How our brain slows down the effects of aging

September 14, 2016
Science Daily/Ruhr-Universitaet-Bochum
The older we get, the more difficult it becomes to put the world around us in order. Yet, our brain develops remarkable strategies to slow down the effects of aging.
https://images.sciencedaily.com/2016/09/160914090317_1_540x360.jpg
Older people pay more attention to the details and look more closely than younger people.
Credit: © WONG SZE FEI / Fotolia

In order to process the information that we receive every day, we build categories into which we sort everything that makes up the world around us. Neuroscientists from Ruhr-Universität Bochum (RUB) found out: the way we categorise things changes throughout our lifetimes. Their research results were now published in the journal Neuropsychologia.

The team surrounding Sabrina Schenk and Prof. Dr. Boris Suchan observed young and older people during a categorisation task. The participants of the study were asked to sort circles with varying colour combinations into one of two categories. Some of the circles were very similar to each other; others were distinctly different. To which category the circles belonged was indicated by a feedback during the test.

Brain waves and gaze direction offer insights

The scientists not only documented the test subjects' answers, they also recorded their brain waves via an EEG and used an eye tracker to trace their line of vision. The results showed that both young and older subjects had no difficulties categorising the similar looking circles -- the learning mechanism of both groups were comparable. It was only in the later stages of the experiment, when distinct looking circles where shown, that differences between the test groups became apparent. Older subjects found it more difficult to categorise these exceptions than their younger counterparts.

Brain compensates with attentiveness

"There are two main strategies which we use to categorise things. While we perceive similar looking members of a category holistically, we must specifically learn exceptions and memorise them," Schenk explains. "Older people find it harder to switch from one strategy to the other." But measurements of brain waves also showed that the elderly develop a particular selective attentiveness.

To put it simply: they pay more attention to the details and look more closely than younger people. This is also confirmed by the eye tracker, which records in which direction the participants are looking. "To a certain extent, the brain is able to slow down negative effects of aging by increasing its level of attentiveness," summarises Schenk.
 

Further studies with gamers

A computer simulation at Canada's University of Western Ontario has confirmed the results of the scientists in Bochum. In a next step the RUB team would like to test people whose attention level has been especially trained, like that of avid computer players. If these gamers do particularly well in the categorisation task, then the results may help the elderly specifically train their attentiveness.

Science Daily/SOURCE :https://www.sciencedaily.com/releases/2016/09/160914090317.htm

Prevalence of mental disorders among older people is greater than previously assumed

September 15, 2016

Science Daily/Alpen-Adria-Universität Klagenfurt | Graz | Wien
Previous studies have largely assumed that the prevalence of mental disorders declines with old age. The results of a new large-scale study with innovative diagnostic methods conducted in six European countries reveal that, considering the previous year retrospectively, approximately one third of the respondents in the age group between 65 and 85 had suffered from a mental disorder, and roughly one quarter were mentally ill at the time of the interviews.

"We started with the assumption that valid diagnostic methods for adults are less suitable for the diagnosis of mental disorders in elderly people," lead scientist Professor Sylke Andreas (Department of Psychology at the Alpen-Adria-Universität) explains. She coordinated the investigation together with Professor Martin Härter, Dr. Jana Volkert and Professor Holger Schulz (Department of Medical Psychology at the University Medical Center Hamburg-Eppendorf). When confronted with traditional diagnostic tools, older people soon struggle to remain attentive. What is more, the questions included in established diagnostic methods are often rather long and complicated, further adding to the difficulties experienced by the elderly.

As a first step, the research team, comprising scientists from Spain, Great Britain, Germany, Italy, Israel and Switzerland, developed a new diagnostic tool in the shape of a computer-based interview with simplified sentences. Subsequently, this method was used to examine 3,100 elderly people (65 to 85 years old) in Spain, Great Britain, Germany, Italy, Israel and Switzerland.

The results revealed a prevalence of mental disorders in older people that is significantly higher than had been previously assumed: At the time of the interviews, one third of the respondents had suffered from a mental disorder within the previous year (one year prevalence) and one quarter of the respondents was diagnosed with a current mental disorder. The most common disorders experienced by the respondents in the preceding twelve months were anxiety disorders (17 per cent) and depressive disorders (14 per cent).

According to Sylke Andreas, these results are cause for grave concern, particularly when considered against the background of the health services provided so far. "We need better and more reliable methods to determine whether an older person is suffering from a mental disorder. This goes hand in hand with the urgent need to establish a range of psychotherapeutic services for the elderly, which has been almost entirely absent to date."
Science Daily/SOURCE :https://www.sciencedaily.com/releases/2016/09/160915085549.htm

Do older people take fewer risks?

October 4, 2016
Science Daily/Universität Basel
Whether and how risk-taking propensity varies over a person’s life span depends in part on how risk taking is measured, research concludes. When subjects are asked how they assess their risk propensity, a clear reduction with age is the result. However, this reduction is not necessarily observed for specific risk-taking tasks. Depending on the type of task set, the propensity measured in older people can be unchanged, lower or higher. These heterogeneous results could be caused by an age-related functional change in the brain.

Cognitive and decision scientists from the University of Basel carried out research into whether we engage in more or less risk-taking behavior as we get older and into the biological foundations that influence our decision making. The researchers examined, inter alia, the influence of the measurement instruments used on the observed age-related changes in risk-taking behavior. Two studies were carried out: in the first, the researchers collected data on self-assessment and behavior in risk-taking tasks from more than 1,000 subjects aged between 18 and 90. The second study used magnetic resonance imaging to compare the brain function of younger and older adults as they solved risk-taking tasks.

Self-report and behavior do not always converge

The results of the first study, published in the journal Psychology and Aging, show that based on self-reports, risk-taking propensity decreases over the subject's life span, but can be observed both to decrease and stay the same, or even increase slightly, in a variety of risk-taking tasks. The study found that different measurement instruments sometimes result in different risk profiles.

As a potential cause for these heterogeneous results, the researchers cite the different cognitive requirements of the tasks. Demanding tasks presented a greater challenge to older people than younger people. One example of a more complex task used in both studies was the "Balloon Analogue Risk Task," which involved inflating virtual balloons, with points awarded for each pump stroke. The larger the balloon, the more points are awarded and the higher the subject's winnings at the end of the task. If the balloon is inflated too far, it bursts and all the points earned are lost. The balloons burst at various points, which are, of course, unknown to the subjects. Successful completion of the balloon task requires the extraction and integration of various pieces of information.

Older people may find it harder to cope with these demands, causing them to resort, for example, to less profitable, risk-averse behavior in the balloon task. Depending on the task structure and requirements, the risk propensity observed in older subjects may remain the same, decrease or even increase.

Neurological foundations of decision making

In order to better understand the biological foundations of these processes, in a second study the researchers compared the neural functional profiles observed in the Balloon Analogue Risk Task for groups of 26 younger and 27 older subjects. In collaboration with Chinese scientists, they identified age-related functional changes in a certain region of the brain as a potential contributing factor to the observed heterogeneity in risk tasks. As the researchers report in the journal Frontiers in Aging Neuroscience, age does not seem to substantially influence the processing of risk, reward or loss per se, but rather to affect the way they are integrated into a decision signal.

In summary, to ask whether older people take fewer risks than younger people or not is perhaps misguided. Instead, what transpires from these two studies is that risk-taking propensity and changes therein depend on the complexity of the task. The processing and integration of large quantities of information is of vital importance, in particular in terms of financial and health-related decisions. The authors therefore recommend age-appropriate structuring and communication of information in order to ensure that the preferences of older people do not result merely as an effect of the measurement.

Science Daily/SOURCE :https://www.sciencedaily.com/releases/2016/10/161004085421.htm

Brain training may help keep seniors on the road

October 10, 2016

Science Daily/Penn State University
Older adults who participate in training designed to improve cognitive ability are more likely to continue driving over the next 10 years than those who do not, according to health researchers.

"Driving cessation has huge ramifications for seniors," said Lesley A. Ross, Penn State assistant professor of human development and family studies. "It signals an end to freedom, acting as a concrete acknowledgement that you're declining."

Ross and colleagues studied the effects of three different cognitive training programs -- reasoning, memory and divided attention -- on driving cessation in older adults.

The researchers found that the participants who completed either the reasoning or divided-attention training were between 55 and 49 percent more likely to still be drivers 10 years after the study began than those who did not receive training. Randomly selected participants who received additional divided-attention training were 70 percent more likely to report still driving after 10 years. The researchers report their results in the current issue of The Gerontologist.

Over 2,000 adults aged 65 or older were randomly assigned to one of four groups -- reasoning, memory, divided attention training or no training. All of the participants were drivers at the start of the program and were in good health. The participants were evaluated seven times over the course of 10 years.

Participants randomized to one of the three types of interventions each received 10 hours of cognitive training. Following the 10 hours of training, participants were randomly selected to receive additional "booster" training.

Both the reasoning and the memory training used pencil and paper activities, while the divided-attention training used a computer program. The reasoning exercise included brain teasers and taught the participants problem-solving strategies, while the memory training involved categorization of lists of words to help with everyday life, such as a list of errands or a grocery list.

The divided-attention, or speed of processing, training used perceptual exercises where participants were shown several objects on a screen at once for a very brief period of time and then asked questions about what they had seen. This program was adaptive, becoming more difficult after the first five exercises were completed.

Ross and colleagues plan to continue to study the effect of cognitive training, including the introduction of Xbox Kinect, a computer gaming platform, into future research.

Science Daily/SOURCE :https://www.sciencedaily.com/releases/2016/10/161010143842.htm

Substance with the potential to postpone aging

October 14, 2016

Science Daily/University of Copenhagen The Faculty of Health and Medical Sciences
The coenzyme NAD+ plays a main role in aging processes. In mice and roundworm adding the substance can both extend life and postpone the onset of aging processes. New research shows that this new knowledge will eventually be able to help patients with Alzheimer's and Parkinson's disease.
https://images.sciencedaily.com/2016/10/161014152322_1_540x360.jpg
As we live longer and longer, a lot of people are occupied with their state of health and, not least, quality of life in old age. Therefore, researchers all over the world are trying to understand aging mechanisms, as this knowledge may eventually help to postpone physical aging and extend life. None of the existing explanations of physical aging are able to explain all the biological aspects of human aging.
Credit: Image courtesy of University of Copenhagen The Faculty of Health and Medical Sciences
    
As we live longer and longer, a lot of people are occupied with their state of health and, not least, quality of life in old age. Therefore, researchers all over the world are trying to understand aging mechanisms, as this knowledge may eventually help to postpone physical aging and extend life. None of the existing explanations of physical aging are able to explain all the biological aspects of human aging.

Substance Bridges Gap

Previous research has shown that a main process in aging is the capacity of the cells to keep our genes, our DNA, more or less intact. However, changes in the cells' power stations, the mitochondria, also affect aging processes. An international team of researchers from the Center for Healthy Aging at the University of Copenhagen and the National Institute of Health in the United States has shown that the substance NAD+ bridges the gap between two main aging theories -- repairs to the DNA and poor functioning mitochondria. The results have just been published in the leading journal Cell Metabolism.

'Our new study shows an age-dependent decrease in the level of NAD+, and this decrease is far greater for organisms with early aging and a lack of DNA repairs. We were surprised to see that adding NAD+ postponed both the aging processes of the cells and extended life in worms and in a mouse model', says Professor Vilhelm Bohr from the Center for Healthy Aging and the National Institute of Health.

The researchers have bred mice and roundworm with the illness Ataxia telangiectasia, A-T, for the purpose of the study. In A-T patients the part of the brain that is responsible for coordination gradually degenerates, DNA repairs are lacking, and they experience other symptoms characteristic of early aging.

Adding NAD+ Postpones Aging

'We know from previous studies that a drop in the level of NAD+ results in metabolism errors, neurodegeneration and aging, but the underlying mechanisms remain unclear to us. Our new study stresses that the substance NAD+ plays a main role both in maintaining the health of the cells' power stations and in their capacity for repairing the genes', says Professor Vilhelm Bohr.

The study also indicates that damage to the DNA can result in poor functioning mitochondria, and that this can lead to increasing neurodegeneration in A-T patients. Adding the substance NAD+ can stop the damage to the mitochondria.

Help for Patients in the Future

Even though the researchers have only examined the effect of the substance on model organisms and not administered the substance to patients, they expect to see the same effect in humans, as the cell repair mechanisms are universal for the cells of all living organisms. Understanding the universal mechanisms at cell level is key to understanding human aging and why we become more susceptible to illness as we grow older. Hopefully, this new knowledge will be able to help postpone physical aging processes and prevent illnesses such as Alzheimer's and Parkinson's disease.

Science Daily/SOURCE :https://www.sciencedaily.com/releases/2016/10/161014152322.htm

The aging brain benefits from distraction

November 15, 2016

Science Daily/Cell Press
As you age, you may find it more difficult to focus on certain tasks. But while distractions can be frustrating, they may not be as bad as we think. In a new report, researchers suggest that there may be some benefits to reduced focus, especially in people over 50. Using behavioral studies and neuroimaging evidence, the researchers discuss how being easily distracted can help adults with, for example, problem solving and learning new information.
https://images.sciencedaily.com/2016/11/161115150726_1_540x360.jpg
This figure shows the relationship between task performance and level of cognitive control.
Credit: Amer, Campbell, Hasher/Trends in Cognitive Sciences 2016

"Different types of tasks benefit from a more broad focus of attention, and this is usually seen in tasks that involve thinking creatively or using information that was previously irrelevant," says first author Tarek Amer, a psychology Ph.D. candidate at the University of Toronto and a graduate student at the Rotman Research Institute. "The literature gives us the impression that older adults are essentially doomed as their cognitive abilities decrease, when, in reality, many older adults get along just fine in their day-to-day lives, and we think that shows that aging adults don't always need to have high cognitive control."

When people have high cognitive control, they are able to maintain their focused attention and ignore distractions to get things done. But Amer and his colleagues found that people with reduced cognitive control had an easier time thinking of creative solutions to problems, and they were better at noticing patterns in the world around them. These findings also indicated that older adults could outperform their younger counterparts on certain problem-solving tasks, as they were able to broaden their attention more easily. Additionally, people didn't require high levels of cognitive control for inherent, day-to-day tasks, like walking down the street or learning new information.

In order to explore the benefits of cognitive control, many lab-based behavioral experiments require participants to complete a specific set of tasks, limiting the role of distraction. But the researchers say these experiments have shortcomings, as they don't explore situations when distractions and reduced cognitive control could be helpful, making the conclusions fairly one sided.

"Many of the tasks that we study in classic cognitive psychology are tasks that require high cognitive control, but these assigned tasks might not accurately mirror what people do in the real world because they limit distractions," says co-author Lynn Hasher, a professor of psychology at the University of Toronto and the Rotman Research Institute. "But a distraction in one setting can actually be useful information in another setting, and the more information you have, the better able you're going to be to address a current problem."

Amer and his colleagues hope to use this information to determine exactly what tasks can benefit from reduced control in order to better simulate these experiences in a lab. Although they also hope to expand the research beyond the aging population to examine how distractions can be beneficial for people with a range of cognitive impairments, for now they recognize that this understanding of cognitive control is a step closer to understanding the aging brain.

"There is a question about what really sustains performance in old age, and it's clear that working memory alone cannot provide us with the answer to that question," says Hasher. "But we think it's possible that studying reduced cognitive control can help us understand how older adults can still perform independently and successfully in their lives."

Science Daily/SOURCE :https://www.sciencedaily.com/releases/2016/11/161115150726.htm

Helping pays off: People who care for others live longer

December 22, 2016
Science Daily/Universität Basel
Older people who help and support others live longer, a new study has concluded. The results of these findings show that this kind of caregiving can have a positive effect on the mortality of the carers.
https://images.sciencedaily.com/2016/12/161222094834_1_540x360.jpg
Older people who help and support others live longer.
Credit: © aytuncoylum / Fotolia

Older people who help and support others are also doing themselves a favor. An international research team has found that grandparents who care for their grandchildren on average live longer than grandparents who do not. The researchers conducted survival analyses of over 500 people aged between 70 and 103 years, drawing on data from the Berlin Aging Study collected between 1990 and 2009.

In contrast to most previous studies on the topic, the researchers deliberately did not include grandparents who were primary or custodial caregivers. Instead, they compared grandparents who provided occasional childcare with grandparents who did not, as well as with older adults who did not have children or grandchildren but who provided care for others in their social network.

Emotional support

The results of their analyses show that this kind of caregiving can have a positive effect on the mortality of the carers. Half of the grandparents who took care of their grandchildren were still alive about ten years after the first interview in 1990. The same applied to participants who did not have grandchildren, but who supported their children -- for example, by helping with housework. In contrast, about half of those who did not help others died within five years.

The researchers were also able to show that this positive effect of caregiving on mortality was not limited to help and caregiving within the family. The data analysis showed that childless older adults who provided others with emotional support, for example, also benefited. Half of these helpers lived for another seven years, whereas non-helpers on average lived for only another four years.
 

Too intense involvement causes stress

"But helping shouldn't be misunderstood as a panacea for a longer life," says Ralph Hertwig, Director of the Center for Adaptive Rationality at the Max Planck Institute for Human Development. "A moderate level of caregiving involvement does seem to have positive effects on health. But previous studies have shown that more intense involvement causes stress, which has negative effects on physical and mental health," says Hertwig. As it is not customary for grandparents in Germany and Switzerland to take custodial care of their grandchildren, primary and custodial caregivers were not included in the analyses.

The researchers think that prosocial behavior was originally rooted in the family. "It seems plausible that the development of parents' and grandparents' prosocial behavior toward their kin left its imprint on the human body in terms of a neural and hormonal system that subsequently laid the foundation for the evolution of cooperation and altruistic behavior towards non-kin," says first author Sonja Hilbrand, doctoral student in the Department of Psychology at the University of Basel.

Science Daily/SOURCE :https://www.sciencedaily.com/releases/2016/12/161222094834.htm
 

With beetroot juice before exercise, aging brains look 'younger'

April 19, 2017

Science Daily/Wake Forest University
Drinking a beetroot juice supplement before working out makes the brain of older adults perform more efficiently, mirroring the operations of a younger brain, according to a new study.

"We knew, going in, that a number of studies had shown that exercise has positive effects on the brain," said W. Jack Rejeski, study co-author. "But what we showed in this brief training study of hypertensive older adults was that, as compared to exercise alone, adding a beet root juice supplement to exercise resulted in brain connectivity that closely resembles what you see in younger adults."

While continued work in this area is needed to replicate and extend these exciting findings, they do suggest that what we eat as we age could be critically important to the maintenance of our brain health and functional independence.

Rejeski is Thurman D. Kitchin Professor and Director of the Behavioral Medicine Laboratory in the Department of Health & Exercise Science. The study, "Beet Root Juice: An Ergogenic Aid for Exercise and the Aging Brain," was published in the peer-reviewed Journals of Gerontology: Medical Sciences. One of his former undergraduate students, Meredith Petrie, was the lead author on the paper.

This is the first experiment to test the combined effects of exercise and beetroot juice on functional brain networks in the motor cortex and secondary connections between the motor cortex and the insula, which support mobility, Rejeski said.

The study included 26 men and women age 55 and older who did not exercise, had high blood pressure, and took no more than two medications for high blood pressure. Three times a week for six weeks, they drank a beetroot juice supplement called Beet-It Sport Shot one hour before a moderately intense, 50-minute walk on a treadmill. Half the participants received Beet-It containing 560 mg of nitrate; the others received a placebo Beet-It with very little nitrate.

Beets contain a high level of dietary nitrate, which is converted to nitrite and then nitric oxide (NO) when consumed. NO increases blood flow in the body, and multiple studies have shown it can improve exercise performance in people of various ages.

"Nitric oxide is a really powerful molecule. It goes to the areas of the body which are hypoxic, or needing oxygen, and the brain is a heavy feeder of oxygen in your body," said Rejeski.

When you exercise, the brain's somatomotor cortex, which processes information from the muscles, sorts out the cues coming in from the body. Exercise should strengthen the somatomotor cortex.

So, combining beetroot juice with exercise delivers even more oxygen to the brain and creates an excellent environment for strengthening the somatomotor cortex. Post-exercise analysis showed that, although the study groups has similar levels of nitrate and nitrite in the blood before drinking the juice, the beetroot juice group had much higher levels of nitrate and nitrite than the placebo group after exercise.

Science Daily/SOURCE :https://www.sciencedaily.com/releases/2017/04/170419091619.htm

Want to stay mentally healthy in older age?

April 20, 2017

Science Daily/University of Exeter
Stimulating the brain by taking on leadership roles at work or staying on in education help people stay mentally healthy in later life, according to new research.

The large-scale investigation published in the journal PLOS Medicine and led by the University of Exeter, used data from more than 2,000 mentally fit people over the age of 65, examined the theory that experiences in early or mid life which challenge the brain make people more resilient to changes resulting from age or illness -- they have higher "cognitive reserve."

The analysis, funded by the Economic and Social Research Council (ESRC) found that people with higher levels of reserve are more likely to stay mentally fit for longer, making the brain more resilient to illnesses such as dementia.

The research team included collaborators from the universities of Bangor, Newcastle and Cambridge.

Linda Clare, Professor of Clinical Psychology of Ageing and Dementia at the University of Exeter, said: "Losing mental ability is not inevitable in later life. We know that we can all take action to increase our chances of maintaining our own mental health, through healthy living and engaging in stimulating activities. It's important that we understand how and why this occurs, so we can give people meaningful and effective measures to take control of living full and active lives into older age.

"People who engage in stimulating activity which stretches the brain, challenging it to use different strategies that exercise a variety of networks, have higher 'Cognitive reserve'. This builds a buffer in the brain, making it more resilient. It means signs of decline only become evident at a higher threshold of illness or decay than when this buffer is absent."

The research team analysed data from 2,315 mentally fit participants aged over 65 years who took part in the first wave of interviews for the Cognitive Function and Ageing Study Wales (CFAS-Wales).

They analysed whether a healthy lifestyle was associated with better performance on a mental ability test. They found that a healthy diet, more physical activity, more social and mentally stimulating activity and moderate alcohol consumption all seemed to boost cognitive performance.

Professor Bob Woods of Bangor University, who leads the CFAS Wales study, said: "We found that people with a healthier lifestyle had better scores on tests of mental ability, and this was partly accounted for by their level of cognitive reserve.

"Our results highlight the important of policies and measures that encourage older people to make changes in their diet, exercise more, and engage in more socially oriented and mentally stimulating activities."

Professor Fiona Matthews of Newcastle University, who is principal statistician on the CFAS studies, said "Many of the factors found here to be important are not only healthy for our brain, but also help at younger age avoiding heart disease."

Professor Clare is supported by the National Institute for Health Research Collaboration for Leadership in Applied Health Research and Care South West Peninsula (NIHR PenCLAHRC).

Testing our the efficacy of brain stimulation is part one aspect of the PROTECT (Platform for Research Online to investigate Genetics and Cognition in Ageing) trial, which involves Professor Clare. It has already recruited 20,000 people over the age of 50. They are taking part in Exeter-led research to establish which lifestyle measures can make a meaningful difference to keep people stay physically and mentally active in older age.

Science Daily/SOURCE : https://www.sciencedaily.com/releases/2017/04/170420113809.htm

Aerobic, resistance exercise combo can boost brain power of over 50s

Effects independent of current state of brain health, finds evidence review

April 24, 2017

Science Daily/BMJ
A combination of aerobic and resistance exercises can significantly boost the brain power of the over 50s, finds the most comprehensive review of the available evidence to date.

And the effects were evident irrespective of the current state of an individual's brain health, the analysis shows.

Physical exercise for older adults is seen as a promising means of warding off or halting a decline in brain health and cognitive abilities. Yet the evidence for its benefits is inconclusive, largely because of overly restrictive inclusion criteria in the reviews published to date, say the researchers.

In a bid to try and plug some of these gaps, they systematically reviewed 39 relevant studies published up to the end of 2016 to assess the potential impact of varying types, intensities, and durations of exercise on the brain health of the over 50s.

They included aerobic exercise; resistance training (such as weights); multi-component exercise, which contains elements of both aerobic and resistance training; tai chi; and yoga in their analysis.

They analysed the potential impact of these activities on overall brain capacity (global cognition); attention (sustained alertness, including the ability to process information rapidly); executive function (processes responsible for goal oriented behaviours); memory (storage and retrieval); and working memory (short term application of found information).

Pooled analysis of the data showed that exercise improves the brain power of the over 50s, irrespective of the current state of their brain health.

Aerobic exercise significantly enhanced cognitive abilities while resistance training had a pronounced effect on executive function, memory, and working memory.

The evidence is strong enough to recommend prescribing both types of exercise to improve brain health in the over 50s, say the researchers.

The data showed that tai chi also improved cognitive abilities, which backs the findings of previously published studies, but the analysis was based on just a few studies, caution the researchers, so will need to be confirmed in a large clinical trial.

Nevertheless, it's an important finding, they suggest, because exercises like tai chi may be suitable for people who are unable to do more challenging forms of physical activity.

And in terms of how much and how often, the data analysis showed that a session lasting between 45 and 60 minutes, of moderate to vigorous intensity, and of any frequency, was good for brain health.

The researchers point to some potential limitations of their review: their evidence was confined only to studies of supervised exercise and which had been published in English.

Nevertheless, they conclude: "The findings suggest that an exercise programme with components of both aerobic and resistance type training, of at least moderate intensity and at least 45 minutes per session, on as many days of the week as possible, is beneficial to cognitive function in adults aged over 50."

Science Daily/SOURCE :https://www.sciencedaily.com/releases/2017/04/170424215441.htm