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
Experts review evidence yoga is good for the brain
December 12, 2019
Science Daily/University of Illinois at Urbana-Champaign, News Bureau
Scientists have known for decades that aerobic exercise strengthens the brain and contributes to the growth of new neurons, but few studies have examined how yoga affects the brain. A review of the science finds evidence that yoga enhances many of the same brain structures and functions that benefit from aerobic exercise.
The review, published in the journal Brain Plasticity, focused on 11 studies of the relationship between yoga practice and brain health. Five of the studies engaged individuals with no background in yoga practice in one or more yoga sessions per week over a period of 10-24 weeks, comparing brain health at the beginning and end of the intervention. The other studies measured brain differences between individuals who regularly practice yoga and those who don't.
Each of the studies used brain-imaging techniques such as MRI, functional MRI or single-photon emission computerized tomography. All involved Hatha yoga, which includes body movements, meditation and breathing exercises.
"From these 11 studies, we identified some brain regions that consistently come up, and they are surprisingly not very different from what we see with exercise research," said University of Illinois kinesiology and community health professor Neha Gothe, who led the research with Wayne State University psychology professor Jessica Damoiseaux.
"For example, we see increases in the volume of the hippocampus with yoga practice," Gothe said. Many studies looking at the brain effects of aerobic exercise have shown a similar increase in hippocampus size over time, she said.
The hippocampus is involved in memory processing and is known to shrink with age, Gothe said. "It is also the structure that is first affected in dementia and Alzheimer's disease."
Though many of the studies are exploratory and not conclusive, the research points to other important brain changes associated with regular yoga practice, Damoiseaux said. The amygdala, a brain structure that contributes to emotional regulation, tends to be larger in yoga practitioners than in their peers who do not practice yoga. The prefrontal cortex, cingulate cortex and brain networks such as the default mode network also tend to be larger or more efficient in those who regularly practice yoga.
"The prefrontal cortex, a brain region just behind the forehead, is essential to planning, decision-making, multitasking, thinking about your options and picking the right option," Damoiseaux said. "The default mode network is a set of brain regions involved in thinking about the self, planning and memory."
Like the amygdala, the cingulate cortex is part of the limbic system, a circuit of structures that plays a key role in emotional regulation, learning and memory, she said.
The studies also find that the brain changes seen in individuals practicing yoga are associated with better performance on cognitive tests or measures of emotional regulation.
The discovery that yoga may have similar effects on the brain to aerobic exercise is intriguing and warrants more study, Gothe said.
"Yoga is not aerobic in nature, so there must be other mechanisms leading to these brain changes," she said. "So far, we don't have the evidence to identify what those mechanisms are."
She suspects that enhancing emotional regulation is a key to yoga's positive effects on the brain. Studies link stress in humans and animals to shrinkage of the hippocampus and poorer performance on tests of memory, for example, she said.
"In one of my previous studies, we were looking at how yoga changes the cortisol stress response," Gothe said. "We found that those who had done yoga for eight weeks had an attenuated cortisol response to stress that was associated with better performance on tests of decision-making, task-switching and attention."
Yoga helps people with or without anxiety disorders manage their stress, Gothe said.
"The practice of yoga helps improve emotional regulation to reduce stress, anxiety and depression," she said. "And that seems to improve brain functioning."
The researchers say there is a need for more -- and more rigorous -- research into yoga's effects on the brain. They recommend large intervention studies that engage participants in yoga for months, match yoga groups with active control groups, and measure changes in the brain and performance on cognitive tests using standard approaches that allow for easy comparisons with other types of exercise.
"The science is pointing to yoga being beneficial for healthy brain function, but we need more rigorous and well-controlled intervention studies to confirm these initial findings," Damoiseaux said.
https://www.sciencedaily.com/releases/2019/12/191212105851.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