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It's no secret. I worry more about the health of my brain than that of my heart. And so do plenty of others.
Both my parents had strokes. I'd be a fool not to worry. My dad had a massive global stroke at age 69--and lived for 16 years without being able to talk, read his beloved New York Times, listen to his favorite radio stations, or understand what anyone was saying to him. Eventually, he could no longer walk, feed himself, or swallow.
My mom experienced slow insidious imperceptible tiny strokes in her seventies (perhaps before), along with coronary heart disease, and that finally progressed into vascular dementia during the last years of her life.
If you think strokes, cognitive impairment, or dementia aren't something you need to worry about, you better think again.
Cognitive Impairment, the REGARDS Study & the Case of the Undiagnosed Teeny-Weeny Stroke
The newly published-ahead-of-print REGARDS study found cognitive impairment developed in over 8% of Americans age 45 or over (the mean age was 64) who were followed for a period of 4 years, and were free of any strokes or cognitive impairments at the study's start.
24,000 people participated in this large study--representative of the broad demographics of the entire U.S.--and all were free of cognitive impairments or dementia when the study began.
The purpose of the study was to determine if the cognitive impairments of aging were higher in the South--mirroring the higher incidence of stroke mortality in that region. And yes, the South had a higher incidence of cognitive impairment, compared to the rest of the county--clocking in at 8.2%.
In spite of the small numerical differences between the South & the rest of the country (8% vs 8.2%), the experts all agree that this difference is larger than the numbers imply--with Southerners 18% more likely to show cognitive impairment.
The authors, along with neurology experts have suggested that the subtle cognitive impairments seen in the REGARDS Study participants were likely caused by small, undetectable strokes that subtly affected brain function.
The "brain-damaging suspects" are likely to be the much-loved traditional Southern diet of fried, salty, & fatty foods along with too little exercise--all of which contribute to hypertension, excess weight, & diabetes--the biggies responsible for stroke risk.
- Wadley, VG et al. "Incident cognitive impairment is elevated in the stroke belt: The REGARDS Study," 2011 Annals of Neurology published online ahead of print on May 26. doi: 10.1002/ana.22432. [Epub ahead of print]
"This is a very strong alarm signal. [The finding suggests that] if you want to keep your marbles, you need to control your blood pressure, excessive weight and other risk factors for stroke."
Dr. Gustavo C. Roman, the head of the neuroepidemiology section of the American Academy of Neurology, commenting on the article.
[Problems like high blood pressure and diabetes are likely to be "affecting blood flow to the brain, even if it's not causing a visible stroke. An undersupply of blood can also cause problems with brain cells that lead to cognitive decline."
Dr. Kenneth Langa, a professor of Internal Medicine at the University of Michigan, commenting on the article.
The "Silent Stroke"-Cognitive Impairment Connection Isn't a New Story
Dr. Megan C. Leary of UCLA examined over 5,500 MRIs of the brains of 50 year olds & found many had tiny white spots that indicated that they had unknowingly experienced tiny, imperceptible strokes. These "brain attacks" have the same history and cause as heart attacks. See "Annual Incidence of First Silent Stroke in the U.S" Cerebrovasc Dis 2003;16(3):280-5.
According to Leary, "'Silent strokes' are epidemic in this country. While they occur in parts of the brain where they don't cause symptoms right away, the word 'silent' should be put in quotes, because their effects accumulate over the years.'' Read more here.
I've been betting my "brain ranch" since age 30, on the hopes that regular exercise will help protect my brain. At the very least it boosts my mood (& as you'll soon find out, that's a good thing, because depression is also a risk factor for Alzheimer's)--and it makes me feel strong & fit. These days, exercise for me means: indoor spinning, strength training, yoga, walking/hiking, and occasional outdoor cycling.
OK--truth be told--I'm not only betting my "brain ranch" on exercise--I'm hedging my bets by also eating a no-oil plant-based diet! And I try to throw in a hefty side of keeping down the stress--and getting enough sleep. I'm not a risk-taker!
OK. Finally. The Main Point of This Post.
It's Exercise!!! The Big News in Dementia/Alzheimer's Prevention
So, last week when I read the press releases from the 2011 Alzheimer's Association International Conference , held in Paris, July 16-21, I was very encouraged. Really encouraged.
Maybe my exercise investment will pay off, yet!
Two of the four articles I'm highlighting in today's post, were not only presented at the Alzheimer's Association conference--but they were simultaneously published in top-notch medical journals. That means they're really big well-documented studies! They also drew a lot of media attention.
We all want to know what we can do to protect our brains--because currently there's no prescription drug or vaccine that will do that for us. Prevention is all we've got. So, here are the latest research studies to help convince us that exercise isn't optional--that is, if we want to make sure our brains last as long as our bodies.
- Vercambre, MN et al. "Physical Activity and Cognition in Women with Vascular Conditions," Arch Intern Med 171(14):1244-1250, July 25, 2011 Read more here. Also presented at the AAIC conference.
- Middleton, LE et al. "Activity Energy Expenditure and Incident Cognitive Impairment in Older Adults," Arch Intern Med 171(14):1251-57, July 25, 2011 Read more here.
- Larson, EB, "Brains & Aging," Arch Intern Med 171(14):1258-59, July 25, 2011. Larson's article was an Invited Commentary on Middleton's & Vercambre's research. Read more here.
- Barnes, DE & Yaffe, K. "The Projected Effect of Risk Factor Reduction on Alzheimer's Disease Prevalence," published ahead of print on July 19, 2011 in Lancet Neurology- Read more here. Also presented at the AAIC conference.
Look, the beneficial effects of exercise on the brain isn't "hot-off-the-press" news. There have been countless studies on the subject. So many in fact, that my favorite exercise scientist from the University of Illinois at Urbana-Champaign, Dr. Arthur F. Kramer, along with Michelle W. Voss, just published a monumental review article on the subject.
If you're interested in the benefits of exercise on the brain, be sure to read this one. It's free for the taking! Click here.
- Voss, MW , Kramer, AF et al "Exercise, Brain, and Cognition Across the Lifespan," Journal of Applied Physiology 2011 (ahead of print) Read more here.
What's the take home message of the following studies on the benefits of exercise for the prevention of cognitive impairment or Alzheimer's?
- Even adults with pre-existing cardiovascular disease or 3 or more risk factors for CVD can stall cognitive impairment with exercise. The more, the better. The study confirmed that higher levels of physical activity were consistently and significantly associated with less cognitive decline. (Vercambre study)
- In healthy adults, higher exercise activity levels may be protective against cognitive impairment in a dose-response manner. The more energy expended in exercise, the greater the cognitive benefits. This study used exacting techniques to measure energy expenditures--not just participant recall. (Middleton study)
- There are 7 risk factors for Alzheimer's that are modifiable & that we can control. We're not helpless against this disease. Up to half of the AD or dementia cases "are potentially attributable to these risk factors". Changing any of them can have a significant reduction on the incidence of Alzheimer's & cognitive impairment. In the U.S., exercise can make the greatest contribution, because it affects weight, diabetes, mid-life hypertension, & depression.
The Vercambre Study. It Analyzed the Effects of Exercise on Older Women at High Risk for Cognitive Impairment - Women with Pre-Existing Cardiovascular Disease or at High-Risk for CVD
"In summary, we found a clear and strong association between greater physical activity and reduced cognitive decline in our population of women with vascular disease or coronary risk factors. [Daily activity, at least a 30-minute daily walk at a brisk pace] appears to delay cognitive aging by 5 to 7 years." Dr. Marie-Noel Vercambre
"Based on our findings, we believe that moderate physical activity may be a very promising intervention for cognitive preservation, for both healthy aging populations and those at higher risk of cognitive impairment and dementia due to cardiovascular disease or risk factors." Dr. Jae Hee Kang, co-author
-Vercambre, MN et al. "Physical Activity and Cognition in Women with Vascular Conditions," Arch Intern Med 171(14):1244-1250, July 25, 2011-
The Middleton Study. It Used Exacting Techniques to Measure Exercise Energy Expenditure Among Healthy Seventy-Year Olds & Then Compared Exercise Levels to the Incidence of Cognitive Impairment
"The highest tertile (in the study) actually had a 90% reduction in the rate of incident cognitive impairment compared to the lowest tertile of activity energy expenditure.
"The mechanisms by which physical activity is related to late-life cognition are likely to be multifactorial.
Research suggests that physical activity may improve neuroplasticity by modifying levels of brain-derived neurotropic factor (BDNF).
Physical activity is also associated with reduced accumulation of beta-amyloid plaque--one of the hallmark features of Alzheimer disease--in animal models.
Finally, physical activity is associated with reduced rates and severity of vascular risk factors, including hypertension, obesity, and type 2 diabetes mellitus, each of which is associated with increased risk of cognitive impairment."
-Middleton, LE et al. "Activity Energy Expenditure and Incident Cognitive Impairment in Older Adults," Arch Intern Med 171(14):1251-57, July 25, 2011-
The Kramer & Voss Review Article. It Looks at the Effects of Exercise on the Brain & Cognition Across the Lifespan
"Specificially, aerobic training in late life preferentially benefits executive functions, including brain processes such as multi-tasking, planning, and inhibition, all largely supported by the prefrontal cortex.
There is growing evidence that both aerobic and resistance training are important for maintaining cognitive and brain health in old age. Our review also points out gaps in the literature and important future directions for the field."
Exercise appears to change brain structure, prompting the growth of new nerve cells and blood vessels. It also increases the production of neurochemicals, such as brain-derived neurotropic factor (BDNF) and IGF-1, that are responsible for the exercise-induced benefits on learning and memory, as well as promoting growth, differentiation, survival, and repair of brain cells.
"Thus, while all exercise might not be painless or provide the "easy fix" to enhance brain and cognition across the lifespan, there is ample evidence to support it is one of the the most effective means available to improve mental and physical health, without the side-effects of many pharmacological treatments."
-Voss, MW , Kramer, AF et al "Exercise, Brain, and Cognition Across the Lifespan," Journal of Applied Physiology 2011 (ahead of print)
The Barnes & Yaffe Study. It Used a Mathematical Model to Estimate the Effects of Seven Modifiable Risk Factors on Reducing Dementia, Cognitive Impairment & Alzheimer's
More than half of Alzheimer's cases globally could be prevented if modifiable risk factors such as depression, obesity, physical inactivity, midlife hypertension, diabetes, low educational attainment, and smoking were eliminated, either with lifestyle changes or treatment of underlying conditions, new research suggests.
In the United States, 21 percent of cases could be traced to low physical activity, 15 percent to depression, 11 percent to smoking, 8 percent to mid-life hypertension, 7 percent to mid-life obesity, 7 percent to low education and 3 percent to diabetes. (me: That comes to 72% by my calculations.)
According to the authors, "The largest proportion of Alzheimer's disease in the USA and a substantial proportion of cases worldwide were potentially attributable to physical inactivity." (me: Exercise can fix that!)
Because physical inactivity is associated with most of the other Alzheimer's disease risk factors identified--including depression, midlife obesity, midlife hypertension, and diabetes--public health initiatives to increase physical activity levels throughout life could potentially have a dramatic effect on Alzheimer's Disease and dementia prevalence over time.
Healthy circulation in the brain is thought to be key to keeping the mind sharp, and numerous studies have tied common heart risk factors, such as obesity or hypertension, to an increased risk for dementia. But the researchers stressed that the risk factors included in this analysis have not been shown to actually cause Alzheimer's, only to be associated with it.
-Barnes, DE & Yaffe, K. "The Projected Effect of Risk Factor Reduction on Alzheimer's Disease Prevalence," published ahead of print on July 19, 2011 in Lancet Neurology-
Want more evidence?
Read these four earlier posts for more motivation to get off the couch & exercise.
They convinced me to Increase my aerobic exercise--the better the cardiac index the less your brain's volume shrinks. What's good for the heart is unquestionably good for the brain, according to the latest Framingham study and a University of Pittsburgh study that demonstrated sizable increases in brain volume in the seniors who walked the most!
Mayo Clinic Researchers Discover the Nitric Oxide Connection to Brain Health, Alzheimer's, and Cognitive Impairment. Better Keep Your Endothelial Cells Healthy with Diet & Exercise
From the Archives of Internal Medicine--Seven Good Reasons to Exercise and Increase Your Chances For Healthy Aging
I'm hoping that Barnes, Yaffe, Kramer, Voss, Middleton, Larson, and all their predecessors are right!
Is anyone else pinning their brain health hopes on diet & exercise?
Got any success stories to share with us--and to motivate the rest of us?