Rong Zhang — 80% Mental Blog — 80 Percent Mental

There was a time when I could hide my gray hairs with some strategic combing. Now, I have succumbed and describe my new hair color as “executive blond.” Of course, that also means that the important stuff under my scalp is getting older too. Brains start to “go gray” about the same time the hair does, which is why exercise for older adults has become the new anti-aging fix for our senior cerebellums. Several new studies provide more evidence that a brain in motion tends to remain... young.

The older population (which does not include me yet!), persons 65 years or older, totaled 39.6 million in 2009 (the latest year for which data is available). They represented 12.9% of the U.S. population, about one in every eight Americans. By 2030, there will be about 72.1 million older persons, more than twice their number in 2000. People 65+ represented 12.4% of the population in the year 2000 but are expected to grow to be 19% of the population by 2030.

Over the last several years, dozens of studies have concluded that exercise helps not only your reflection in the mirror but also your cognitive ability. Just in the last four months, three research projects, one small, one medium and one large, reported their findings of the effects of exercise on the older brain.

First up, a micro study of 16 women, aged 60 and over, hypothesized that a moderate exercise program would increase blood flow to the brain. Dr. Rong Zhang, a researcher at the Institute for Exercise and Environmental Medicine at Texas Health Presbyterian Hospital Dallas, first measured the blood flow in the women's internal carotid arteries, using Doppler ultrasonography. Next, a baseline test was taken of their maximal oxygen consumption (VO2 max) to gauge their body’s ability to use oxygen during exercise.

Then the walking started. Each woman was given a training plan based on their current fitness level that started with three 30-minute sessions per week of walking at a pace of 50-60% of their VO2 maximum. By the third month, this was increased to four sessions at 70-80% of VO2 max.

A second blood flow test showed a significant increase in cerebral blood flow by an average of 15% in the women’s left carotid artery and 11% in the right artery. VO2 max also went up by 13%, while their blood pressures and heart rates declined by 4% and 5%, respectively.

Dr. Zhang likes the correlation, "There are many studies that suggest that exercise improves brain function in older adults, but we don't know exactly why the brain improves. Our study indicates it might be tied to an improvement in the supply of blood flow to the brain."

So, what might that extra blood be doing for the brain? Kirk Erickson, professor of psychology at the University of Pittsburgh, is convinced that exercise actually grows the size of the brain. He and a cross-university team of scientists recruited 120 dementia-free, sedentary senior citizens to measure their brain size before and after a one year long walking program. After measuring each volunteers’ hippocampus dimensions using magnetic resonance imaging (MRI), they were split into two groups. One group would start a walking program of 40 minutes per session, three days per week, while the other group simply did a stretching and toning program.

After one year, a second MRI showed that the walkers increased their hippocampus size by an average of 2% while those that only stretched showed a decrease in brain volume of about 1.4%. Also, a spatial memory test performed pre and post exercise showed a significant improvement for the walkers versus the stretchers.

"We think of the atrophy of the hippocampus in later life as almost inevitable," said Kirk Erickson, professor of psychology at the University of Pittsburgh and the paper's lead author. "But we've shown that even moderate exercise for one year can increase the size of that structure. The brain at that stage remains modifiable."

There is another important benefit to that extra blood flow, preventing strokes or even small brain lesions, or infarcts, often known as silent strokes. "These 'silent strokes' are more significant than the name implies, because they have been associated with an increased risk of falls and impaired mobility, memory problems and even dementia, as well as stroke," said brain researcher Joshua Z. Willey, MD of Columbia University in New York.

Willey and his team asked 1,238 people over age 60, who had never had a stroke, about the frequency and intensity of their exercise regimen. About 43 percent of the participants reported that they had no regular exercise; 36 percent did regular light exercise, such as golf, walking, bowling or dancing; and 21 percent performed regular moderate to intense exercise, such as hiking, tennis, swimming, biking, jogging or racquetball.

Six years later, all participants underwent an MRI scan of their brain. Sixteen percent of the group, 197 volunteers, had suffered from an infarct or silent stroke during the time frame. However, the moderate to intense exercise group was 40% less likely to have had the small lesions than the group that did not exercise at all. There was no significant difference between those that did light exercise and those that did no exercise.

"Encouraging older people to take part in moderate to intense exercise may be an important strategy for keeping their brains healthy,” concluded Willey. "Of course, light exercise has many other beneficial effects, and these results should not discourage people from doing light exercise."

So, no excuses anymore. Throw some hair color on your scalp, then go for that walk. Your hair will look young and your brain will think young.

See also: Exercise Pumps Up Your Brain and Boomer Brains Need Exercise

Research conducted at Texas Health Presbyterian Hospital's Institute for Exercise and Environmental Medicine in Dallas suggests that it's never too late for women to reap the benefits of moderate aerobic exercise. In a 3-month study of 16 women age 60 and older, brisk walking for 30-50 minutes three or four times per week improved blood flow through to the brain as much as 15%.

Rong Zhang, the lead researcher in the study, discussed the team's findings in a presentation titled, "Aerobic exercise training increases brain perfusion in elderly women" at the Experimental Biology meeting (EB 2011), held April 9-13, 2011 at the Walter E. Washington Convention Center, Washington, DC.

At the beginning of the study, the researchers used Doppler ultrasonography to measure blood flow in the women's internal carotid arteries, which are located in the neck and supply the brain with necessary glucose and oxygen-rich blood. After assessing the women's physical health and maximal oxygen consumption (VO2 max), which is the body's maximum capacity to transport and use oxygen during exercise, the team tailored training programs for each woman according to her fitness level.

Training started at a base pace of 50-60% of the participants' VO2 max for 30 minutes per session, three times per week. By the third month, the team had increased the sessions to 50 minutes each, four times per week, and added two more sessions at 70-80% of the women's VO2 max for 30 minutes.

At study's end, the team measured blood flow in the women's carotid arteries again and found that cerebral blood flow increased an average of 15% and 11% in the women's left and right internal carotid arteries, respectively. The women's VO2 max increased roughly 13%, their blood pressure dropped an average of 4%, and their heart rates decreased approximately 5%.

According to Dr. Zhang, the results provide insight into how vascular health affects brain health. "There are many studies that suggest that exercise improves brain function in older adults, but we don't know exactly why the brain improves. Our study indicates it might be tied to an improvement in the supply of blood flow to the brain."

A steady, healthy flow of blood to the brain achieves two things. First, the blood brings oxygen, glucose and other nutrients to the brain, which are vital for the brain's health. Second, the blood washes away brain metabolic wastes such as amyloid-beta protein released into the brain's blood vessels. Amyloid-beta protein has been implicated in the development of Alzheimer's disease.

Whether the increased blood flow to the brain improves learning and reasoning has yet to be determined, says Dr. Zhang. "I don't have the data to suggest a correlation between brain perfusion and cognitive function, but this is something we eventually will see after this study is completed," he says. "We do know there is strong evidence to suggest that cardiovascular risk is tied to the risk for Alzheimer's disease. We want to see how we can fight that."

Dr. Zhang stresses the importance of the finding that improvement in brain blood flow is possible in one's senior years. "We often start to see a decline in brain perfusion and cognitive function in the 60s and 70s. That's when the downward trajectory starts. We want to see how much we can do to reverse or delay that process."

Source: American Physiological Society

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