet]. 2015 ;21(Special Issue 10):780 - 790. Available from: http://journals.cambridge.org/article_S1355617715000910

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Mentally challenging activities key to a healthy aging mind

  • A small study shows significant changes in brain activity among older adults engaged in learning a cognitively demanding skill.

A study involving 39 older adults has found that those randomly assigned to a “high-challenge” group showed improved cognitive performance and more efficient brain activity compared with those assigned to a low-challenge group, or a control group.

The high-challenge group spent at least 15 hours a week for 14 weeks learning progressively more difficult skills in digital photography, quilting, or a combination of both. The low-challenge group met to socialize and engage in activities related to subjects such as travel and cooking. The placebo group engaged in low-demand cognitive tasks such as listening to music, playing simple games, or watching classic movies.

The high-challenge group demonstrated increased neural efficiency in judging words, shown by lowered brain activity when word judgments were easy and increasing activity when they became hard. This is a pattern of response typical of young adults, and was not seen in them before the intervention, or among those in the other groups. To some extent, these changes were still seen a year later.

Moreover, there was a dose-dependent effect — meaning, those who spent more time engaging in the high-challenge activities showed the greatest brain changes.

So did those who were oldest, perhaps because their brains were most in need, perhaps because they were the most disengaged. Most likely, perhaps, because both of these were true.

The bottom line, though, is that, while all mental stimulation is good in terms of building cognitive reserve, actively learning, and really pushing yourself, is what you need to get to, or keep at, the top of your game.

http://www.eurekalert.org/pub_releases/2016-01/ip-mca011516.php

http://content.iospress.com/articles/restorative-neurology-and-neuroscience/rnn150533

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Some cognitive training helps less-educated older adults more

  • A large study in which older adults underwent various types of cognitive training has found that less-educated adults benefited more from training designed to speed processing.

Data from 2,800 participants (aged 65+) in the Advanced Cognitive Training for Independent and Vital Elderly (ACTIVE) study has revealed that one type of cognitive training benefits less-educated people more than it does the more-educated.

While the effects of reasoning and memory training did not differ as a function of how much education the individual had, those older adults with less than a complete high school education experienced a 50% greater benefit from speed of information processing training than college graduates. This advantage was maintained for three years after the end of the training.

The training involved ten 60 to 75-minute sessions over six weeks that focused on visual search and processing information in shorter and shorter times.

Both reasoning and information processing speed training resulted in improved targeted cognitive abilities for 10 years among participants, but memory training did not. Memory training focused on mnemonic strategies for remembering lists and sequences of items, text material, and main ideas and details of stories and other text-based information. Reasoning training focused on improving the ability to solve problems containing a serial pattern.

The researchers speculate that speed of information processing training might help those with less than 12 years of education, who are at greater risk of dementia, close the gap between them and those with more education.

The training modules have been translated into online games delivered by Posit Science.

Less educated study participants were slightly older, less likely to be married, more likely to be African-American, and more likely to have hypertension or diabetes as well as heart disease than the more educated older adults.

http://www.eurekalert.org/pub_releases/2016-01/iu-irs012816.php

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Omega 3 levels affect whether B vitamins can slow brain's decline

  • B vitamins can help many older adults with mild cognitive impairment, but only if they have good levels of omega-3 fatty acids.

A study involving 266 people with mild cognitive impairment (aged 70+) has found that B vitamins are more effective in slowing cognitive decline when people have higher omega 3 levels.

Participants were randomly selected to receive either a B-vitamin supplement (folic acid, vitamins B6 and B12) or a placebo pill for two years. The vitamins had little to no effect for those with low levels of omega-3 fatty acids, but were very effective for those with high baseline omega-3 levels.

Levels of DHA appeared to be more important than levels of EPA, but more research is needed to confirm that.

The finding may help to explain why research looking at the effects of B vitamins, or the effects of omega-3 oils, have produced inconsistent findings.

The study followed research showing that B vitamins can slow or prevent brain atrophy and memory decline in people with MCI, and they were most effective in those who had above average blood levels of homocysteine.

http://www.eurekalert.org/pub_releases/2016-01/uoo-ola011916.php

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Some chronic viral infections could contribute to age-related cognitive decline

  • A longitudinal study confirms findings from cross-sectional studies that certain common viral infections are factors in age-related cognitive decline.

Growing research has implicated infections as a factor in age-related cognitive decline, but these have been cross-sectional (comparing different individuals, who will have a number of other, possibly confounding, attributes). Now a large longitudinal study provides more evidence that certain chronic viral infections could contribute to subtle cognitive deterioration in apparently healthy older adults.

The study involved 1,022 older adults (65+), who had annual evaluations for five years. It revealed an association between cognitive decline and exposure to several viruses: cytomegalovirus (CMV), herpes simplex (HSV 2), and the protozoa Toxoplasma gondii.

More specifically, the IgG levels for HSV-2 were significantly associated with baseline cognitive scores, while the IgG levels for HSV-2 (genital herpes), TOX (which has been much in the news in recent years for being harbored in domestic cats, and being implicated in various neurological disorders), and CMV (a common virus which unfortunately rarely causes symptoms), but not HSV-1 (the cold sore virus), were significantly associated with greater temporal cognitive decline that varied by type of infection.

More research is obviously needed to determine more precisely what the role of different infectious agents is in cognitive decline, but the findings do point to a need for a greater emphasis on preventing and treating infections. They also add to the growing evidence that age-related cognitive decline isn't 'normal', but something that occurs when other health-related factors come into play.

http://www.eurekalert.org/pub_releases/2016-02/uops-scv020416.php

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Mediterranean diet reduces brain shrinkage in old age

  • The Mediterranean diet is the diet most associated with cognitive and health benefits in older adults.
  • A new study has found larger brain volumes among those following this sort of diet, equivalent to that of brains five years younger.
  • Much of this was associated with two components of the diet in particular: eating fish regularly, and eating less meat.

Another study adds to the growing evidence that a Mediterranean diet is good for the aging brain.

The New York study used data from 674 non-demented older adults (average age 80). It found that those who closely followed such a diet showed significantly less brain shrinkage. Specifically, total brain volume was an average 13.11 milliliters greater, with grey matter volume 5 millilitres greater, and white matter 6.4 millilitres greater.

Eating at least five of the recommended Mediterranean diet components was associated with benefits equivalent to five years of age. By far the most important of these components was regular fish and reduced meat intake — at least 3 to 5 ounces of fish weekly; no more than 3.5 ounces of meat daily.

This is consistent with a considerable amount of research indicating the benefits of fish in fighting age-related cognitive decline.

http://www.theguardian.com/lifeandstyle/2015/oct/21/mediterranean-diet-may-slow-the-ageing-process-by-five-years

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