From The Desk Of Clarence Bass
Aerobics may be a smart workout for your brain at any age: Science Daily (May 13, 2020)
Brain Function Improved after Only Six Months of Exercise
Impact of Exercise on the Brain
A study published online May 13, 2020, in the journal Neurology found that 206 low-active adults, mean age 66, improved by 5.7% on thinking and memory tests after only six months of submaximal aerobic exercise three or four days a week.
"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," study author Marc J. Poulin, Ph.D., D.Phil., from the Cumming School of Medicine at the University of Calgary in Alberta, Canada, told Science Daily. "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."
Increase in blood flow to the brain was a key finding, indicating that aerobic exercise reaches all parts of the body, including the brain—at a time when mental function is often in decline.
Using ultrasound, peak blood flow was found to rise from an average of 51.3 centimeters per second to an average of 52.7, a 2.8% increase.
Poulin termed these findings, “exciting.”
Exercise which improves cardiovascular function may extend to the brain and be a potential mechanism to treat or slow the exponential rise of Alzheimer's disease and other forms of dementia.
We also have a comprehensive Review (Exercise Improves Vascular Function, but does this Translate to the Brain?) evaluating the role of exercise in improving cerebral circulation, cognition, and brain health.
We’ll cherry pick from a few sections, and then point you to the entire Review online. It’s Open Access.
PHYSICAL ACTIVITY, FITNESS AND COGNITION
Lifelong physical activity and high levels of cardiorespiratory fitness are important for brain health as we age.
In a recent study, higher cardiorespiratory fitness in women at midlife was associated with lower risk of dementia approximately 44 years later. In addition, greater cardiorespiratory fitness levels at age 18 were associated with a lower hazard ratio for development of mild cognitive impairment or dementia. Taken together, these results suggest that cardiorespiratory fitness and lifestyle behaviors during the young and middle-aged years are important in determining future risk of cognitive decline.
Another factor that could explain some of the beneficial effects of regular exercise on cognition is the maintenance of cerebral blood flow (CBF). In older adults, there is a positive association between self-reported volumes of physical activity and CBF in grey matter regions.
While physical activity recall, physical activity tracking (e.g. steps per day using physical activity trackers), and cardiorespiratory fitness (VO2max) are used in quantifying physical activity and exercise, the mechanisms underlying the cognitive effects of physical activity vs. fitness may be different…Taken together, these results suggest that interventions designed to increase cardiorespiratory fitness, rather than simply increasing physical activity volumes or reducing sedentary behavior, may offer the greatest neuroprotection in middle-aged and older adults.
One of the hallmarks of regular endurance exercise and endurance exercise training in previously sedentary individuals is enhanced cardiovascular function. Enhanced cardiovascular function is associated with a range of benefits to many organ systems and it is likely that the cardiovascular adaptations associated with exercise also influence brain health. Therefore, the enhancement in cardiovascular function may mediate the relationship between fitness, brain structure, cerebral blood flow and cognition.
ADDITIONAL MECHANISMS UNDERLYING THE BENEFIT OF EXERCISE
This review discussed the hypothesis that improved vascular health is one mechanism underlying the association between regular aerobic exercise and enhanced cognitive function.
In addition to improvements in vascular health, regular aerobic exercise induces numerous cardiac, musculoskeletal, and metabolic adaptations that may also contribute to the brain. A consistent finding is that exercise can induce [growth and survival factors], such as vascular endothelial growth factor (VEGF) or brain-derived neurotrophic factor (BDNF), but the mechanism by which these are activated and affect the cerebral circulation are less clear. During exercise, skeletal muscle contraction causes the release of numerous biologically-active factors into the circulation. These “myokines” can then affect other tissues through [cell signaling] mechanisms that may mediate the systemic effects of regular exercise. These myokines may also promote [the growth and development of nervous tissue], linking skeletal muscle contraction to brain structure and function.
During high-intensity exercise, [lactic acid] accumulates in the skeletal muscle and blood lactate concentrations increase. Thus, studies have investigated lactate as a potential link between skeletal muscle contraction and brain adaptations. High-intensity exercise in mice, sufficient to elevate blood lactate levels, [stimulates the formation of blood vessels]. Lactate injection has been shown to mimic the effect of exercise and increase BDNF concentration in humans. Along these lines, exercise at a high enough intensity to promote lactate production in humans is associated with improved motor memory and executive function. Taken together, these studies demonstrate that numerous byproducts of skeletal muscle contraction may contribute to neurogenesis, cerebral angiogenesis, and enhanced brain function, if the exercise is of sufficient intensity and repeated regularly.
[Sounds like resistance training may have a role in improving brain function. A new study in the Journal of Applied Physiology suggests that may indeed be the case. Using rats, researchers demonstrated that weight training can overcome cognitive impairment and even jumpstart the creation of new neurons. Just three resistance-training “workouts” a week were enough to improve cognition and boost memory performance. A very interesting study, we’ll have more about it in our next update.]
Advancing age is the largest risk factor for developing Alzheimer's disease or other dementias. The epidemiological and experimental evidence strongly suggests that cardiovascular risk factors and/or poor vascular health is positively associated with cognitive decline. As blood vessel health is associated with both brain structure and brain function, vascular health is likely a key mechanism by which regular aerobic exercise improves cognitive function. The World Health Organization estimates that 25% of adults, globally, are not meeting the minimum physical activity recommendations. The high percentage of adults who are physically inactive will have a substantial impact on future brain health. Importantly, higher volumes of exercise and greater cardiorespiratory fitness are associated with favorable vascular function and the majority of studies show that aerobic exercise interventions improve vascular function in healthy adults. Aerobic exercise could directly increase [the development of new blood vessels in the brain], preserve the function of existing cerebral microvessels, or enhance extracranial artery function to protect the cerebral microvasculature from the unfavorable [dynamics of blood flow]. Because direct evidence on the effect of exercise on cerebrovascular function in humans is currently limited, future studies are necessary to determine the effect of aerobic exercise on cerebrovascular function and elucidate the potential underlying mechanisms. Furthermore, additional research is necessary to optimize and implement exercise interventions early in the treatment or prevention of cognitive decline.
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The above is an overview, a synopsis. To read the entire Review:
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I’ve long believed that exercise is good for the brain. What’s good for the heart is also good for the brain. The evidence has piled up with the passage of time.
My success in high school sports and on the Olympic lifting platform gave me the work ethic and can-do attitude that allowed me to succeed beyond expectations in law school.
Training for the Pentathlon and wrestling in high school developed my cardiovascular fitness, but it wasn’t until I read Dr. Kenneth Cooper’s book Aerobics in my late 20s that I came to appreciate the health benefits of aerobic conditioning. (Dr. Cooper didn’t share my enthusiasm for lifting weights until years later.)
I’ve continued doing some form of aerobic exercise since then.
The foothills above our home offer aerobic challenges of all kinds.
Photo by Guy Appelman
At 50, I surprised people at the Cooper Clinic by staying on the treadmill almost two minutes longer than 99% of men my age. I believe I was the first weight lifter they had seen do well; weight trainers weren't expected to be aerobically fit. Muscles were looked on as a detriment.
I was, of course, demonstrating the benefits of combining strength and aerobic exercise. Two ends of a single continuum. You can't have one without some of the other.
As researchers are now finding, what’s good for the cardiovascular system is also good for the brain. There is no consensus that a combination of strength and aerobic training does that best, but we appear to be heading in that direction.
June 1, 2020
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