Exercise does seem to be key” to maintaining and even improving our ability to think as we age. – J. Carson Smith
In a groundbreaking study, researchers have discovered that exercise holds the key to sharpening our thinking and keeping our brains healthy as we age, even if we haven’t been active earlier in life. The study, led by Professor J. Carson Smith from the University of Maryland at College Park, focused on previously sedentary individuals in their 70s and 80s, some of whom had already experienced cognitive decline. The remarkable findings demonstrate that engaging in exercise resulted in improved brain function among the participants.
As we journey through life, many of us have witnessed the frustrating decline of mental agility, which typically begins in early middle age and accelerates from there. Forgetfulness becomes more prevalent, and simple tasks like remembering names or recalling where we parked the car become challenging. This decline occurs partly due to the natural fraying of the brain’s structure and function over time. Neurons weaken or die, and the connections between individual neurons and broader networks within the brain start to wither.
To address the pressing question of whether we can slow or reverse this decline in brain function, Professor Smith and his team enlisted 33 volunteers in their 70s and 80s, half of whom were experiencing mild cognitive impairment, a precursor to Alzheimer’s disease. The participants underwent a series of physiological and mental tests, including recounting a brief story and undergoing a functional MRI scan to measure electrical activity in their brains.
Subsequently, half of the volunteers, including those with mild cognitive impairment, embarked on an exercise regimen that involved brisk walking for approximately 30 minutes, four times a week, under supervised conditions. The remaining volunteers remained inactive. After four months, all participants repeated the initial tests, and the results were striking. The exercisers, including those with mild cognitive impairment, demonstrated better performance on the cognitive tests, particularly in the version involving story recall. In contrast, the sedentary volunteers showed no such improvement.
However, what made the study even more intriguing were the changes observed in the brains of the exercisers. Prior to the study, brain scans of the older volunteers revealed weak or scattershot connections within major brain networks. The brain works most efficiently when distinct networks interact and connect, enabling complex thinking and memory formation. Brain scans captured the process, with connected brain networks lighting up together, akin to synchronized Christmas lights.
Remarkably, after four months of exercise, the scans revealed stronger connections in the brains of the participants. Cells and entire networks were now lighting up simultaneously, a hallmark of enhanced cognitive function. These findings underscore the transformative power of exercise on the brain and its ability to reinvigorate connections vital for optimal thinking.
To delve deeper into how exercise influences aging brains, researchers have turned to studying mice. It has been known for some time that adult mammals, including humans, generate new neurons, a process called neurogenesis. Exercise amplifies this neurogenesis, with running mice producing two to three times as many new neurons compared to sedentary mice.
However, the key lies in ensuring that these new neurons survive and integrate into broader brain networks. In a recent study published in eNeuro, young adult mice were divided into two groups: runners and sedentary animals. Researchers injected a modified virus into all the animals’ brains, marking the newborn neurons with a phosphorescent dye. For six months, the runners continued to run while the sitters remained still. At the end of the study, researchers introduced a substance that traced the connections of these cells.
The findings revealed that the running mice not only generated more neurons during their initial running period but, as they neared retirement age (in rodent terms), these same cells exhibited more intricate and extensive connections within the animals’ brain networks compared to sedentary mice. The neurons of the active mice were better connected, highlighting the profound impact of exercise on neural wiring.
So, what does this mean for those of us who are not yet elderly or mice? According to Professor Smith, the results should be encouraging, especially for individuals concerned about the early signs of cognitive decline. In his study, even once-sedentary older individuals with mild cognitive impairment experienced improvements in their brain’s connections and cognitive abilities with just a few hours of walking per week.
However, the findings also emphasize the importance of starting to exercise at a younger age. The young mice that engaged in running likely built a “cognitive reserve” of healthy neurons and connections, surpassing their inactive counterparts. Henriette van Praag, senior author of the mouse study and an associate professor of biomedical science at Florida Atlantic University, suggests that initiating exercise at a young age and maintaining it throughout life is even more beneficial.
Russell Swerdlow, a professor of neurology and director of the University of Kansas Alzheimer’s Disease Research Center, who was not involved in the study, supports this notion. He believes that based on the current state of scientific knowledge, it is advisable to pursue physical activity during youth and continue engaging in it during middle age and beyond.
The research reveals the potential for exercise to serve as a proverbial fountain of youth for our aging brains. By incorporating regular physical activity into our lives, we can enhance neural connections, promote cognitive function, and potentially mitigate the cognitive decline associated with aging. It is never too late to start reaping the benefits of exercise, but starting early and maintaining an active lifestyle can set the stage for a healthier and more vibrant cognitive future.
As we gain a deeper understanding of the transformative effects of exercise on the brain, it is essential to spread awareness about the powerful connection between physical activity and cognitive health. So, let us lace up our sneakers, step outside, and embrace the potential to unlock the full potential of our minds through the simple act of movement. In the pursuit of a sharper mind and a healthier life, exercise is undoubtedly an invaluable tool at our disposal.
