Eventually, everyone experiences “senior moments.” You may forget where you left your keys, or walk into a room only to realize that you can’t recall why you entered in the first place. As we get older, the physical signs of slowing down also become increasingly apparent, whether it’s getting a little slower on your daily run, or becoming more easily fatigued in a basketball game with your kids. The gradual appearance of these signs of mental and physical decline is a normal part of aging. Unfortunately, mental decline is especially steep for those who develop Alzheimer’s disease. Alzheimer’s disease is the most common form of dementia, which is a general term for the state of impaired memory and loss of basic intellectual abilities that interferes with daily life . A great deal of research, particularly in recent years, has been dedicated to finding the best ways to stave off dementia and keep our minds and bodies in top condition as we age. So what have we learned?
Nature vs. Nurture: “Secrets” to staying healthy as you age
According to the New York Times, the number of centenarians – people 100 years of age or older – has increased threefold over the past twenty years, from 38,300 in 1990 to over 96,000 in 2009 . This likely reflects a number of different factors. Have you ever heard someone say, “ I hope I got those genes!” in reference to a particularly long-lived relative? This is because your genes have a significant impact on your natural lifespan – an effect estimated to be around 30% . In fact, centenarians were found to be 20 times more likely than the general public to have had a long-living relative . One recent study published this summer indentified genetic variants that were more common in centenarians than younger people . The scientists found 150 small genetic changes that were highly enriched in the centenarian population. Many of these differences were correlated with a lower risk of developing diseases associated with aging (such as dementia and hypertension), which suggests at least one explanation for why those individuals were longer-lived on average. However, these findings do not mean that having these genes will ensure that you will live to 100; rather, they give us some ideas about what genes contribute to longevity.
Although genetic factors affect longevity, your lifestyle choices may actually be more influential than your genes [2, 5]. A population-based study of centenarians living in the Boston area showed that one key to longevity is staying very active, both mentally and physically . Centenarians usually take daily walks or art lessons, spend time with their families, do not smoke, exercise more, and eat healthy. On the Japanese island of Okinawa, which has the highest proportion of centenarians in the world, a typical diet consists of whole grains, vegetables, and fish . Perhaps most interestingly, many centenarians are optimists, which suggests that positive thinking may help lead to longer life . Thus, some of the keys to longevity may include physical activity, a healthy diet, and maintaining an optimistic attitude.
Training your brain
Even among the elite group of centenarians, there is a subset suffering from mental illness. About 13% of all people over the ago of 65 have Alzheimer’s disease . Alzheimer’s patients often forget basic information, such as where they live and even their own children’s names. As keeping physically active is known to keep the body healthy, it has been suggested that similar exercises for the mind, such as playing brain teasers or doing crossword puzzles, could help keep the mind healthy. Although this idea has some scientific support, it did not undergo thorough scientific study before inspiring the emergence of a large industry that creates “brain training” games for both the young and the old.
Today, brain training games and devices – such as educational games for children, Sudoku, or crossword puzzles – are extremely popular. A Google search for “brain training” yields over five million results, with many sites making bold claims that playing their online word puzzles and memory games will help boost memory and improve the learning of new facts. But are these claims true? Several studies have indicated a positive (albeit modest) effect of brain training exercises on cognitive function, but a recent report, titled “Putting brain training to the test,” provides evidence to the contrary. This study systematically examined whether playing computerized brain games improved cognitive function in tasks other than the games themselves . One group that played computerized cognitive games (Group 1) was compared to another group that had received no specific cognitive training (Group 2). Over the course of the six-week study, Group 1 improved at playing the games on which they had been trained, yet performed no better than Group 2 when tested with a variety of new, related cognitive tests. The authors of the study concluded that playing computerized cognitive games did not translate to improvement on other cognitive tasks . This means that brain training games do not necessarily improve memory or the ability to complete complex tasks. Instead, it seems like brain training games mostly teach you to be better at playing the games themselves – which isn’t necessarily a bad thing, but runs counter to the claims of the companies creating these games.
Brain training and Alzheimer’s disease
Keeping the mind active can also help to stave off the debilitating effects of Alzheimer’s disease. Mentally active people who develop Alzheimer’s later in life often show physical signs of neurodegeneration prior to the manifestation of mental decline , meaning that they are able to function normally despite having areas of decay in the brain. A recent study examined this phenomenon more closely by asking whether Alzheimer’s disease had a similar rate of progression in people that were cognitively active versus those that were not . The study compared three groups of people: those without any cognitive delays, those with mild cognitive impairment, and those diagnosed with Alzheimer’s disease. It found that in those without any previous cognitive impairment, staying mentally active was associated with a delayed onset of dementia or Alzheimer’s. Those with mild cognitive impairment displayed no change with mental activity. Surprisingly, of those already diagnosed with Alzheimer’s, a high level of cognitive activity was associated with faster disease progression. That is, those who engaged in various brain training exercises delayed the onset of Alzheimer’s disease until much later in life; however, once they were diagnosed with Alzheimer’s, the disease progressed much faster. Scientists are not entirely sure why this is the case, but they believe that those people who stay mentally active are able to better cope with the physical deterioration of the brain as they age.
What can we take home from these studies? First, keeping your mind active with brain training games does not necessarily translate into better mental health as you age. Although staying mentally active correlates with longer life, these studies show that playing online cognitive games may not be the best way to maintain your cognitive health. Second, maintaining a healthy lifestyle through a balanced diet, exercise, and positive relationships can help to achieve longevity. The centenarians featured in the New York Times article exercise daily, eat healthy diets, stay in touch with their families, and have optimistic outlooks on life. There are, of course, some things out of one’s control that will affect longevity, such as genes and the surrounding environment. Scientists will continue to study these factors and how they contribute to longevity. Perhaps one day, we may unravel the complex interrelationships between these factors and long life.
Harvard Medical School
1. 2010 Alzheimer’s Disease Facts and Figures Report: http://www.alz.org/alzheimers_disease_facts_figures.asp
2. Brody, J. E. “100 Candles on Her Next Cake, and Three R’s to Get Her There.” New York Times, October 18, 2010. http://www.nytimes.com/2010/10/19/health/19brody.html?_r=1&scp=1&sq=centenarians&st=cse
3. Okinawa Centenarian Study: http://www.okicent.org/study.html
4. Sebastiani, P. et al. Genetic Signatures of Exceptional Longevity in Humans. Science, Published Online 1 July 2010. http://www.sciencemag.org/content/early/2010/11/10/science.1190532.abstract
5. Boston University School of Medicine New England Centenarian Study: http://www.bumc.bu.edu/centenarian/overview/
6. Owen, AM et al. (2010). Putting brain training to the test. Nature, 465: 775-778.
7. Wilson, R. S., et al (2010). Cognitive activity and the cognitive morbidity of Alzheimer disease. Journal of Neurology, 75: 990-996.
Links of interest
Interactive NY Times feature with stories of centenarians: http://www.nytimes.com/interactive/2010/10/19/health/20101018-centenarians-voices-photos.html
Cambridge Brain Sciences “provides scientifically proven tools for the assessment of cognitive function over the web.” http://www.cambridgebrainsciences.com/