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
Aerobics may be a smart workout for your brain at any age
May 13, 2020
Science Daily/American Academy of Neurology
It's never too late to lace up some sneakers and work up a sweat for brain health, according to a study published in the May 13, 2020, online issue of Neurology®, the medical journal of the American Academy of Neurology. The study suggests older adults, even couch potatoes, may perform better on certain thinking and memory tests after just six months of aerobic exercise.
"As we all find out eventually, we lose a bit mentally and physically as we age. But even if you start an exercise program later in life, the benefit to your brain may be immense," said study author Marc J. Poulin, Ph.D., D.Phil., from the Cumming School of Medicine at the University of Calgary in Alberta, Canada. "Sure, aerobic exercise gets blood moving through your body. As our study found, it may also get blood moving to your brain, particularly in areas responsible for verbal fluency and executive functions. Our finding may be important, especially for older adults at risk for Alzheimer's and other dementias and brain disease."
The study involved 206 adults who prior to starting the six-month exercise intervention worked out no more than four days per week at a moderate intensity for 30 minutes or less, or no more than two days per week a high intensity for 20 minutes or less per day. They had an average age of 66 and no history of heart or memory problems. Participants were given thinking and memory tests at the start of the study, as well as an ultrasound to measure blood flow in the brain. Physical testing was repeated at three months, and thinking and physical testing repeated at the end of the six months.
Participants were enrolled in a supervised aerobic exercise program held three days a week. As they progressed through the program, they increased their workout from an average of 20 minutes a day to an average of at least 40 minutes. In addition, people were asked to work out on their own once a week.
Researchers found that after six months of exercise, participants improved by 5.7% on tests of executive function, which includes mental flexibility and self-correction. Verbal fluency, which tests how quickly you can retrieve information, increased by 2.4%.
"This change in verbal fluency is what you'd expect to see in someone five years younger," Poulin said.
Before and after six months of aerobic activity, the participants' average peak blood flow to the brain was measured using ultrasound. Blood flow rose from an average of 51.3 centimeters per second (cm/sec) to an average of 52.7 cm/sec, a 2.8% increase. The increase in blood flow with exercise was associated with a number of modest but significant improvements in aspects of thinking that usually decline as we age, Poulin said.
"Our study showed that six months' worth of vigorous exercise may pump blood to regions of the brain that specifically improve your verbal skills as well as memory and mental sharpness," said Poulin. "At a time when these results would be expected to be decreasing due to normal aging, to have these types of increases is exciting."
A limitation of the study was that the people doing the exercise were not compared to a similar group of people who were not exercising, so the results may have been due to other factors, although the researchers tried to control for this by testing participants twice over six months before the start of the program. In addition, some of the exercise was unsupervised, so the amount reported may be unreliable.
https://www.sciencedaily.com/releases/2020/05/200513171130.htm
Exercise could slow withering effects of Alzheimer's
Imaging shows less brain deterioration in physically active people at high risk for dementia
September 17, 2019
Science Daily/UT Southwestern Medical Center
Exercising several times a week may delay brain deterioration in people at high risk for Alzheimer's disease, according to a study that scientists say merits further research to establish whether fitness can affect the progression of dementia.
Research from UT Southwestern found that people who had accumulation of amyloid beta in the brain -- a hallmark of Alzheimer's disease -- experienced slower degeneration in a region of the brain crucial for memory if they exercised regularly for one year.
Although exercise did not prevent the eventual spread of toxic amyloid plaques blamed for killing neurons in the brains of dementia patients, the findings suggest an intriguing possibility that aerobic workouts can at least slow down the effects of the disease if intervention occurs in the early stages.
"What are you supposed to do if you have amyloid clumping together in the brain? Right now doctors can't prescribe anything," said Dr. Rong Zhang, who led the clinical trial that included 70 participants ages 55 and older. "If these findings can be replicated in a larger trial, then maybe one day doctors will be telling high-risk patients to start an exercise plan. In fact, there's no harm in doing so now."
Reduced brain atrophy
The study published in the Journal of Alzheimer's Disease compared cognitive function and brain volume between two groups of sedentary older adults with memory issues: One group did aerobic exercise (at least a half-hour workout four to five times weekly), and another group did only flexibility training.
Both groups maintained similar cognitive abilities during the trial in areas such as memory and problem solving. But brain imaging showed that people from the exercise group who had amyloid buildup experienced slightly less volume reduction in their hippocampus -- a memory-related brain region that progressively deteriorates as dementia takes hold.
"It's interesting that the brains of participants with amyloid responded more to the aerobic exercise than the others," said Dr. Zhang, who conducted the trial at the Institute for Exercise and Environmental Medicine. "Although the interventions didn't stop the hippocampus from getting smaller, even slowing down the rate of atrophy through exercise could be an exciting revelation."
However, Dr. Zhang notes that more research is needed to determine how or if the reduced atrophy rate benefits cognition.
Elusive answers
The search for dementia therapies 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 UT Southwestern discovery published last year that is guiding efforts to detect the condition before symptoms arise. Yet the billions of dollars spent on trying to prevent or slow dementia have yielded no proven treatments that would make an early diagnosis actionable for patients.
Fitness and brain health
Dr. Zhang is among a group of scientists across the world trying to determine if exercise may be the first such therapy.
His latest research builds upon numerous studies suggesting links between fitness and brain health. 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. Research in mice has similarly shown exercise correlated with slower deterioration of the hippocampus -- findings that prompted Dr. Zhang to investigate whether the same effects could be found in people.
"I'm excited about the results, but only to a certain degree," Dr. Zhang said. "This is a proof-of-concept study, and we can't yet draw definitive conclusions."
Expanded research
Dr. Zhang is leading a five-year national clinical trial that aims to dig deeper into potential correlations between exercise and dementia.
The trial, which includes six medical centers across the country, involves more than 600 older adults (ages 60-85) at high risk of developing Alzheimer's disease. The study will measure whether aerobic exercise and taking specific medications to reduce high blood pressure and cholesterol can help preserve brain volume and cognitive abilities.
"Understanding the molecular basis for Alzheimer's disease is important," Dr. Zhang said. "But the burning question in my field is, 'Can we translate our growing knowledge of molecular biology into an effective treatment?' We need to keep looking for answers.
https://www.sciencedaily.com/releases/2019/09/190917124832.htm
Physical activity may protect against new episodes of depression
November 5, 2019
Science Daily/Massachusetts General Hospital
Increased levels of physical activity can significantly reduce the odds of depression, even among people who are genetically predisposed to the condition, according to a new study from researchers at Massachusetts General Hospital (MGH). In a paper published in the journal Depression and Anxiety, the team reported that individuals who engaged in at least several hours of exercise each week were less likely to be diagnosed with a new episode of depression, even in the face of high genetic risk for the disorder.
Drawing on genomic and electronic health record data from nearly 8,000 participants in the Partners Healthcare Biobank, the new study is the first to show how physical activity can influence depression despite genetic risk. Researchers followed patients who filled out a survey about their lifestyle habits (including physical activity) when they enrolled in the Biobank. They then mined millions of electronic health record data points over the next two years and identified people who received diagnoses related to depression. They also calculated genetic risk scores for each participant, combining information across the entire genome into a single score that reflects a person's inherited risk for depression.
What they found was that people with higher genetic risk were more likely to be diagnosed with depression over the next two years. Significantly, though, people who were more physically active at baseline were less likely to develop depression, even after accounting for genetic risk. In addition, higher levels of physical activity were protective for people even with the highest genetic risk scores for depression.
"Our findings strongly suggest that, when it comes to depression, genes are not destiny and that being physically active has the potential to neutralize the added risk of future episodes in individuals who are genetically vulnerable," says Karmel Choi, PhD, of MGH and the Harvard T.H. Chan School of Public Health, and lead author of the study. "On average, about 35 additional minutes of physical activity each day may help people to reduce their risk and protect against future depression episodes."
The researchers found that both high-intensity forms of activity, such as aerobic exercise, dance and exercise machines, and lower-intensity forms, including yoga and stretching, were linked to decreased odds of depression. Overall, individuals could see a 17 percent reduction in odds of a new episode of depression for each added four-hour block of activity per week.
Depression represents the leading cause of disability worldwide. Despite its massive health burden, strategies to combat depression remain limited and the public's understanding of robust and modifiable protective factors is incomplete. "We provide promising evidence that primary care and mental health providers can use to counsel and make recommendations to patients that here is something meaningful they can do to lower their risk even if they have a family history of depression," says Choi.
Senior author Jordan Smoller MD, added, "In general our field has been lacking actionable ways of preventing depression and other mental health conditions. I think this research shows the value of real-world healthcare data and genomics to provide answers that can help us to reduce the burden of these diseases."
Beyond physical activity, the MGH team continues to leverage the Partners Biobank and other large-scale studies to explore modifiable ways that individuals might reduce their risk of depression. "We believe there may be many factors could be part of an overall strategy for improving resilience and preventing depression," emphasizes Choi. "The magnitude of depression around the world underscores the need for effective strategies that can impact as many people as possible."
https://www.sciencedaily.com/releases/2019/11/191105113510.htm
Aerobic exercise may mildly delay, slightly improve Alzheimer's symptoms
January 26, 2018
Science Daily/American Geriatrics Society
Geriatrics experts have suggested that exercising can improve brain health in older adults. However, not all studies of exercise and older adults have proven the benefits of exercise. A team of researchers designed a study to learn whether exercise could delay or improve AD symptoms. They reviewed 19 studies that examined the effect of an exercise training program on cognitive function in older adults who were at risk for or diagnosed with AD.
Geriatrics experts have suggested that exercising can improve brain health in older adults. The World Health Organization (WHO) has recommendations for how much older adults should exercise. They suggest that older adults perform 150 minutes a week of moderate exercise (such as brisk walking), 75 minutes a week of vigorous aerobic training, or a combination of the two types. The WHO also recommends older adults perform muscle-strengthening exercises on at least two or more days a week.
However, not all studies of exercise and older adults have proven the benefits of exercise. We don't know for sure whether exercise slows mental decline or improves older adults' ability to think and make decisions.
A team of researchers designed a study to learn whether exercise could delay or improve AD symptoms. They reviewed 19 studies that examined the effect of an exercise training program on cognitive function in older adults who were at risk for or diagnosed with AD. The studies included 1,145 older adults, most of whom were in their mid-to late 70s. Of the participants, 65 percent were at risk for AD and 35 percent had been diagnosed with AD.
The researchers published their findings in the Journal of the American Geriatrics Society.
As the researchers examined the studies, they discovered that older adults who did aerobic exercise by itself experienced a three times greater level of improvement in cognitive function than those who participated in combined aerobic training and strength training exercises. The researchers also confirmed that the amount of exercise WHO recommends for older adults was reinforced by the studies they examined.
Finally, the researchers found that older adults in the no-exercise control groups in the studies faced declines in cognitive function. Meanwhile, the older adults who exercised showed small improvements in cognitive function no matter what type of exercise they did.
The research team concluded that this study may be the first to show that for older adults who are at risk for or who have AD, aerobic exercise may be more effective than other types of exercise in preserving the ability to think and make decisions.
https://www.sciencedaily.com/releases/2018/01/180126130325.htm
Aerobic exercise may reduce the risk of dementia
September 8, 2011
Science Daily/Mayo Clinic
Any exercise that gets the heart pumping may reduce the risk of dementia and slow the condition's progression once it starts, a new study finds. Researchers examined the role of aerobic exercise in preserving cognitive abilities and concluded that it should not be overlooked as an important therapy against dementia.
"We culled through all the scientific literature we could find on the subject of exercise and cognition, including animal studies and observational studies, reviewing over 1,600 papers, with 130 bearing directly on this issue. We attempted to put together a balanced view of the subject," says J. Eric Ahlskog, M.D., Ph.D., a neurologist at Mayo Clinic.
"We concluded that you can make a very compelling argument for exercise as a disease-modifying strategy to prevent dementia and mild cognitive impairment, and for favorably modifying these processes once they have developed."
The researchers note that brain imaging studies have consistently revealed objective evidence of favorable effects of exercise on human brain integrity. Also, they note, animal research has shown that exercise generates trophic factors that improve brain functioning, plus exercise facilitates brain connections (neuroplasticity).
http://www.sciencedaily.com/releases/2011/09/110907163919.htm