Do you hate brisk walking and fast dancing? If you are more than 50 years old, consider sticking with me for at least the first few paragraphs of this column. You may change your mind.
We all know that exercise, even a brisk, minimum stop-and-sniff walk with Duke or Molly, contributes to a healthy heart and musculoskeletal system. This isn’t about that.
It’s also not just about grey matter, that portion of our brain with which we think and remember. We know our cognitive abilities, primarily in later life, respond well to exercise.
It is, however, about white brain matter, and new studies made possible by improved MRI (magnetic resonance imaging) technology, that conclude exercise also effects the function of this area of our brain.
In a very generalized sense, our brain and spinal cord contain grey matter and white matter, and more is better, especially as we age.
Grey matter tissue is primarily made up of cell bodies called soma, which house our neurons’ nuclei, capillary blood vessels, and glial cells, the group name for numerous brain cells essential to neural development, modulation of synaptic action and recovery from neural injury, among other functions. When we think of grey matter, we think of executive function and factors crucial to learning such as attention span, concentration, memory and thought process. Grey matter is also responsible for motor control, coordination and precise muscular control. Yet all these functions are dependent on our brain having a large volume of healthy white matter.
White matter areas of the brain consist primarily of axons, long filaments that extend from the soma, and astrocytes. Axons are sheathed in a myelin protein which is high in white-hued lipid fats for protection, hence the term white matter. Axon tracts are the connections or pathways through which our brain and spinal cord cells communicate the information provided by our grey matter. Astrocyctes, part of our white matter, assist in maintaining the correct chemical balance to enhance oxygenation and regulate blood flow within the brain, enabling healthy myelinated axons to better transmit the electrical signals essential to sensory function and motor control.
Traditionally, studies on the impact on our brains of cardio-respiratory exercise such as brisk walking have dealt with grey matter.
A study by the German Centre for Neurodegenerative Diseases presented in the Mayo Clinic Proceedings journal is an example. The study “provides new evidence of an association between cardio-respiratory fitness and increased gray matter volume, improved brain health and a deceleration in the decline of grey matter.” This study involved 2000 adults and was carried out from 1997 to 2012, almost a decade ago.
A paper from the United States National Centre for Biotechnology Information provided the results of a meta-analyses of similar studies from between 2003 and 2012, and went further in its findings, suggesting that the effects of exercise on our brains might not be uniform in all brain areas for participants aged 55 to 79 years.
The results from meta-analyses have suggested that the brain regions showing the most rapid age-related losses in volume might also be the regions most sensitive to a more physically active lifestyle
“The effects appear to be general in the sense that many different cognitive domains are improved after several months of aerobic exercise, but specific in the sense that executive functions are improved more than other cognitive domains. This reasoning fits in line with evidence that the brain does not uniformly atrophy in late life and that some regions (i.e., prefrontal cortex) may be more sensitive to the effects of aging than other brain areas. In other words, the results from meta-analyses have suggested that the brain regions showing the most rapid age-related losses in volume might also be the regions most sensitive to a more physically active lifestyle.”
Although this analysis was apolitical, one of the conclusions was that such data could be used to change public policy on the appropriateness of physical activity as a method of influencing brain health. This information supported known evidence that increased physical activity promotes improved blood vessel function in the brain, including better oxygen delivery.
They needn’t have been so subtle. These results are clearly a call to action for those of us in our 60s and beyond that wish to participate in maintaining our mental vibrancy; and we haven’t even got to the white matter research yet.
An multi-authored study titled, “White matter plasticity in healthy older adults: the effects of aerobic exercise,” published in June 2021, on Neuroimage, an open-source online medical journal focused on neurology, concludes that aerobic exercise does in fact improve the function of our brain’s white matter. Our brain and nervous system’s white matter can renew itself through neurogenesis, and exercise enhances this process.
Two hundred and fifty sedentary women and men over the age of 60 were tested for their current level of aerobic fitness and cognitive skills. Advanced MRI scanning technology was used to measure the functional capacity and health of their white matter. With this data recorded as a base line, the participants were divided into groups for six months of physical activity. A control group did stretching and balance training three times a week, another walked briskly thrice weekly for 40 minutes per session, and a third group learned and practiced group dance, including line dancing.
After the six months of this training, the scientists and physiologists conducting the tests found that the group who did non-aerobic stretching and balance training showed declining white matter health.
The dancers’ and walkers’ bodies and brains had physically changed. Their aerobic capacities had increased, and the volume of their brain’s white matter had also increased. The report stated, “Their white matter seemed renewed. Nerve fibers in certain portions of their brains looked larger, and any tissue lesions had shrunk.”
However, it was only the brisk walkers, the most active group physically, who improved their results on the memory tests.
The best part is, those changes in white matter volume and function, the strengthening of our myelinated axon neurological pathways, were measurably impacted by just 120 minutes of regular, moderately intense physical exercise. Few things are more enjoyable than a brisk walk on a cool winter day. You can be your own judge on line dancing.
We’re fortunate in Pelham to have good sidewalk snow clearing combined with low-traffic roads and streets to walk on even during our short snow season. Snow and ice traction cleats are inexpensive and add considerably to the safety of winter walking. Worst case, walk indoors at the MCC track, join a gym or the YMCA, or purchase a treadmill.
The withered leaves and morning frost on our car windshields signify winter is approaching, but hibernation is for bears and chipmunks. I’ll certainly catch up on my reading, and may even learn what Netflix is all about (actually, I doubt that), but winter won’t stop me from working on my at-risk grey and white matter volume. Seems like such an easy choice. ◆