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
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
Short-term exercise equals big-time brain boost
Even a one-time, brief burst of exercise can improve focus, problem-solving
December 21, 2017
Science Daily/University of Western Ontario
A 10-minute, one-time burst of exercise can measurably boost your brain power, at least temporarily, researchers at Western University in London, Canada, have found.
While other studies have showed brain-health benefits after 20-minutes of a single-bout of exercise, or following commitment to a long-term (24-week) exercise program, this research suggests even 10 minutes of aerobic activity can prime the parts of the brain that help us problem-solve and focus.
"Some people can't commit to a long-term exercise regime because of time or physical capacity," said Kinesiology Prof. Matthew Heath, who is also a supervisor in the Graduate Program in Neuroscience and, with master's student Ashna Samani, conducted the study. "This shows that people can cycle or walk briskly for a short duration, even once, and find immediate benefits."
During the study, research participants either sat and read a magazine or did 10 minutes of moderate-to-vigorous exercise on a stationary bicycle. Following the reading and exercise session, the researchers used eye-tracking equipment to examine participants' reaction times to a cognitively demanding eye movement task. The task was designed to challenge areas of the brain responsible for executive function such as decision-making and inhibition.
"Those who had exercised showed immediate improvement. Their responses were more accurate and their reaction times were up to 50 milliseconds shorter than their pre-exercise values. That may seem minuscule but it represented a 14-per-cent gain in cognitive performance in some instances," said Heath, who is also an associate member of Western's Brain and Mind institute. He is conducting a study now to determine how long the benefits may last following exercise.
The work has significance for older people in early stages of dementia who may be less mobile, he said, and for anyone else looking to gain quick a mental edge in their work.
"I always tell my students before they write a test or an exam or go into an interview -- or do anything that is cognitively demanding -- they should get some exercise first," Heath said. "Our study shows the brain's networks like it. They perform better.
https://www.sciencedaily.com/releases/2017/12/171221122543.htm
Scientists identify protein linking exercise to brain health
October 10, 2013
Science Daily/Dana-Farber Cancer Institute
A protein that is increased by endurance exercise has been isolated and given to non-exercising mice, in which it turned on genes that promote brain health and encourage the growth of new nerves involved in learning and memory, report scientists from Dana-Farber Cancer Institute and Harvard Medical School.
The findings, reported in the journal Cell Metabolism, help explain the well-known capacity of endurance exercise to improve cognitive function, particularly in older people. If the protein can be made in a stable form and developed into a drug, it might lead to improved therapies for cognitive decline in older people and slow the toll of neurodegenerative diseases such Alzheimer's and Parkinson's, according to the investigators.
"What is exciting is that a natural substance can be given in the bloodstream that can mimic some of the effects of endurance exercise on the brain," said Bruce Spiegelman, PhD, of Dana-Farber and HMS. He is co-senior author of the publication with Michael E. Greenberg, PhD, chair of neurobiology at HMS.
The Spiegelman group previously reported that the protein, called FNDC5, is produced by muscular exertion and is released into the bloodstream as a variant called irisin. In the new research, endurance exercise -- mice voluntarily running on a wheel for 30 days -- increased the activity of a metabolic regulatory molecule, PGC-1α, in muscles, which spurred a rise in FNDC5 protein. The increase of FNDC5 in turn boosted the expression of a brain-health protein, BDNF (brain-derived neurotrophic protein) in the dentate gyrus of the hippocampus, a part of the brain involved in learning and memory.
It has been found that exercise stimulates BDNF in the hippocampus, one of only two areas of the adult brain that can generate new nerve cells. BDNF promotes development of new nerves and synapses -- connections between nerves that allow learning and memory to be stored -- and helps preserve the survival of brain cells.
How exercise raises BDNF activity in the brain wasn't known; the new findings linking exercise, PGC-1α, FNDC5 and BDNF provide a molecular pathway for the effect, although Spiegelman and his colleagues suggest there are probably others.
Having shown that FNDC5 is a molecular link between exercise and increased BDNF in the brain, the scientists asked whether artificially increasing FNDC5 in the absence of exercise would have the same effect. They used a harmless virus to deliver the protein to mice through the bloodstream, in hopes the FNDC5 could reach the brain and raise BDNF activity. Seven days later, they examined the mouse brains and observed a significant increase in BDNF in the hippocampus.
"Perhaps the most exciting result overall is that peripheral deliver of FNDC5 with adenoviral vectors is sufficient to induce central expression of Bdnf and other genes with potential neuroprotective functions or those involved in learning and memory," the authors said. Spiegelman cautioned that further research is needed to determine whether giving FNDC5 actually improves cognitive function in the animals. The scientists also aren't sure whether the protein that got into the brain is FNDC5 itself, or irisin, or perhaps another variant of the protein.
http://www.sciencedaily.com/releases/2013/10/131010204803.htm