Exercise improves memory, boosts blood flow to brain

Study: 1-year workout program shows benefits for older people at risk of dementia

May 20, 2020

Science Daily/UT Southwestern Medical Center

Scientists have collected plenty of evidence linking exercise to brain health, with some research suggesting fitness may even improve memory. But what happens during exercise to trigger these benefits? New UT Southwestern research that mapped brain changes after one year of aerobic workouts has uncovered a potentially critical process: Exercise boosts blood flow into two key regions of the brain associated with memory. Notably, the study showed this blood flow can help even older people with memory issues improve cognition, a finding that scientists say could guide future Alzheimer's disease research.

"Perhaps we can one day develop a drug or procedure that safely targets blood flow into these brain regions," says Binu Thomas, Ph.D., a UT Southwestern senior research scientist in neuroimaging. "But we're just getting started with exploring the right combination of strategies to help prevent or delay symptoms of Alzheimer's disease. There's much more to understand about the brain and aging."

Blood flow and memory

The study, published in the Journal of Alzheimer's Disease, documented changes in long-term memory and cerebral blood flow in 30 participants, each of them 60 or older with memory problems. Half of them underwent 12 months of aerobic exercise training; the rest did only stretching.

The exercise group showed 47 percent improvement in memory scores after one year compared with minimal change in the stretch participants. Brain imaging of the exercise group, taken while they were at rest at the beginning and end of the study, showed increased blood flow into the anterior cingulate cortex and the hippocampus -- neural regions that play important roles in memory function.

Other studies have documented benefits for cognitively normal adults on an exercise program, including previous research from Thomas that showed aging athletes have better blood flow into the cortex than sedentary older adults. But the new research is significant because it plots improvement over a longer period in adults at high risk to develop Alzheimer's disease.

"We've shown that even when your memory starts to fade, you can still do something about it by adding aerobic exercise to your lifestyle," Thomas says.

Mounting evidence

The search for dementia interventions is becoming increasingly pressing: More than 5 million Americans have Alzheimer's disease, and the number is expected to triple by 2050.

Recent research has helped scientists gain a greater understanding of the molecular genesis of the disease, including a 2018 discovery from UT Southwestern's Peter O'Donnell Jr. Brain Institute that is guiding efforts to detect the condition before symptoms arise. Yet the billions of dollars spent on researching how to prevent or slow dementia have yielded no proven treatments that would make an early diagnosis actionable for patients.

UT Southwestern scientists are among many teams across the world trying to determine if exercise may be the first such intervention. Evidence is mounting that it could at least play a small role in delaying or reducing the risk of Alzheimer's disease.

For example, a 2018 study showed that people with lower fitness levels experienced faster deterioration of vital nerve fibers in the brain called white matter. A study published last year showed exercise correlated with slower deterioration of the hippocampus.

Regarding the importance of blood flow, Thomas says it may someday be used in combination with other strategies to preserve brain function in people with mild cognitive impairment.

"Cerebral blood flow is a part of the puzzle, and we need to continue piecing it together," Thomas says. "But we've seen enough data to know that starting a fitness program can have lifelong benefits for our brains as well as our hearts."

https://www.sciencedaily.com/releases/2020/05/200520084123.htm

Daily avocado consumption improves attention in persons with overweight, obesity

March 10, 2020

Science Daily/University of Illinois at Urbana-Champaign, News Bureau

A diet including daily avocado consumption improves the ability to focus attention in adults whose measurements of height and weight are categorized as overweight or obese, a new randomized control trial found.

Researchers at the University of Illinois at Urbana-Champaign conducted the 12-week study, published in the International Journal of Psychophysiology.

"Previous work has shown that individuals with overweight and obesity are at higher risk for cognitive decline and dementia in older age," said kinesiology and community health professor Naiman Khan, who led the study. "We are interested in whether dietary approaches may have benefits for cognitive health, especially in midlife."

The Hass Avocado Board and the U.S. Department of Agriculture's National Institute of Food and Agriculture supported this work.

Avocados are high in lutein, a dietary component associated with cognitive benefits. Though avocado consumption's benefits have been studied in older adults and children, no randomized controlled trials had studied its cognitive effects on adults with overweight or obesity, despite 70% of the American adult population falling into that category, said graduate student Caitlyn Edwards, the first author of the study.

In the new study, the researchers provided 12 weeks of daily meals to 84 adults with overweight or obesity. The meals were identical in calories and macronutrients, but one group's meals included a fresh avocado every day, while the control group had no avocado in their meals.

At the beginning and end of the study, the participants completed three cognitive tests to measure attention and inhibition. In addition, the researchers measured lutein levels in the participants' serum and in their retinas, which is associated with the lutein concentration in the brain.

They found that the participants whose diets included avocados improved their performance on one of the cognitive tests, called the Flanker task, which measures attentional inhibition -- the ability to maintain focus on the task at hand even in the face of distraction. However, there was no difference in the other two cognitive tests.

"It could be that nutrients in avocados have a specific action in the brain that supports the ability to do this task in particular, or they could be more beneficial for certain cognitive abilities over others," Khan said. "It's also possible that with a longer study or different tests, we could see other effects. Other studies have found broader effects in other populations, so it is interesting to see a more specific benefit for this population."

Another unexpected finding was that, while the participants who ate avocados had higher levels of lutein at the end of the study, the changes in lutein levels were not correlated with their cognitive changes.

"Avocados also are high in fiber and monounsaturated fats. It is possible that these other nutrients may have played a role in the cognitive effects we saw, but we focused on the lutein in our analyses," Edwards said. "Future analyses may focus on other nutrients found in avocados, or avocado consumption's impact on other measures such as weight status, inflammation and potential changes in the microbiome."

Although this study focused on avocados, other dietary sources of lutein, fiber and unsaturated fats -- such as green leafy vegetables or eggs -- also have potential cognitive and health benefits. The researchers say their study shows that small dietary changes, such as eating avocados, can have measurable impacts on cognitive performance, even when other health behaviors remain the same.

"Our mission is to give people options. There are multiple ways people can eat to optimize brain health," Khan said. "What we're learning is that avocados may be one of those fruits that may be neuroprotective in certain ways. This work provides some evidence behind one option people have from a plethora of healthful foods that we can consume."

https://www.sciencedaily.com/releases/2020/03/200310124711.htm

Keep exercising: New study finds it's good for your brain's gray matter

January 2, 2020

Science Daily/Mayo Clinic

A study provides new evidence of an association between cardiorespiratory fitness and brain health, particularly in gray matter and total brain volume -- regions of the brain involved with cognitive decline and aging.

Cardiorespiratory exercise -- walking briskly, running, biking and just about any other exercise that gets your heart pumping -- is good for your body, but can it also slow cognitive changes in your brain?

A study in Mayo Clinic Proceedings from the German Center for Neurodegenerative Diseases provides new evidence of an association between cardiorespiratory fitness and brain health, particularly in gray matter and total brain volume -- regions of the brain involved with cognitive decline and aging.

Brain tissue is made up of gray matter, or cell bodies, and filaments, called white matter, that extend from the cells. The volume of gray matter appears to correlate with various skills and cognitive abilities. The researchers found that increases in peak oxygen uptake were strongly associated with increased gray matter volume.

The study involved 2,013 adults from two independent cohorts in northeastern Germany. Participants were examined in phases from 1997 through 2012. Cardiorespiratory fitness was measured using peak oxygen uptake and other standards while participants used an exercise bike. MRI brain data also were analyzed.

The results suggest cardiorespiratory exercise may contribute to improved brain health and decelerate a decline in gray matter. An editorial by three Mayo Clinic experts that accompanies the Mayo Clinic Proceedings study says the results are "encouraging, intriguing and contribute to the growing literature relating to exercise and brain health."

Ronald Petersen, M.D., Ph.D., a Mayo Clinic neurologist and first author of the editorial, says the most striking feature of the study is the measured effect of exercise on brain structures involved in cognition, rather than motor function. "This provides indirect evidence that aerobic exercise can have a positive impact on cognitive function in addition to physical conditioning," he says. "Another important feature of the study is that these results may apply to older adults, as well. There is good evidence for the value of exercise in midlife, but it is encouraging that there can be positive effects on the brain in later life as well."

Dr. Petersen is the Cora Kanow Professor of Alzheimer's Disease Research and the Chester and Debbie Cadieux Director of the Mayo Clinic Alzheimer's Disease Research Center.

The study's finding of higher gray matter volume associated with cardiorespiratory exercise are in brain regions clinically relevant for cognitive changes in aging, including some involved in Alzheimer's disease. The editorial calls those associations interesting but cautions against concluding that cardiorespiratory fitness correlations would affect Alzheimer's disease.

"This is another piece of the puzzle showing physical activity and physical fitness is protective against aging-related cognitive decline," says Michael Joyner, M.D., a Mayo Clinic anesthesiologist and physiologist, and editorial co-author. "There's already good epidemiological evidence for this, as well as emerging data showing that physical activity and fitness are associated with improved brain blood vessel function. This paper is important because of the volumetric data showing an effect on brain structure."

Dr. Joyner is the Frank R. and Shari Caywood Professor at Mayo Clinic.

Long-term studies on the relationship between exercise and brain health are needed, which will be costly and logistically challenging to produce. "Nevertheless, these data are encouraging," says Clifford Jack Jr., M.D., a Mayo Clinic neuroradiologist and co-author of the editorial. "The findings regarding cardiorespiratory fitness and certain brain structures are unique."

Dr. Jack is the Alexander Family Professor of Alzheimer's Disease Research.

According to Mayo Clinic experts, moderate and regular exercise -- about 150 minutes per week -- is recommended. Good cardiorespiratory fitness also involves:

Not smoking

Following healthy eating habits

Losing weight or maintaining a healthy weight level

Managing blood pressure and avoiding hypertension

Controlling cholesterol levels

Reducing blood sugar, which over time can damage your heart and other organs

University Medicine Greifswald, Germany, also was part of the research project. Katharina Wittfeld, Ph.D., a researcher at the German Center for Neurodegenerative Disease, is first author.

https://www.sciencedaily.com/releases/2020/01/200102094314.htm

Good heart health at age 50 linked to lower dementia risk later in life

Findings support policies to improve midlife cardiovascular health to promote later brain health

August 7, 2019

Science Daily/BMJ

Good cardiovascular health at age 50 is associated with a lower risk of dementia later in life, finds a study of British adults published by The BMJ today.

The researchers say their findings support public health policies to improve cardiovascular health in middle age to promote later brain health.

Dementia is a progressive disease that can start to develop 15-20 years before any symptoms appear, so identifying factors that might prevent its onset is important.

The American Heart Association's "Life Simple 7" cardiovascular health score, initially designed for cardiovascular disease, has been put forward as a potential tool for preventing dementia.

Designed for "primordial" prevention, where the aim is to prevent the development of risk factors themselves in order to affect risk of disease, it is the sum of four behavioural (smoking, diet, physical activity, body mass index) and three biological (fasting glucose, blood cholesterol, blood pressure) metrics, categorised into poor (scores 0-6), intermediate (7-11), and optimal (12-14) cardiovascular health.

But the evidence remains inconsistent. So to address this uncertainty, an international research project led by Séverine Sabia from the French National Institute of Health and Medical Research and University College London, examined the association between the Life Simple 7 cardiovascular health score at age 50 and risk of dementia over the next 25 years.

Their findings are based on cardiovascular data collected from 7,899 British men and women at age 50 in the Whitehall II Study, which is looking at the impact of social, behavioural, and biological factors on long term health.

Participants were free of cardiovascular disease and dementia at age 50. Dementia cases were identified using hospital, mental health services, and death registers until 2017.

Of the 7,899 participants, 347 cases of dementia were recorded over an average follow-up period of 25 years. Average age at dementia diagnosis was 75 years.

After taking account of potentially influential factors, the researchers found that adherence to the Life Simple 7 cardiovascular health recommendations in midlife was associated with a lower risk of dementia later in life.

Compared with an incidence rate of dementia of 3.2 per 1000 person years among the group with a poor cardiovascular score, those with an intermediate score had an incidence of 1.8 per 1000 person years, while those with an optimal score had an incidence of 1.3 per 1000 person years.

This is an observational study, so can't establish cause, and the researchers point to some limitations, for example relying on self-reported measures and potentially missing cases of dementia in patient records.

However, higher cardiovascular health score at age 50 was also associated with higher whole brain and grey matter volumes in MRI scans 20 years later. And reductions in dementia risk were also evident across the continuum of the cardiovascular score, suggesting that even small improvements in cardiovascular risk factors at age 50 may reduce dementia risk in old age, say the researchers.

"Our findings suggest that the Life's Simple 7, which comprises the cardiovascular health score, at age 50 may shape the risk of dementia in a synergistic manner," they write. "Cardiovascular risk factors are modifiable, making them strategically important prevention targets. This study supports public health policies to improve cardiovascular health as early as age 50 to promote cognitive health," they conclude.

Researchers in a linked editorial agree that the study provides further support for the UK Government's recent policy focus on vascular health in midlife. "However, other evidence makes clear that vascular health at 50 is determined by factors earlier in the life course, including inequality and social and economic determinants," they say.

"Reducing the risk of dementia is a leading concern in aging societies. We know that risk can change across generations, and in the UK the prevalence of dementia has decreased by nearly 25% when standardised for age," they add.

They conclude: "Although the Whitehall study cannot reflect the UK's population, estimates obtained from this cohort reinforce the need for action to shift population risk profiles for cognitive decline and dementia across the life course."

https://www.sciencedaily.com/releases/2019/08/190807190812.htm

Feeling young could mean your brain is aging more slowly

The first study to link subjective age to biological age shows that elderly people who feel younger have less signs of brain aging

Science Daily/July 3, 2018

Frontiers

While some people are young at heart, others feel older than their age -- and a recent study finds that this 'subjective age' may reflect brain aging. Researchers found that elderly people who feel younger than their age had a younger estimated brain age, compared with those who felt their age, or older than their age. The study is the first to find a link between brain aging and subjective age.

While everyone gets older, not everyone feels their age. A recent study finds that such feelings, called subjective age, may reflect brain aging. Using MRI brain scans, researchers found that elderly people who feel younger than their age show fewer signs of brain aging, compared with those who feel their age or older than their age. Published in open-access journal Frontiers in Aging Neuroscience, this study is the first to find a link between subjective age and brain aging. The results suggest that elderly people who feel older than their age should consider caring for their brain health.

We tend to think of aging as a fixed process, where our bodies and minds change steadily. However, the passing years affect everyone differently. How old we feel, which is called our subjective age, also varies between people -- with many feeling older or younger than their actual age.

But is subjective age just a feeling or attitude, or does it reflect how our bodies are actually aging? This question intrigued Dr Jeanyung Chey of Seoul National University in Korea.

"Why do some people feel younger or older than their real age?" asks Chey. "Some possibilities include depressive states, personality differences or physical health. However, no-one had investigated brain aging processes as a possible reason for differences in subjective age."

People frequently experience some cognitive impairment as they age. In fact, the brain shows a variety of age-related changes that are reflective of declining neural health, including reductions in gray matter volumes. Recently developed techniques can help researchers to identify brain features associated with aging, to provide an estimated brain age.

Chey and her colleagues applied these techniques to investigate the link between subjective age and brain aging. They performed MRI brain scans in 68 healthy people whose ages ranged from 59-84 years and looked at gray matter volumes in various brain regions. The participants also completed a survey, which included questions on whether they felt older or younger than their age and questions assessing their cognitive abilities and perceptions of their overall health.

People who felt younger than their age were more likely to score higher on a memory test, considered their health to be better and were less likely to report depressive symptoms. Critically, those who felt younger than their age showed increased gray matter volume in key brain regions. The researchers used the MRI data to calculate estimated brain ages for the participants.

"We found that people who feel younger have the structural characteristics of a younger brain," said Chey. "Importantly, this difference remains robust even when other possible factors, including personality, subjective health, depressive symptoms, or cognitive functions, are accounted for."

The researchers hypothesize that those who feel older may be able to sense the aging process in their brain, as their loss of gray matter may make cognitive tasks more challenging.

However, at present the researchers do not know for sure if these brain characteristics are directly responsible for subjective age and will need to carry out long-term studies to understand this link further.

One intriguing possibility is that those who feel younger are more likely to lead a more physically and mentally active life, which could cause improvements in brain health. However, for those who feel older, the opposite could be true.

"If somebody feels older than their age, it could be sign for them to evaluate their lifestyle, habits and activities that could contribute to brain aging and take measures to better care for their brain health," said Chey.

The research is part of a special article collection on assessment of brain aging across the lifespan

https://www.sciencedaily.com/releases/2018/07/180703110014.htm

Sitting is bad for your brain -- not just your metabolism or heart

Thinning in brain regions important for memory linked to sedentary habits

April 12, 2018

Science Daily/University of California - Los Angeles

Studies show that too much sitting, like smoking, increases the risk of heart disease, diabetes and premature death. Researchers found sedentary behavior is linked to thinning in regions of the brain that are critical to memory formation.

UCLA researchers recruited 35 people ages 45 to 75 and asked about their physical activity levels and the average number of hours per day they spent sitting over the previous week. Each person had a high-resolution MRI scan, which provides a detailed look at the medial temporal lobe, or MTL, a brain region involved in the formation of new memories.

The researchers found that sedentary behavior is a significant predictor of thinning of the MTL and that physical activity, even at high levels, is insufficient to offset the harmful effects of sitting for extended periods.

This study does not prove that too much sitting causes thinner brain structures, but instead that more hours spent sitting are associated with thinner regions, researchers said. In addition, the researchers focused on the hours spent sitting, but did not ask participants if they took breaks during this time.

The researchers next hope to follow a group of people for a longer duration to determine if sitting causes the thinning and what role gender, race, and weight might play in brain health related to sitting.

MTL thinning can be a precursor to cognitive decline and dementia in middle-aged and older adults. Reducing sedentary behavior may be a possible target for interventions designed to improve brain health in people at risk for Alzheimer's disease, researchers said.

https://www.sciencedaily.com/releases/2018/04/180412141014.htm

Life in the city: Living near a forest keeps your amygdala healthier

MRI study analyzes stress-processing brain regions in older city dwellers

October 18, 2017

Science Daily/Max-Planck-Gesellschaft

A new study examined the relationship between the availability of nature near city dwellers' homes and their brain health. Its findings are relevant for urban planners among others.

Noise, pollution, and many people in a confined space: Life in a city can cause chronic stress. City dwellers are at a higher risk of psychiatric illnesses such as depression, anxiety disorders, and schizophrenia than country dwellers. Comparisons show higher activity levels in city dwellers' than in country dwellers' amygdala -- a central nucleus in the brain that plays an important role in stress processing and reactions to danger. Which factors can have a protective influence? A research team led by psychologist Simone Kühn has examined which effects nature near people's homes such as forest, urban green, or wasteland has on stress-processing brain regions such as the amygdala. "Research on brain plasticity supports the assumption that the environment can shape brain structure and function. That is why we are interested in the environmental conditions that may have positive effects on brain development. Studies of people in the countryside have already shown that living close to nature is good for their mental health and well-being. We therefore decided to examine city dwellers," explains first author Simone Kühn, who led the study at the Max Planck Institute for Human Development and now works at the University Medical Center Hamburg-Eppendorf (UKE).

Indeed, the researchers found a relationship between place of residence and brain health: those city dwellers living close to a forest were more likely to show indications of a physiologically healthy amygdala structure und were therefore presumably better able to cope with stress. This effect remained stable when differences in educational qualifications and income levels were controlled for. However, it was not possible to find an association between the examined brain regions and urban green, water, or wasteland. With these data, it is not possible to distinguish whether living close to a forest really has positive effects on the amygdala or whether people with a healthier amygdala might be more likely to select residential areas close to a forest. Based on present knowledge, however, the researchers regard the first explanation as more probable. Further longitudinal studies are necessary to accumulate evidence.

The participants in the present study are from the Berlin Aging Study II (BASE-II) -- a larger longitudinal study examining the physical, psychological, and social conditions for healthy aging. In total, 341 adults aged 61 to 82 years took part in the present study. Apart from carrying out memory and reasoning tests, the structure of stress-processing brain regions, especially the amygdala, was assessed using magnetic resonance imaging (MRI). In order to examine the influence of nature close to peoples' homes on these brain regions, the researchers combined the MRI data with geoinformation about the participants' places of residence. This information stemmed from the European Environment Agency's Urban Atlas, which provides an overview of urban land use in Europe.

"Our study investigates the connection between urban planning features and brain health for the first time," says co-author Ulman Lindenberger, Director of the Center for Lifespan Psychology at the Max Planck Institute for Human Development. By 2050, almost 70 percent of the world population is expected to be living in cities. These results could therefore be very important for urban planning. In the near future, however, the observed association between the brain and closeness to forests would need to be confirmed in further studies and other cities, stated Ulman Lindenberger.

https://www.sciencedaily.com/releases/2017/10/171018113515.htm

Exercise results in larger brain size and lowered dementia risk

August 2, 2016

Science Daily/University of California - Los Angeles Health Sciences
Regular physical activity for older adults could lead to higher brain volumes and a reduced risk for developing dementia. It particularly affected the size of the hippocampus, which controls short-term memory, and its protective effect against dementia was strongest in people age 75 and older

Using the landmark Framingham Heart Study to assess how physical activity affects the size of the brain and one's risk for developing dementia, UCLA researchers found an association between low physical activity and a higher risk for dementia in older individuals. This suggests that regular physical activity for older adults could lead to higher brain volumes and a reduced risk for developing dementia.

The researchers found that physical activity particularly affected the size of the hippocampus, which is the part of the brain controlling short-term memory. Also, the protective effect of regular physical activity against dementia was strongest in people age 75 and older.

Though some previous studies have found an inverse relationship between levels of physical activity and cognitive decline, dementia and Alzheimer's disease, others have failed to find such an association. The Framingham study was begun in 1948 primarily as a way to trace factors and characteristics leading to cardiovascular disease, but also examining dementia and other physiological conditions. For this study, the UCLA researchers followed an older, community-based cohort from the Framingham study for more than a decade to examine the association between physical activity and the risk for incident dementia and subclinical brain MRI markers of dementia.

The researchers assessed the physical activity indices for both the original Framingham cohort and their offspring who were age 60 and older. They examined the association between physical activity and risk of any form of dementia (regardless of the cause) and Alzheimer's disease for 3,700 participants from both cohorts who were cognitively intact. They also examined the association between physical activity and brain MRI in about 2,000 participants from the offspring cohort.

What this all means: one is never too old to exercise for brain health and to stave off the risk for developing dementia.

Science Daily/SOURCE :https://www.sciencedaily.com/releases/2016/08/160802103723.htm