Published on: May 4, 2014
by Women’s Brain Health Initiative:
At this point in the time, “there is no silver bullet, no pharmacological intervention that has been proven successful at reversing or preventing Alzheimer’s disease,” explains Marc Poulin, member of the Hotchkiss Brain Institute and Brenda Strafford Foundation Chair in Alzheimer Research within the Faculty of Medicine at the University of Calgary.
Lifestyle choices, however, are known to impact the risk of getting Alzheimer’s disease and the rate of the disease’s progression.
A 2010 report released by the Alzheimer Society of Canada, Rising Tide: The Impact of Dementia on Canadian Society, warns of a coming dementia epidemic. At the time the report came out, approximately 500,000 Canadians had dementia, and that number is expected to rise to over 1.1 million within a generation (by 2038) – that will be 2.8 percent of the Canadian population!
The cost in 2010 of dementia care was $15 billion, and that cost is expected to balloon to $153 billion by 2038. And what about the caregivers? How much time do Canadians spend providing informal care for loved ones with Alzheimer’s disease or a related dementia? In 2010, Canadians were already spending 231 million hours providing informal care and by 2038 that is predicted to grow to 756 million hours. The cumulative economic burden is expected to reach $872 billion by 2038, while the demand for long-term care will increase 10-fold.
A study published by Lancet Neurology in 2011 calculated the number of cases of Alzheimer’s disease that could be attributed to potentially modifiable risk factors including diabetes, midlife hypertension, midlife obesity, depression, physical inactivity, smoking and low education. Physical inactivity had the second highest level of relative risk, after depression. Poulin focuses on researching the impact of increasing physical activity levels on brain function.
Cognition Clearly Boosted by Exercise
A strong relationship exists between physical activity and cognitive performance; that has been well established through more than 30 years of research. While research has clearly shown that physical activity has a favourable effect on cognition in older populations, what remains unclear is what the underlying mechanisms are for that positive effect. Are the improvements in cognition caused by changes in blood flow to the brain? Poulin believes so. He has led studies examining whether greater amounts of blood circulating to the brain helps explain the boost in cognitive performance observed with aerobic exercise.
One study set out to test the hypothesis that post-menopausal women who exercise will have better cognitive outcomes than post-menopausal women who are sedentary. Forty-two women in Calgary, aged 50 to 90 years, were recruited – half of which were considered sedentary and half of which were considered active and fit, based on their self-reported activity levels and a stress test to measure their fitness.
After administering a comprehensive set of cognitive function tests, an overall average cognition value (or score) was calculated for each participant. The average cognition value for the active and fit group as a whole was 10 percent higher than for the sedentary group, indicating that the active group seemed to have better cognitive function overall.
Participants also underwent numerous other tests related to their cardiorespiratory function and cerebral blood flow, and the results showed that with exercise you bring about great benefits to the blood vessels in your brain, which helps increase cognitive performance. Poulin believes that improved cerebral blood flow helps bring nutrients to the brain and remove waste products of metabolism from the brain, both important for brain health.
Intervention Explores Impact of Exercise on Blood Flow in Brain
To expand on what was learned in that initial study of older women, Poulin is now leading another study, Brain in Motion, that is examining the impact of introducing structured aerobic exercise to a group of sedentary men and women over the age of 55. The 250 dedicated participants will do aerobic activity for 30 minutes per day, four days each week, for a six-month period, while tracking their progress using a wide range of tests, to assess what is happening to their bodies and brains as a result of this physical activity intervention.
The first batch of participants started in 2010 and the last batch will finish this year. Once each group has finished their six-month session of structured training, they will return for additional testing six months later to determine the extent to which changes persist over time. Initial results suggest that participants are significantly increasing their aerobic fitness levels and experiencing improvements on cognition tests. Tests also show that the volume of blood flowing to their brains is increasing modestly. Anecdotal findings are strong, as well, with many participants reporting that they are noticing improvements in their cognition, sleep and energy levels. Complete study results will be available in 2015 and will include an analysis of sex differences.
Introducing regular aerobic exercise has proven to be a powerful intervention, one that is inexpensive and easily accessible to most people. It is widely understood that exercise offers powerful benefits for the heart and body, and now Poulin’s research has helped contribute to our understanding of its impact on brain health as well. Future research is likely to strengthen the already strong case in favour of getting active.
Start Exercising Today
The onset of Alzheimer’s disease is a gradual process, with a lag occurring between the time initial biomarkers of the disease show up in the body and the time clinical symptoms are noticeable. That lag phase varies in length from person to person, typically lasting between 10 and 20 years before the disease becomes evident. That leaves a big window of opportunity to try and intervene, making lifestyle changes that can possibly prevent or slow down the progression of cognitive decline. As Poulin points out, “It’s never too late to start making healthier lifestyle choices. Today’s a great day to begin.”
 If you have any health concerns, it is recommended that you see your doctor before starting an exercise program.
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