To all who went there before us, and showed us the way to age well

ACKNOWLEDGMENTS

A bit more than four years ago, I received an e-mail from Alan Rinzler, an eminent editor I knew by reputation but had never met, asking if I’d be interested in writing a book in collaboration with Scientific American about a day in the life of your brain. That was the beginning of what would turn out to be a challenging series of four brain books in four years. He edited three and set the tone for this one before retiring from Jossey-Bass last year. Thank you, Alan. And here’s to all of those at Jossey-Bass and John Wiley & Sons who made these books possible, most of whom have worked with me on all four books: Paul Foster, who started it all with an idea about a day in the life of your brain; my editors, Nana Twumasi and Marjorie McAneny, who proffered calming support as well as edits; Carol Hartland, the production genius who pulled it all together; Bev Miller, an extraordinarily insightful copyeditor; Paula Goldstein, the terrific book designer; and the marketing crew who put my books in your hands, including Jennifer Wenzel, Samantha Rubenstein, and Jeff Puda.

Kelly A. Dakin has been of inestimable help with research and fact checks through all four books as she earned her Harvard doctorate in neurobiology. Brianna Smith, an amazing research assistant, trolled years of Scientific American articles—speaking of which, thanks to Karin Tucker and Diane McGarvey of Scientific American for their patience in finding and approving the use of hundreds of articles. And many thanks to literary agent Andrea Hurst, the godmother of the brain books who first suggested my name to Alan.

Many distinguished scientists have given me their time, expertise, and support, for which I am so very grateful. Two in particular have helped with all four of these books, reading, correcting my errors, and suggesting edits: John Dowling of Harvard College, the Llura and Gordon Gund Professor of Neuroscience, who also generously provided the basic information on brain development in this book; and R. Douglas Fields, chief of the Nervous System Development and Plasticity Section, National Institutes of Health, and editor in chief of the journal Neuron Glia Biology, who is as extraordinary a writer as he is a scientist. All errors are mine.

Every writer needs first readers—those who ask, “Say what?” or gently point out a mistake, and again I have been blessed. Ann Crew has previewed all of my books; thanks this time also to JT Long, Robin MacDonald, Ferris Urbanowski, Frank Urbanowski, Judith Auberjonois, and Joan Aragone. The very generous Sacramento Writers Who Wine have buoyed me over many rough spots.

And thanks most especially to my brilliant daughters who observed how very hard I had to work to understand neuroscience and who concluded with satisfaction that the process just might have prompted enough new neurons to see me through old age. Alcina and Ariadne, you are truly my best work.

PREFACE: LIVE LONG, AND LIVE WELL

Most of us would agree we are happier being older. As they say, it’s better than the alternative. If only we didn’t have to endure all the physical issues that go along with aging.

The aversion to aging has created a multibillion-dollar-a-year anti-aging industry (estimated to be $291 billion by 2015), supported by those who believe they can turn back the clock on body and mind. Alas, it’s just not so. We age at different rates, and some of us may look, feel, and act younger than our age—and, yes, some healthy choices may actually keep us younger in mind and body.

But there is no such thing as anti-aging, and aging is not a disease: it’s what happens if you are lucky enough to live long enough.

So here’s a spoiler alert about this book. It is not about anti-aging. It’s about how and why your brain grows older; the normal changes to expect in a healthy aging brain; some conditions and diseases that may challenge you and your brain, including Alzheimer’s disease and other dementias; and what neuroscience is showing you can do to optimize healthy aging.

For if you can’t thwart aging, there is plenty you can do to age well. Research shows, for openers, that your brain most likely will not deteriorate rapidly with age but rather will recede more subtly. Alzheimer’s disease is terrible and affects millions, but it is not inevitable. Indeed, some healthful and commonsense practices are connected with lower risks of dementia.

For most of us, older is indeed happier, and researchers are finding that happiness may be its own reward: living an active, optimistic life with many friends and lots of leisure-time activities increases not only the quality of your life but the longevity of you and your brain.

Sources

“Global Anti-Aging Products Market to Reach $291.9 Billion by 2015, According to New Report by Global Industry Analysts,” WorldHealth.net, Feb. 18, 2009, http://www.worldhealth.net/news/global_anti-aging_products_market_to_rea/.

INTRODUCTION
Welcome to the New Old Age

In all of history, there has never been a better time to grow old.

First, we can grow old. At the start of the twentieth century, the average life span was 47. Today the global average is 68, and for those born today in Western developed countries, it’s around 80, nearly double in little more than a century.

The longer you live, the longer you may live. Consider this: for a 65-year-old woman today, the average—average!—life span is 84.8, or 19.8 more years. And at age 75, that jumps to 87.6 years. A man who is 75 years old today can expect to live to 85.5. If you’re taking care of yourself, there could easily be more years.

Second, thanks to modern medicine and technologies, we don’t look or act as old as our ancestors did. Those of us past the midcentury mark who can recall our grandparents know that with the outstanding exception, they were not usually participating in an active lifestyle. If they were still alive by their 70s, often they were sedentary, ill, or failing.

True, the absolute life span has not increased, with 122 being the oldest age recorded. But more of us are living longer than at any time in the past, and living better.

What’s Old, Anyway?

Today in developed countries, it seems to be accepted that young old age begins in the late 60s and that old old age comes after the age of 80.

The answer depends, of course, on who you ask. There’s a remarkable generation gap when it comes to determining when old age begins according to a 2009 national survey, Growing Old in America, by the Pew Research Center. Among the nearly three thousand surveyed, those between ages 18 and 29 said they believed that the average person becomes old at age 60, middle-aged respondents put it closer to 70, and those ages 65 and above say that old begins at age 74. The researchers’ conclusion after massaging the data: old age begins at 68.

But that doesn’t mean you’re old at 68—at least in your own mind. Other questions revealed that while young people in the survey felt their chronological age or older, oldsters don’t: only 21 percent between ages 65 and 74 and 35 percent over age 75 said they feel old. In fact, a third of those aged 65 to 74 said they feel ten to nineteen years younger than their age, and one in six said they feel at least twenty years younger than their actual age.

There’s evidence to back that up. Today’s 60 and 70 year olds are to a large extent out in the workforce: 16 percent of us are still on the job (and 55 percent of those full time) because we want to be or perhaps because economics demand it. At the age that our grandparents were getting dentures and new rocking chairs (if they didn’t already), we’re getting braces on our teeth and investing in gym memberships, starting new businesses, trekking in Nepal, running silver marathons—and having sex: even those in their 80s report they are sexually active. And the bar has been rising. Increasingly “old old age” refers to those who have reached one hundred and up. Centenarians, in fact, are the fastest-growing demographic group in the world.

Our bodies do need more maintenance, but the specter we face and most fear is not the onslaught of bodily infirmities or even an untimely death. For most of us, it’s the fear we will outlive our brain’s useful life. What good are twenty extra years if our brains and minds are not able to enjoy them? If we become a burden on those we love or live out those years in institutional care?

Fortunately there’s some good news about the continued health of the mature and aging brain and about how to increase your potential for an active and alert elder mind. It’s going to take some work and perhaps self-discipline, two items some retirees tend to think they shed along with their jobs.

Research is showing that dementia, depression, and delusions are not normal parts of aging. Rather, they are diseases that in some cases can be averted or treated. Yes, your aging brain will slow and lose some of its edge, but it will still be able to serve you quite well. The elder brain remains plastic—able to learn new things and create new networks and memories. And the older brain is the happier brain: less prone to react in anger, more likely to recall pleasant memories than the negative past.

Indeed, there’s much to enjoy in those final decades, especially if you put some effort into a healthy lifestyle, diet, and attitude.

How Scientists Are Researching Your Brain

Every day scientists are finding out more about your aging brain. This book is chock full of information from some of those research studies. To get all of this information, scientists use several research tools:

• They ask you: Interviews. Surveys and questionnaires tell us what people say they think and feel. Since the information is self-reported, it may not be completely objective. For example, recent studies where some elderly men said they have intercourse every week may not be true—but it shows these men are still thinking about sex in old age.

• They watch you: Observation. Watching animals and people as they react to situations, stimuli, or cognitive tests hints at what is going on in the brain and helps to connect the actions with the amount and location of brain activity.

• They sample your tissue and fluids: Laboratory tests. Humans and other mammals produce specific neurochemicals and hormones related to actions and emotions. Measuring these chemicals gives insights into what people are thinking and feeling, as well as what their brains are doing. For example, scientists have found that high levels of stress release chemicals that can age your brain.

• They wire you up: Electroencephalography. An older technique, it is still useful to record your brain’s electrical activity from outside your skull.

• They look inside your brain: Brain scans. A host of imaging techniques and tools shows which parts of your brain are active when you are feeling or performing an activity and can show brain damage. But they have limits.

Sources

Life expectancy statistics: Centers for Disease Control, Health, United States, 2010, http://www.cdc.gov/nchs/hus.htm.

What’s old, anyway? Pew Research Center Social and Demographic Trends survey, “Growing Old in America: Expectations vs. Reality,” 2009, http://pewresearch.org/pubs/1269/aging-survey-expectations-versus-reality. U.S. Census Bureau, “Facts for Features,” 2010 Census, http://www.census.gov/newsroom/releases/archives/facts_for_features_special_editio ns/cb11-ff08.html.

How scientists are researching your brain: Adapted from Judith Horstman, The Scientific American Brave New Brain (San Francisco: Jossey-Bass, 2010).

Tools for looking inside your brain: Adapted from Horstman, The Scientific American Brave New Brain.

PART ONE
How Your Brain Grows

CHAPTER ONE

The Well-Aged Brain

Older and Happier

Growing older is a limiting of possibilities. At age 20, that’s a depressing prospect. By age 60 or so, it’s a relief. By 70 and beyond, it may be one of the reasons older folks are happier.

Yes, that’s right: emotional well-being actually improves with age, according to studies from many different countries and cultures. Starting sometime after 60, folks tend to be happier, worry less, and have less stress. Wide-scale studies confirm it (and no, it’s not a result of the forgetfulness of dementia).

Furthermore, research on creative accomplishments indicates that in some disciplines, such as the arts, history, and fiction writing, many people produce their best work in their 50s or even decades later. Philosophy, leadership, and politics are other areas in which the older person flourishes—hence, the term elder statesman.

The Myth of a Sad Old Age

Think of someone who is depressed, cantankerous, lonely, sexually inactive, and forgetful. Did an elderly person come to mind?

The answer, it turns out, depends on your age. Not surprisingly, a research team that surveyed adults at various ages found young adults (between ages 21 and 40) predicted that people would become less happy as they got older. In one survey, 65 percent of psychology students agreed that “most older people are lonely and isolated,” and in another survey, 64 percent of medical students agreed that “major depression is more prevalent among the elderly than among younger persons.”

Shows how much these whippersnappers know. The truth is actually just about the opposite. Population-based surveys reveal that rates of depression are highest in those between the ages of 25 and 45, and about half as high for independently living elders.

And they are happier too. In recent studies, adults older than age 60 were actually happier than the younger respondents, and happiness continued to increase with aging. The happiest group overall is men aged 65 and older.

Where does this negative image of aging come from? Look no further than the entertainment available for your children (or grandchildren). Dubious depictions of the aged begin early in life. In Disney children’s films, researchers found that 42 percent of elderly characters are portrayed in a less-than-positive light and as forgetful or crotchety. Unflattering renderings also pervade films aimed at adolescents. In a study of popular teen movies, most elderly characters were shown with negative characteristics, and a fifth fulfilled only off-putting stereotypes.

What’s worse, studies show that some elderly people share these stereotypes. Talk about fiction! It might be time for a positive-aging action group.

Actually, It’s Getting Better All the Time

Despite the very real and weighty concerns associated with aging, such as planning for retirement, health issues, and the death of companions and loved ones, it seems that many people in the United States actually get happier with age—and this is regardless of whether they are employed or retired, have young children at home, or live alone or with a partner. The fact is that growing older is, for many of us, growing happier.

Several studies show that happiness increases through the late 60s and into the 70s and perhaps beyond. In one study of twenty-eight thousand Americans, a third of the 88 year olds reported being “very happy,” and the happiest individuals surveyed were the oldest. Indeed, the odds of being happy increased 5 percent with every decade.

Interestingly, research by Stanford University psychologist Laura Carstensen and colleagues collected over ten years found that compared with younger people, older people are more likely to recall positive than negative information, perhaps accounting partly for their often surprisingly rosy outlook on life. Older people are not generally lacking in sexual desire either. (See “Do You Think I’m Sexy?” later in this chapter.) The researchers also found that emotional experience predicted mortality: controlling for age, sex, and ethnicity, those who said they had more positive than negative emotions in everyday life not only had an improved quality of life but were more likely to have survived over a thirteen-year period.

The observation of preserved well-being flies so much in the face of stereotypes about aging that it is often met with disbelief in both the general population and the research community, Carstensen and colleagues reported. And some older people themselves share pessimistic views about the “typical” older person.

Another wide-ranging study found that in older years, the emotional flames that threatened us with self-destruction have become comforting embers in most cases. Passions run deep, but not as hot and certainly not as out of control. They reported that

• Happiness peaked around age 20—and then again in those who were in their early 70s, when their feeling of well-being was up to late-teen levels.
• The middle years may be the hardest. General well-being fell sharply through the age of 25, stress peaked between the ages of 22 and 25, worry persisted for those between their 20s and 40s—and both decreased drastically after the mid-50s.
• Anger and stress steeply declined after the early 20s.
• Sadness increased through the 40s, falling off in the mid- to late 50s.
• Oldsters recalled fewer negative memories than younger adults did, and positive emotions outweighed negative ones

The data came from a 2008 phone survey of 340,847 randomly selected adults aged 18 to 85 performed by the Gallup Organization. The researchers in the study noted that the findings fit in with proposals that “older people are more effective at regulating their emotions than younger adults” and that older adults tend to “recall fewer negative memories than younger adults” do.

These findings come from a fairly average slice of the middle-class U.S. population and are similar to studies from more than seventy countries that show a U-shaped pattern of youthful happiness followed by midlife worry and stress and then later-life happiness.

In this study, about 29 percent of those queried had a college degree and a median monthly average household income between $3,000 and $3,999. During the call, participants were asked to rate how they currently felt their life stood on a scale of 0 (“the worst possible life for you”) to 10 (“the best possible life for you”). They were then asked if they had felt differently (happiness, enjoyment, stress, sadness, anger, and worry) “a lot of the day yesterday.”

“As people age, they are less troubled by stress and anger,” researchers noted in their study, which was led by Arthur Stone of the Department of Psychiatry and Behavioral Science at Stony Brook University. “And although worry persists, without increasing, until middle age,” they continued, “it too fades after the age of 50.”

This is not true for everyone, of course. Many do feel less happy with aging, including some people facing challenges with health or mobility issues, financial problems, or feelings of loneliness or loss. But quite a few of us are not just getting older; in terms of well-being, we’re getting better.

Great Late Achievers

Many well-known people have produced some of their best work after their 60s, some made major accomplishments well into old old age, and some of our iconic rock and roll figures are still, well, rocking and rolling. At 69, Mick Jagger and Keith Richards (born in 1943) are still Rolling Stones; at 71, Bob Dylan remains Forever Young (1941); at 73, Tina Turner (1939) is still turning heads; and at age 86, Tony Bennett (1926) is performing and painting.

And it’s not just performers: scientists have among the best of aging brains. Two of the most eminent scientists of the twentieth century, Albert Einstein (1879–1955) and Thomas Alva Edison (1847–1931), worked up to the time of their deaths at ages 76 and 84, respectively. Nobel laureate Eric Kandel (1929) and neuroscientist Brenda Milner (1918), who received a major award at age 92, are among many elder scientists who have not retired.

Are Grandparents Safer Drivers?

Those added years may also add up to safety. Grandchildren seem to be 50 percent safer in crashes when driven by grandparents than by their parents, a study in Pediatrics finds.

Researchers looked at a cross-sectional study of motor vehicle crashes from January 15, 2003, to November 30, 2007, involving children aged 15 years or younger. The cases were culled from insurance claims with data collected by follow-up telephone surveys. They found that children driven by grandparents made up 9.5 percent of the sample but resulted in only 6.6 percent of the total injuries, even though the study also revealed the grandparents did not always use the best available child-restraint systems in the car. Researchers speculated there was an unaccounted-for protective grandparent driving style and wondered if grandparents, made nervous about the task of driving with the precious cargo of their grandchildren, establish more cautious driving habits. Of note is that these were younger grandparents for the most part, with the median age 58, although the age range went from 43 to 77.

Do You Think I’m Sexy? Apparently, Yes—at Any Age

Health willing, age does not wither sexual desire. Recent studies and surveys show the brains of those well over 60 years old want and enjoy sex.

In a national survey, more than three-quarters of men aged 75 to 85.5 and half of their female counterparts reported interest in sex and said they were sexually active. Among 75 to 85 year olds, 26 percent said they were sexually active.

Other studies find that age plays a role in marital happiness. A longitudinal study by sociologist Debra Umberson of the University of Texas at Austin and her colleagues measured the independent effect of age—as opposed to duration of marriage—and discovered that the older the spouses, the more likely they are to have a good marriage. They suggest it’s perhaps because older couples are calmer and less emotionally reactive in marital conflicts than younger people or because they better appreciate their partner’s positive traits.

Studies also suggest that in old age, men seem to want sex more than women do—and they get more, or at least they say they do (that doesn’t seem much different than for younger men).

That could be partially explained by the dearth of men to partner aging women, who survive them. The American Association for Retired Persons (AARP) commissioned the Sex, Romance, and Relationships: 2009 AARP Survey of Midlife and Older Adults, the third it has prepared in the past decade.

The report queried about 1,670 people 45 years and older about sexual attitudes and practices and found that even in old age, men continue to think about sex more often than women do, see it as more important to their quality of life, engage in sexual activities more often, are less satisfied if they don’t have a partner, and are twice as likely as women (21 percent versus 11 percent) to admit to sexual activity outside their relationship.

And, the report continues, both the frequency and satisfaction of sexual encounters were higher among those unmarried and dating (or engaged) individuals than among the married. Forty-eight percent of those who are single and dating said they have intercourse at least once a week, compared to 36 percent of those who are married. In addition, 60 percent of dating singles are satisfied with their sex lives compared to 52 percent of those who are married.

Overall, however, there has been a dip in reported satisfaction with sexual activity: in 2004, 51 percent told AARP they were satisfied with their sex lives, and in 2009 it was 43 percent. One possible factor for the cooling ardor among elders: the economic chill and concerns. The percentage who said better finances would make their sex lives more satisfying increased from 2004 to 2009 (from 17 to 26 percent among men and 9 to 14 percent among women).

Age can affect some sexual activities in men, who may have erectile dysfunction and find it more difficult to get or keep an erection, but older women don’t usually have as many problems with sexual function. Of course, good health is equated with good sex, and in the AARP survey, health was among the top concerns voiced about sexual satisfaction. Women outliving their male partners and potential partners may account for their getting less sexual activity in later years, but men lose more years of sexual activity due to health issues than do women. Frailty or mobility problems can also take the bloom off sexual performance.

Sex among the aging was confirmed by another study of sex life in the United States that looked at reports from more than eight thousand people in three databases. It found that among those aged 65 to 74, 67 percent of men and 40 percent of women said they had been sexually active in the past year. Even among the oldest in the report, those 75 to 85 years old, 38.9 percent of men and 16.8 percent of women were sexually active.

And apparently still acting like crazy, irresponsible kids. One of the really startling findings shows that older is apparently not wiser: homosexual or heterosexual, the AARP study found that only one in five sexually active older singles reported using a condom regularly, and only 12 percent of the men and 32 percent of women said they used one every time. Not surprisingly, grandparents and even great grandparents had sexually transmitted diseases, from vaginitis to syphilis, gonorrhea, and genital warts, and 1 percent had HIV/AIDS. Data from the Centers of Disease Control and Prevention show that sexually transmitted diseases have skyrocketed among those 55 and older in the past few years.

One caveat: Remember that all of these studies about sexual activity depended on self-reporting—what the participants said about their sexual activity—and a slightly cynical person might be a wee bit suspicious at the level of activity the elderly men reported. So we might want to take the claims of men about their later life sexual activity with a grain of salt. Even so, if nothing else, these study results sure show older guys are thinking about sex quite a bit.

A Swell of Centenarians: One Hundred Reasons to Take Care of Your Brain

Jeanne Calment of France was 122 when she died in 1997, making her the longest-lived person known to date. Reaching the age of 100 years or more used to be rare. But today centenarians are the fastest-growing age group in the United States, with more than seventy-two thousand as of 2010. Experts predict there may be as many as 1 million by 2050.

If you’re 60 years old (or younger) today, you could be in that group. You’ll have plenty of company near your age: people aged 80 and older are the fastest-growing portion of the total population in many countries. By 2040, the number of people 65 or older worldwide will hit 1.3 billion, according to the National Institute on Aging. For the first time in human history, there will be more people in the world aged 65 and older than there will be children under the age of 5, with the most rapid increase in developing countries.

If you do live to 100, you’ll want your mind intact, and if you are fortunate enough to possess a certain gene, it ups the odds of aging smartly. Nir Barzilai of the Albert Einstein College of Medicine and his colleagues examined 158 elderly people of Ashkenazi Jewish descent. Centenarians who passed a thirty-question test were two to three times as likely to have a common variant of the so-called CETP gene as those who did not, and those between ages 75 and 85 were five times as likely. The CETP gene variant leads to larger-than-normal cholesterol particles in the blood, the size perhaps making them less likely to lodge in the lining of blood vessels and thus lowering the risk of heart attack and stroke, which damage the brain.

But genes are not destiny, as studies of identical twins show. Your lifestyle practices play a major part in the health of your brain. A goodly part of this book examines normal aging, the threats to your brain health, and what you can do that could lower your risks of dementia and other brain-based conditions and perhaps join that premier One Hundred Club.

Sources

The myth of a sad old age and the major myths of aging: Scott O. Lilienfeld, Steven Jay Lynn, John Ruscio, and Barry L. Beyerstein, “Busting Big Myths,” Scientific American Mind, Mar.–Apr. 2010. Pew Research Center Social and Demographic Trends Survey, “Growing Old in America: Expectations vs. Reality,” 2009, http://pewresearch.org/pubs/1269/aging-survey-expectations-versus-reality. Marion Sonnenmoser, “Experience Versus Speed,” Scientific American Mind, June 2005. Retirement data from Christina Bamia, Antonia Trichopoulou, and Dimitrios Trichopoulos, “Age at Retirement and Mortality in a General Population Sample: The Greek EPIC Study,” American Journal of Epidemiology, 2008, 167(5), 561–569.

Actually, it’s getting better all the time: Scott O. Lilienfeld, Steven Jay Lynn, John Ruscio, and Barry L. Beyerstein, “Older and Sadder,” from “Busting Big Myths in Popular Psychology,” Scientific American Mind, Mar.–Apr. 2010. Katherine Harmon, “It’s Getting Better All the Time,” May 17, 2010, scientificamerican.com, http://www.scientificamerican.com/blog/post.cfm?id=its-getting-better-all-the-time-hap-2010-05-17. Laura Carstensen and others, “Emotional Experience Improves with Age: Evidence Based on Over Ten Years of Experience Sampling,” Psychology and Aging, 2011, 26, 21–33, doi:10.1037/a0021285. Arthur A. Stone and others, “A Snapshot of the Age Distribution of Psychological Well-Being in the United States,” Proceedings of the National Academy of Sciences, June 1, 2010, pp. 9985–9990.

Great late achievers: Hampton Roy and Charles Russell, “The Encyclopedia of Aging and the Elderly,” . R. Coniff, “Living Longer,” in E. Goldstein (ed.), (Boca Raton, Fla.: Social Issues Resource Series, 1981).