Brain Rules (Updated and Expanded). John Medina

sitting around, seemingly waiting to die. One was named Jim. His eyes seemed vacant, lonely, friendless. He could cry at the drop of a hat but otherwise spent the last years of his life mostly staring off into space. I switched channels. I stumbled upon a very young-looking Mike Wallace. The journalist was interviewing architect Frank Lloyd Wright, in his late 80s. I was about to hear a most riveting conversation.

      “When I walk into St. Patrick’s Cathedral … here in New York City, I am enveloped in a feeling of reverence,” said Wallace, tapping his cigarette.

      The old man eyed Wallace. “Sure it isn’t an inferiority complex?”

      “Just because the building is big and I’m small, you mean?”

      “Yes.”

      “I think not.”

      “I hope not.”

      “You feel nothing when you go into St. Patrick’s?”

      “Regret,” Wright said without a moment’s pause, “because it isn’t the thing that really represents the spirit of independence and the sovereignty of the individual which I feel should be represented in our edifices devoted to culture.”

      I was dumbfounded by the dexterity of Wright’s response. In the space of a few moments, one could detect the clarity of his mind, his unshakable vision, his willingness to think outside the box. The rest of the interview was just as compelling, as was the rest of Wright’s life. He completed the designs for the Guggenheim Museum, his last work, in 1957, when he was 90 years old. But I also was dumbfounded by something else. As I contemplated Wright’s answers, I remembered Jim from the nursing home. He was the same age as Wright. In fact, most of the residents were. I was beholding two types of aging. Jim and Frank lived in roughly the same period of time. But one mind had almost completely withered, seemingly battered and broken by the aging process, while the other mind remained as incandescent as a light bulb.

      What was the difference in the aging process between men like Jim and the famous architect? This question has intrigued the research community for a long time. Attempts to explain these differences led to many important discoveries. I have grouped them as answers to six questions.

       1) Is there one factor that predicts how well you will age?

      When research on aging began, this question was a tough one to answer. Researchers found many variables, stemming from both nature and nurture, that contributed to someone’s ability to age gracefully. That’s why the scientific community was both intrigued and cautious when a group of researchers uncovered a powerful environmental influence. One of the greatest predictors of successful aging, they found, is the presence or absence of a sedentary lifestyle.

      Put simply, if you are a couch potato, you are more likely to age like Jim, if you make it to your 80s at all. If you have an active lifestyle, you are more likely to age like Frank Lloyd Wright—and much more likely to make it to your 90s. The chief reason for the longer life is that exercise improves cardiovascular fitness, which in turn reduces the risk for diseases such as heart attacks and stroke. But researchers wondered why the people who were aging well also seemed to be more mentally alert. This led to an obvious second question.

       2) Were they more mentally alert?

      Just about every mental test possible was tried. No matter how it was measured, the answer was consistently yes: A lifetime of exercise results in a sometimes astonishing elevation in cognitive performance, compared with those who are sedentary. Exercisers outperform couch potatoes in tests that measure long-term memory, reasoning, attention, and problem-solving skill. The same is true of fluid-intelligence tasks, which test the ability to reason quickly, think abstractly, and improvise off previously learned material in order to solve a new problem. Essentially, exercise improves a whole host of abilities prized in the classroom and at work.

      What about people who aren’t elderly? Here, the number of studies done thins out. But in one case, researchers looked at more than 10,000 British civil servants between the ages of 35 and 55, grading their activity levels as low, medium, or high. Those with low levels of physical activity were more likely to have poor cognitive performance. Fluid intelligence, the type that requires improvisatory problem-solving skills, was particularly hurt by a sedentary lifestyle.

      Not every cognitive ability is improved by exercise, however. Short-term memory, for example, and certain types of reaction times appear to be unrelated to physical activity. And, while nearly everybody shows some improvement, the degree varies quite a bit among individuals. It’s one thing to look at a group of people and note, as early studies did, that those who exercise are also smarter. It’s another thing to prove that exercise is the direct cause of the benefits. A more intrusive set of experiments needed to be done to answer the next question.

       3) Can you turn Jim into Frank?

      Like producers of a makeover show, researchers found a group of elderly couch potatoes, measured their brain power, exercised them, and then reexamined their brain power. The researchers consistently found that all kinds of mental abilities began to come back online—after as little as four months of aerobic exercise. A different study looked at school-age children. Children jogged for 30 minutes two or three times a week. After 12 weeks, their cognitive performance had improved significantly compared with prejogging levels. When the exercise program was withdrawn, the scores plummeted back to their preexperiment levels. Scientists had found a direct link. Within limits, it does appear that exercise can turn Jim into Frank, or at least turn Jim into a sharper version of himself.

      As the effects of exercise on cognition became increasingly clear, scientists asked the question dearest to the couch-potato cohort:

       4) What type of exercise must you do, and how much?

      After years of investigating aging populations, researchers’ answer to the question of how much is not much. If all you do is walk several times a week, your brain will benefit. Even couch potatoes who fidget show increased benefit over those who do not fidget. The body seems to be clamoring to get back to its active Serengeti roots. Any nod toward this evolutionary history, be it ever so small, is met with a cognitive war whoop. In the laboratory, the gold standard appears to be aerobic exercise, 30 minutes at a clip, two or three times a week. Add a strengthening regimen and you get even more cognitive benefit. Individual results vary, of course, and exercising too intensely, to exhaustion, can hurt cognition. One should consult a physician before embarking on an exercise program. The data merely point to the fact that one should embark. Exercise, as millions of years traipsing around the globe tell us, is good for the brain. Just how good took everyone by surprise, as they delved into the next question.

       5) Can exercise treat dementia or depression?

      Given the robust effect of exercise on typical cognitive performance, researchers wanted to know if it would have an effect on atypical performance. What about diseases such as age-related dementia and its more thoroughly investigated cousin, Alzheimer’s disease? What about affective (mood) disorders such as depression? Researchers looked at both prevention and intervention. With experiments reproduced all over the world, enrolling thousands of people, often studied for decades, the results are clear. Your lifetime risk for general dementia is literally cut in half if you participate in physical activity. Aerobic exercise seems to be the key. With Alzheimer’s, the effect is even greater: Such exercise reduces your odds of getting the disease by more than 60 percent.

      How much exercise? Once again, a little goes a long way. The researchers showed you have to participate in some form of exercise just twice a week to get the benefit. Bump it up to a 20-minute walk each day, and you can cut your risk of having a stroke—one of the leading causes of mental disability in the elderly—by 57 percent.

      Dr. Steven Blair, the man most responsible for stimulating this line of inquiry, did not start his career wanting to be a scientist. He wanted to be an athletics coach. Surely he was inspired by his own football coach in high school, Gene Bissell. Bissell once forfeited a winning game. He realized after the game that an official had missed a call, and he insisted that his team be penalized. Young Steven never forgot the incident.