07/21/2014 05:34 pm ET | Updated Sep 20, 2014

Action Is the Key in Alzheimer's Prevention

If you watch the news long enough, we physicians seem to reverse our advice every 10-15 years. Examples include whether butter or margarine is better and whether you should take aspirin to prevent strokes. A conservative approach to your health may therefore entail waiting to see which recommendations stand the test of time.

A time-tested, multiply replicated recommendation for prevention of Alzheimer's disease is participation, as early in life as possible, in physical activity. Note, I am not writing "rigorous exercise" here, as we mean to include those folks who may be limited in their mobility (by osteoarthritis) but who are not sedentary couch potatoes. If you search the commonly-used database for medical journal articles, PubMed, for articles linking physical activity to dementia, you'll get nearly 3,000 hits from recent years. The effect of physical activity on lowering risk for dementia is much more impressive than that of any drug or neutraceutical, so why not get onto this bandwagon ASAP? (1-7) Some evidence indicates that getting started in your teens helps seal that preventative deal.

How does it work?

The benefits of regular exercise for the brain are adding up all the time:

1) Keeps your body mass index low (fights obesity).
2) Reduces stroke risk and possibly eradicates that particular dementia risk factor.
3) Reduces stress (provided you pick the right activities for your body and personality).
4) Racks up plasticity points through learning new skills.
5) Creates a social outlet to decrease times of loneliness, which is itself a risk for Alzheimer's disease.
6) Potentially reducing risk of falls, which figures large in quality of life and mortality for the elderly. Falling and breaking a hip leads to major immobility and therefore is a huge mortality risk factor for an elderly person.

Driving the body more efficiently relates directly to oxygen consumption, and we now know that a body that consumes oxygen very efficiently is usually attached to a brain that is fairly resilient to the downsides of aging, as well. Doing more with less (oxygen) seems to be an advantage, no matter what bodily function you consider. (8)

When you exercise, there actually is a positive change in the size of brain areas related to increased activity. Studies have shown that mastering a new motor task, like juggling, leads to structural changes in the brain cells. The areas that control your hands and arms and eyes increase in size. (9) We have been scrambling to see if the same effect holds true if you "exercise" the parts of your brain that carry out cognitive functions, such as naming things, or remembering new information.

How might exercise help to maintain your intelligence or your ability to retain incoming information? The more new skills you attain, the more opportunities there are for cross-referencing information and greasing up neuronal access to that movement or that cognitive strategy. It seems to work in both the physical realm and in the higher cognitive one.

Rigorous exercise (and wise dietary choices) can put you into the right body mass index (BMI) range for your age and build. Having a high BMI (over 25) in mid-life leads to earlier brain volume loss in late-life than normal range BMI. (10) Elevated BMI can also contribute negatively to stress hormone risks for dementia. (11) Once we have a better understanding of BMI and Metabolic Syndrome, we might be able to hone the advice we give on when it is most important to start exercising, if it's not already part of your routine and how long you must keep it up to see benefits.

In the meantime, devising an ideal exercise program may be as complicated as individual dietary choices. If your activities are compromising your sense of safety, happiness, and health, it's time to consider a change. I gave up underwater hockey and kickboxing, because there was too much bruising in those contact sports for me. I was in top cardio fitness condition, but I wasn't nimble enough with my swim fins to avoid getting kicked in the head, and I quit shortly after one game during which the team captain noticed I'd stopped moving in the water. He literally threw me out of the pool onto the side where I came to! (Thanks, Cid.) Participation in a sport that gives you "drain blamage" rates re-evaluation.

Certain activities may yield more of a social benefit for some people than a physiological one. Going for a brisk walk is not without its dangers (watch out for cars and uneven ground!), but it's something you can easily recruit friends to. Right now, we don't know which is more beneficial to your brain in the long run, but I repeat that if your exercise plan allows you enjoyment, a sense of well-being, and doesn't impinge on your safety, it's probably a good thing in your life.

Patients with dementia can and should remain physically active in sports they had previously mastered. They may not be as accurate in keeping score as before, but if the dementia has not carved away their motivation to pursue the activity, it can bring all the same benefits as before. The effects of physical activity have shown more robust effects on keeping people's cognition and mood intact than any medication trials thus far!

There have been unequivocal findings in favor of maintaining as physically active a lifestyle as possible from your earliest years to your latest ones. Studies on frail elders not only correlate frailty to enhanced morbidity with dementia and hastened mortality, they also show the impacts of nutritional, physical activities, leisure activities, and health-related behaviors (engagement with others, regular screening at the doctor's office, compliance with medications) on the degree of frailty you exhibit. (12) But exercise training can be done creatively for those who are frail. Watch Dr. Louis Bherer's work at the University of Quebec at Montreal (UQAM) for positive results from his studies comparing the frail elderly to patients with mild cognitive impairment.


(1) Baker, L. D., et al. "Effects of aerobic exercise on mild cognitive impairment: A controlled trial." Archives of Neurology 67(1) (2010): 71-9.

(2) Berchtold, N. C., et al. "Exercise primes a molecular memory for brain-derived neurotrophic factor protein induction in the rat hippocampus." Neuroscience 133(3) (2005): 853-61.

(3) Buchman A. S., et al. "Total daily physical activity and the risk of AD and cognitive decline in older adults." Neurology 78(17) (2012, Apr. 24): 1323-9.

(4) Langlois, F., et al. "The benefits of physical exercise training on cognition and quality of life in frail older adults." Journal of Gerontology: Psychological Sciences, 68 (3) (2013): 400-404

(5) Larson, E. B., et al. "Exercise is associated with reduced risk for incident dementia among persons 65 years of age and older." Annals of Internal Medicine 144(2) (2006): 73-81.

(6) Maesako, M., et al. "Exercise is more effective than diet control in preventing high fat diet-induced beta-amyloid deposition and memory deficit in amyloid precursor protein transgenic mice." Journal of Biological Chemistry 287(27) (2012): 23024-33.

(7) Renaud, M., F. Maquestiaux, S. Joncas, M. J. Kergoat, and L. Bherer. "The effect of three months of aerobic training on response preparation in older adults." Frontiers in Aging Neuroscience 2 (2010): 148.

(8) Shah, R. C., A. S. Buchman, R. S. Wilson, S. E. Leurgans, and D. A. Bennett. "Hemoglobin level in older persons and incident Alzheimer disease: Prospective cohort analysis." Neurology 77, no. 3 (2011): 219-26.

(9) B. Draganski, V. Busch, G. Schuierer, U. Bogdahn, A. May. "Changes in grey matter induced by training newly honed juggling skills show up as a transient feature on a brain-imaging scan." Nature, 427 (2004), pp. 311-312 AND P. Gerbera, L. Schlaffkeb, S. Hebab, M.W. Greenleec, T. Schultzd, T. Schmidt-Wilckeb. "Juggling revisited -- A voxel-based morphometry study with expert jugglers." NeuroImage 2014; 95: 320-325.

(10) Soreca I, Rosano C, Jennings JR, Sheu LK, Kuller LH, Matthews KA, Aizenstein HJ, Gianaros PJ. "Gain in adiposity across 15 years is associated with reduced gray matter volume in healthy women." Psychosom Med. 2009 Jun;71(5):485-90.

(11) Willette AA, Kapogiannis D. Does the brain shrink as the waist expands?" Ageing Res Rev. 2014 Apr 22. pii: S1568-1637(14)00044-0. doi: 10.1016/j.arr.2014.03.007. [Epub ahead of print]

(12) Song, X., A. Mitnitski, and K. Rockwood. "Nontraditional Risk Factors Combine to Predict Alzheimer Disease and Dementia." Neurology 77, no. 3 (2011): 227-34.

Excerpted from The Memory Clinic

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