Friday, July 03, 2009

SciAm - Fit Body, Fit Mind? Your Workout Makes You Smarter

http://www.scientificamerican.com/media/inline/does-exercise-really-make_1.jpg

Great article in support of exercise for a healthy mind, which I and others have been arguing for a long time.

Fit Body, Fit Mind? Your Workout Makes You Smarter

How can you stay sharp into old age? It is not just a matter of winning the genetic lottery. What you do can make a difference

By Christopher Hertzog, Arthur F. Kramer, Robert S. Wilson and Ulman Lindenberger

Key Concepts

  • We are used to thinking of intelligence as largely a matter of genetic inheritance, but that is not the whole picture. What you do affects your mental well-being: staying physically and mentally active helps us stay sharp as we age.
  • Nevertheless, our personal efforts to bolster cognitive enhancement cannot forestall all declines in our cognitive performance.
  • What is especially surprising is the powerful link between physical activity and mental acuity. Staying fit helps us keep cognition more robust as well.

As everybody knows, if you do not work out, your muscles get flaccid. What most people don’t realize, however, is that your brain also stays in better shape when you exercise. And not just challenging your noggin by, for example, learning a new language, doing difficult crosswords or taking on other intellectually stimulating tasks. As researchers are finding, physical exercise is critical to vigorous mental health, too.

Surprised? Although the idea of exercising cognitive machinery by performing mentally demanding activities—popularly termed the “use it or lose it” hypothesis—is better known, a review of dozens of studies shows that maintaining a mental edge requires more than that. Other things you do—including participating in activities that make you think, getting regular exercise, staying socially engaged and even having a positive attitude—have a meaningful influence on how effective your cognitive functioning will be in old age.

Further, the older brain is more plastic than is commonly known. At one time, the accepted stereotype was that “old dogs can’t learn new tricks.” Science has proved that this dictum must be discarded. Although older adults generally learn new pursuits more slowly than younger people do and cannot reach the peaks of expertise in a given field that they might have achieved if they had started in their youth, they nonetheless can improve their cognitive performance through effort—forestalling some of the declines in cognition that come with advancing age. As John Adams, one of the founding fathers and the second U.S. president, put it: “Old minds are like old horses; you must exercise them if you wish to keep them in working order.”

The news comes at a propitious time. The proportion of older adults in the U.S. and in other industrial nations continues to grow: in 1900, 4.1 percent of U.S. citizens were older than 65, but by 2000 that amount had jumped to 12.6 percent; by 2030, 20 percent of us will be in that category. From a societal point of view, prolonging independent functioning is both a desirable goal in itself and a way of deferring costs of long-term care. For individuals, maintaining optimal cognitive functioning is worthwhile simply because it promises to enhance quality of life through the years.

Mental Training
How to keep minds keen over an entire life span is a question philosophers have mulled since the earliest writings on record. As Roman orator Cicero put it: “It is exercise alone that supports the spirits, and keeps the mind in vigor.” Modern research in this field began in the 1970s and 1980s, with studies that demonstrated that healthy older adults can improve performance to a greater extent than had been previously assumed. The earlier research did not fully address certain questions, such as how long adults could retain the new skills they had acquired through training, whether those specifically developed skills would also positively influence other areas of cognition needed in everyday life, and whether the studies done with small numbers of subjects would be broadly applicable to most members of society.

The latest experiments confirm that cognitive training does show substantial benefits for older adults and that these effects can be relatively long-lasting. Around the turn of this past century the federal government’s National Institute on Aging funded a consortium of researchers to conduct a large-scale training study in a sample of older Americans. In 2002 psychologist Karlene Ball of the University of Alabama at Birmingham and her colleagues published initial results on more than 2,500 individuals older than 65 who had received about 10 sessions of cognitive training. Participants were randomly assigned either to a cognitive-process training group to learn how to excel in one of three areas—memory, reasoning or visual search—or to a control group of subjects who did not receive training. At a follow-up two years later, the team randomly selected a set of the initial participants to get booster training prior to evaluation. The results showed strong training-effect sizes in each group as compared with controls, along with a pattern of specificity in performance improvements. For example, individuals trained in visual search evinced strong gains in visual search performance but little improvement, relative to controls, on the memory and reasoning tests, a typical finding in training research. Data from retests five years later on the sample found that measurable training benefits were still present after the longer interval.

More impressive, however, are recent training studies that focus on what psychologists call executive function—how a person plans a strategic approach to a task, controls what is attended to, and how he or she manages the mind in the process. Unlike training that focuses on very specific skills, such as memorization strategies, training that aims to help people to control how they think appears to work on broader skills that are helpful in many situations that require thinking. For instance, psychologist Chandramallika Basak and her colleagues at the University of Illinois recently showed that training in a real-time strategy video game that demands planning and executive control not only improved game performance but enhanced performance on other tasks measuring aspects of executive control. Other results suggest that psychologists are learning how to train higher-level skills that may have a broader effect on cognitive function.

You don’t have to have specialized training, however, to achieve cognitive gains or ward off cognitive decline. Everyday activities such as reading can help. We reviewed evidence on activity-related cognitive enrichment in more than a dozen studies. In 2003 neuropsychologist Robert S. Wilson and his colleagues at Rush University Medical Center in Chicago recruited more than 4,000 elderly people from a geographically defined community and rated their frequency of participation in seven cognitive activities (for instance, reading magazines). At three-year intervals for a mean of nearly six years, participants completed an in-home interview that included brief tests of cognitive function. More frequent cognitive activity at the outset was associated with reduced rate of cognitive decline over time.

Getting Physical
Over the past decade several studies have underscored the link between physical activity and cognition. For instance, in a study published in 2001 neuropsychiatrist Kristine Yaffe of the University of California, San Francisco, and her colleagues recruited 5,925 women older than 65 at four different medical centers across the U.S. The participants were all free of any physical disability that would limit their ability to walk or pursue other physical activities. The volunteers were also screened to ensure that they did not have a cognitive impairment. The researchers then assessed their physical activity by asking the women how many city blocks they walked and how many flights of stairs they climbed daily and gave them a questionnaire to fill out about their levels of participation in 33 different physical activities. After six to eight years, the researchers assessed the women’s level of cognitive function. The most active women had a 30 percent lower risk of cognitive decline. Interestingly, walking distance was related to cognition, but walking speed was not. It seems that even moderate levels of physical activity can serve to limit declines in cognition in older adults.

Moderate movement is good, but toning your circulatory system with aerobic exercise may be the real key to brain fitness. In a 1995 study of 1,192 healthy 70- to 79-year-olds, cognitive neuroscientist Marilyn Albert of Johns Hopkins University and her colleagues measured cognition with a battery of tasks that took approximately 30 minutes to complete and included tests of language, verbal memory, nonverbal memory, conceptualization and visuospatial ability. They found that the best predictors of cognitive change over a two-year period included strenuous activity and peak pulmonary expiratory flow rate. In an investigation published in 2004 epidemiologist Jennifer Weuve of Harvard University and her colleagues also examined the relation between physical activity and cognitive change over a two-year period in 16,466 nurses older than 70. Participants logged how much time they spent per week in a variety of physical activities (running, jogging, walking, hiking, racket sports, swimming, bicycling, aerobic dance) over the past year and provided self-reports of walking pace in minutes per mile. Weuve’s group observed a significant relation between energy expended in physical activities and cognition, across a large set of cognitive measures.

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