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
Exercise is good for the aging brain
Researchers find a single bout of exercise boosts cognition, memory performance in some older people
August 26, 2019
Science Daily/University of Iowa
Researchers have found that a single bout of exercise benefits some older people's brains. In experiments in which participants aged 60 to 80 exercised once and multiple times, the researchers found some individuals showed improved cognitive functions and working memory.
Exercise seems to endow a wealth of benefits, from the release of happiness-inducing hormones to higher physical fitness. New research shows it may provide a boost to the mind too.
University of Iowa researchers have found that a single bout of exercise improves cognitive functions and working memory in some older people. In experiments that included physical activity, brain scans, and working memory tests, the researchers also found that participants experienced the same cognitive benefits and improved memory from a single exercise session as they did from longer, regular exercise.
"One implication of this study is you could think of the benefits day by day," says Michelle Voss, assistant professor in the Department of Psychological and Brain Sciences and the study's corresponding author. "In terms of behavioral change and cognitive benefits from physical activity, you can say, 'I'm just going to be active today. I'll get a benefit.' So, you don't need to think of it like you're going to train for a marathon to get some sort of optimal peak of performance. You just could work at it day by day to gain those benefits."
Previous research has shown exercise can confer a mental boost. But the benefits vary: One person may improve cognitively and have improved memory, while another person may show little to no gain.
Limited research has been done on how a single bout of physical activity may affect cognition and working memory specifically in older populations, despite evidence that some brain functions slip as people age.
Voss wanted to tease out how a single session of exercise may affect older individuals. Her team enrolled 34 adults between 60 and 80 years of age who were healthy but not regularly active. Each participant rode a stationary bike on two separate occasions -- with light and then more strenuous resistance when pedaling -- for 20 minutes. Before and after each exercise session, each participant underwent a brain scan and completed a memory test.
In the brain scan, the researchers examined bursts of activity in regions known to be involved in the collection and sharing of memories. In the working memory tests, each participant used a computer screen to look at a set of eight young adult faces that rotated every three seconds -- flashcard style -- and had to decide when a face seen two "cards" previously matched the one they were currently viewing.
After a single exercise session, the researchers found in some individuals increased connectivity between the medial temporal (which surrounds the brain's memory center, the hippocampus) and the parietal cortex and prefrontal cortex, two regions involved in cognition and memory. Those same individuals also performed better on the memory tests. Other individuals showed little to no gain.
The boost in cognition and memory from a single exercise session lasted only a short while for those who showed gains, the researchers found.
"The benefits can be there a lot more quickly than people think," Voss says. "The hope is that a lot of people will then keep it up because those benefits to the brain are temporary. Understanding exactly how long the benefits last after a single session, and why some benefit more than others, are exciting directions for future research."
The participants also engaged in regular exercise, pedaling on a stationary bike for 50 minutes three times a week for three months. One group engaged in moderate-intensity pedaling, while another group had a mostly lighter workout in which the bike pedals moved for them.
Most individuals in the moderate and lighter-intensity groups showed mental benefits, judging by the brain scans and working memory tests given at the beginning and at the end of the three-month exercise period. But the brain gains were no greater than the improvements from when they had exercised a single time.
"The result that a single session of aerobic exercise mimics the effects of 12 weeks of training on performance has important implications both practically and theoretically," the authors write.
The researchers note their study had a small participant pool, with a homogenous population that excluded anyone with chronic health conditions or who were taking beta-blockers.
To address those limitations, Voss has expanded her participant pool in a current, five-year study to confirm the initial findings and learn more about how exercise alters older people's brains. The participants are healthy older individuals who are not physically active, similar to the participants' profile in the study's results reported here.
The National Institute on Aging, part of the National Institutes of Health, funded the research.
https://www.sciencedaily.com/releases/2019/08/190826110409.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