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more photosSuzi MacLeod, 75, runs downstream on the Deschutes River Trail from Meadow Camp toward Bend with her 6-year-old dog, Georgie. MacLeod recently participated in a study that looked at the effects of exercise on brain function.
Andy Tullis/The Bulletin
Brain strength
New research may show that consistent exercising can reduce risk of dementia
By Betsy Q. Cliff / The Bulletin
Published: September 10. 2009 4:00AM PSTThis summer Suzi MacLeod set the record for the fastest mile ever by a 75- to 79-year-old, completing the distance in 8 minutes, 16.3 seconds.
That wasn't her only accomplishment. The 75-year-old Bend woman also traveled in June to Dallas where she participated in research that could show why exercise can stave off dementia.
Researchers at the University of Texas Southwestern Medical Center capitalized on MacLeod's lifelong dedication to exercise to look at whether her body and brain looked different than a person who was more sedentary.
Though the results will likely take several months to compile, the researchers are hopeful about finding differences that may explain why those who exercise seem to be protected from Alz-heimer's disease. Today, that disease affects more than 5 million Americans, and many more have milder forms of dementia.
The study MacLeod participated in builds on principles from several other lines of research. It first attempts to answer questions raised by previous studies on exercise and brain function. Second, the research hopes to build on previous findings related to declines in the cardiovascular system.
Fit body, fit mind
Today, there's good evidence that maintaining an exercise routine is crucial as people age. It is important not only for maintaining a fit body but also a fit mind.
The Texas study built on previous research showing that people who exercise more do better on cognitive tests and have a lower risk of dementia.
One major study, published in 2006, followed about 1,700 people ages 65 and older for six years, measuring how often they exercised and how sharp their brains were.
The researchers found that people who exercised at least three times a week were 30 to 40 percent less likely to develop dementia than those who did not.
Dr. Eric Larson, who led the study and who directs the Group Health Center for Health Studies, said his study and others make a convincing argument that exercise can benefit older brains.
Larson said that he recommends exercise, even in small doses, to older people to prevent dementia. “My own belief is that a very modest amount goes a long way. You just have to get over a certain level.”
Larson said that three or four days a week of 30- to 45-minute sessions, can help to decrease a person's risk of mental decline.
A more recent study, published in 2008, confirmed Larson's findings. That study looked at people at high risk for cognitive decline, some of whom said they already had memory problems. About half were enrolled in a six-month exercise program, which involved three 50-minute exercise sessions each week. At the end of the study, everyone took another cognitive test, and those who exercised were compared with those who did not.
The group that exercised improved their scores on cognitive tests while those in the sedentary group did not. Impressively, exercise improved the scores more than a common drug taken to slow the progression of dementia.
Those in the field say these studies and others provide fairly clear evidence that exercise prevents dementia. Still, there are many unknowns. Key among those is why exercise might benefit the brains of the elderly.
That's what MacLeod headed to Dallas to help answer.
Study days
This was not the first time MacLeod had been to Dallas. She grew up in Ketchum, Idaho, and began running more than three decades ago when she was in her mid-40s. At that time, she was living near Ketchum and running was not yet popular. People often stopped to ask her if she needed a ride.
Her first year, she competed in a marathon, she said, and has not stopped running since. She said running added a vividness to her life that mimicked the switch from black-and-white television to color. Before running, “I had a really good life,” she said. “When I ran, it was like color TV. My world was that much changed.”
During her first trip to Dallas several years ago, she was involved in a cardiovascular study that looked at how the hearts of lifelong athletes compared with the hearts of sedentary people.
That study, led by Dr. Benjamin Levine, focused on what caused heart problems in old age that might lead to heart failure and whether exercise could alleviate those problems.
Levine's study sought to explain the tightening of the heart muscle and circulatory system as people age. In the same way that other areas of the body tighten - such as the skin becoming less supple - the blood vessels also tighten. Levine wanted to see if, in the heart, this was an inevitable consequence of aging or if exercise could prevent it.
What Levine and his team found was that exercise almost entirely prevented a decline in the heart typically seen in aging. “Suzi's heart was indistinguishable from a typical 30-year-old,” said Levine. “Training at that level completely prevents tightening of the heart.”
She had returned to Dallas to see if the same principle applied to her brain.
Answering the ‘why'
There is some evidence, Levine said, that the same tightening that occurs in an aging heart could also happen in a brain. The blood vessels that supply brain cells with oxygen and other nutrients may tighten up, leading to the loss of brain cells, a primary cause of dementia.
Brain cells “need a constant supply of blood flow,” said Rong Zhang, a physiologist who is leading the current study MacLeod participated in. Because exercise seems to improve the blood flow in other areas of the body, namely the heart, Zhang wants to look at whether it will also improve blood flow to the brain, which could prevent atrophy and perhaps the mental decline seen in Alzheimer's disease or other forms of dementia.
To help him answer that question, MacLeod spent two days in Dallas, going from test to test as she completed the study protocol. On the first day, she spent five hours in an MRI scanning machine, two hours as part of a brain scan study and another two hours looking at her cardiovascular system. She had her breathing tested to see how well her body processed oxygen. She ran on a treadmill to find her maximum heart rate.
The second day, she went through a battery of cognitive tests to assess how sharp she was compared with others her age. One test featured a series of color words: red, green, blue and so on, written in different colors. The task was to name the color of the ink rather than reading the word. So if “red” was written in green ink, MacLeod should say “green.”
It was difficult, she said. “My 75-year-old brain had to adjust to a new concept.”
The results are not in yet. It will likely be several months before they are fully analyzed, and it could be up to a year or more before those results are published.
Still, it could help researchers figure out why some people's minds decline faster than others. Furthermore, it could unite the results of varied lines of research, helping to explain the process of aging and how exercise can help slow that process.
“This is a very novel concept,” said Zhang. “There are no data right now.”
Betsy Q. Cliff can be reached at 541-383-0375 or bcliff@bendbulletin.com.
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