Bob Green's book 20 Years Younger
Chapter 1: The Science of Aging
The longer I live, the more beautiful life becomes.

—Frank Lloyd Wright

Everyone has a notion of what it means to age. Whether it's a snapshot in your head of how your parents have slowed down or lines you see on your own face, for many people it has something to do with decline. Things not being the way they used to be. Everything less than before. A lot of people feel that aging is about loss. And in some ways it is. "Aging is a wide range of physiological changes that make us more susceptible to death, limit our normal functions and render us more susceptible to disease," says João Pedro de Magalhães, PhD, a researcher on the biology and genetics of aging and a lecturer at the University of Liverpool in England. I would add that the physiological changes that take place as we age can also render us more susceptible to psychological downturns. It's not uncommon for people to lose enthusiasm as they get older, disheartened by their physical deterioration and inability to live the way they used to.

Do we have to age? It's the $6 million—or maybe I should say $6 billion—question and it's one that researchers the world over are donating a lot of time and money to answering. Some scientists are even hoping to answer the inevitable next question: Do we have to die? I don't think we're all that much closer to immortality than Ponce de León was when he went searching for the fountain of youth in 1513. However, we do have a much greater understanding of the aging process. And we are living longer: Over the last 150 years, the average life span has climbed from about age 45 to closer to age 80.

Living longer is important, but the ultimate goal is to live longer and live well into your later years. And through the science of aging we now know that it's very possible. In fact, it's become clearer that not all the effects of aging we've come to expect are inevitable, and that by making certain lifestyle choices you can dramatically slow those effects down—and maybe, in some cases, even eradicate them. We all age—that is undeniable—but your likelihood of aging poorly increases if you decide to sit back and leave well enough alone. To the contrary, take action and you'll retain your vitality, age gracefully and, yes, have a longer, better life.

Each of the subsequent chapters in this book asks you to make certain lifestyle changes toward that goal. The reasons behind those changes will be clearer if you know a little bit about the theories of why we age and the physiological consequences of growing older.

Theories on Why We Age
Scientists have long debated a central question about aging: Why? Why do we age? Many of them, both past and present, fall into the evolutionary camp. In the late 1800s, a German by the name of August Weismann was one of the first to promote an evolutionary theory. He believed that we're programmed to age and die in order to make room for the younger generation, continuing the evolution and betterment of the species. You might call it planned obsolescence.

Over time, the evolutionary theory of aging has, well, evolved and other theories have risen to the fore. One, called the mutation accumulation theory, is based on the idea that undesirable genes that cause the death of children get weeded out; they're not passed on to the next generation. But undesirable genes that don't cause death until late in life get passed on from generation to generation because the people who have those genes have children before their death. Over successive generations, those genes have accumulated, predisposing people to contract diseases as they grow old, then die.

Another well-known evolutionary theory is called the antagonistic pleiotropy theory. Its central idea is that some genes may be beneficial to us in our early lives but detrimental to us as we grow older. For instance, genes that increase a woman's ability to reproduce may also ultimately lead to menopause and all the health hazards (among them, bone loss and an increased risk of heart disease) that go with it. According to the antagonistic pleiotropy theory, evolution may select for genes that favor youth because the chances that humans and other organisms will survive accidents, predators and disease to live long lives are slim (or at least they were before modern medicine).

The other major theories on why we age have less to do with evolution and more to do with the cumulative effects of damage to the body. Over the years, injury from simple wear and tear, sun damage, a poor diet, smoking, pollution, even the body's own metabolic processes, add up to promote aging and eventual death. One of the most prominent of these theories focuses on oxidative stress. Oxidative stress refers to the injury done to DNA, cells and tissues in the body by free radicals, molecules with unpaired electrons that are produced when the body metabolizes oxygen. Free radicals also become present in the body through all the injurious means I just mentioned (poor diet, etc.). In their incomplete state, free radicals become thieves, stealing electrons from other molecules and wreaking havoc along the way. The damage they leave in their wake is often compared to the rusting of metal. The body has the ability to absorb free radicals and repair the damage they do, but its defense system tends to weaken over time, leaving it vulnerable to disease.

Like all theories about the cause of aging, the oxidative stress theory is just that, theory. We don't know for sure if unbound free radicals are the main cause of aging; however, we do know that free radicals cause harm and that oxidative damage can certainly age your body, decrease your quality of life and even shorten your life span. More specifically, by damaging a cell's DNA, oxidative stress can be the first step to transforming a healthy cell into a cancer cell (cancer also has other causes, such as inherited genetic mutations).

Free radicals influence LDL (bad) cholesterol as well, making it even more prone to sticking to the walls of arteries and increasing the risk of heart disease, stroke, erectile dysfunction and other conditions. Many of the strategies you'll read about in this book are aimed at preventing and repairing free radical damage. I'll be recommending many foods that contain antioxidants such as vitamin E, vitamin C and certain phytonutrients that disarm and disable free radicals. These dietary watchdogs also boost the body's own free radical defense system.

Likewise, the exercise program will help turn up your body's own free radical-fighting capabilities. A lot of Dr. Lancer's skincare recommendations also focus on quenching free radicals that degrade collagen and elastin, the proteins that give skin its structure and bounce. In addition to free radicals, inflammation has been implicated in aging because of the role it plays in so many age-related diseases. (They're actually related—free radicals can cause inflammation.) Short-lived inflammation is a good thing; it's the body's defense against a flu virus, bacteria, a wound, a chemical irritant and other kinds of trauma. Inflammation occurs when, triggered by damage, immune cells rush into the injured area, releasing compounds that destroy bacteria or promote wound healing. When the condition resolves, the immune response goes away. At least, most of the time. Sometimes, for a number of reasons, inflammation persists. That's called chronic inflammation, and it's been linked to everything from cancer and heart disease to diabetes, dementia and even wrinkles. While it's far from certain that inflammation is the major culprit in aging, anything you can do to reduce inflammation—such as exercise regularly—will reduce the cumulative effects of aging.

In the evolutionary theory of aging, genes determine aging and, ultimately, death. In the damage theory of aging, factors such as unhealthy food, stress and even the body's own metabolic processes are the primary agents. However, many people, including me, believe that aging is a combination of both. All the recommendations in this book, in fact, are predicated on the idea that you are working both with your own genetic predispositions and with the things in life that you can control, such as what you eat and how much you exercise.
The Aging Brain
Using MRI and other imaging technologies, researchers have learned that your brain starts to get smaller as you get older. "The volume of the frontal cortex, which is responsible for reasoning, problem-solving and strategic tasks, gets smaller, and white matter gets more porous; it's not as tightly woven as it was," explains Denise Park, PhD, director of the Center for Vital Longevity in Dallas.

These changes may explain why most people experience subtle declines in the rate at which they process new information, the amount of information they can process at a time and the ability to remember new information long-term.

Memory of the past can also be affected. "As you age, it gets harder to put tags on individual memories, which allows them to be distinctive and easier to retrieve later on," says Tom Hess, PhD, professor in the department of Lifespan Developmental Psychology at North Carolina State University in Raleigh. This change in memory functioning appears to be due to age-related loss of neurons in the hippocampus, the area of the brain partially responsible for establishing new specific memories.

With age, protein deposits may start to form in the brain. The brain naturally produces a type of plaque called amyloid, which normally degrades and is eliminated by the body. Researchers have noticed a buildup of this protein during autopsies on people who had Alzheimer's disease. Up until very recently, it wasn't possible to look at plaque in healthy people, but Park and her team have been able to inject a radio tracer substance into the brain, then use imaging techniques to see whether healthy volunteers have a buildup of amyloid. They've found that between 25 and 35 percent of healthy adults start to have amyloid buildup in their 40s and 50s. Park notes that the plaque is associated with some cognitive decline but that it's uncertain whether it's an early sign or stage of Alzheimer's disease. "Lots of people functioning at a high level have this plaque that's associated with Alzheimer's," she says.

Growing older isn't all bad news for the brain. Every time you learn something new, new wiring gets laid down. The result: more processing power. You can also fight the aging of the brain.

Aging without question has its foundations in genetically determined mechanisms. "But," points out João Pedro de Magalhães, "genetics can be modulated by environmental factors." I'll give you a good example. One of the markers of aging that you'll be hearing a lot more about in this book are telomeres. Telomeres are the tail ends of chromosomes, the structures that carry genes. Every time a cell divides, the telomeres stabilize the cell's chromosomes, but in the process they become shorter. When telomeres become too short, the cell can no longer divide and it dies. This is believed to lead to various aspects of aging, including diminished muscle strength, wrinkles and lowered immunity. How much telomere length really affects longevity—if at all—is still unknown, but many prominent researchers believe it's an important cog in the wheel of life. In 2008, researchers at King's College in London looked at the length of the telomeres in the white blood cells of twins. Some of the participants were very active, while their twin siblings were quite a bit less active. The results of the study showed that, across the board, telomere length was related to activity: the more active the person, the longer the telomeres. When very active exercisers were compared directly to their less active twins, they had telomere lengths that looked to be about four years younger. Here was a case where genetics were the same, but the cells were influenced by differing external factors, in this instance, exercise.
Major Aging Accelerators


Being overweight predisposes the body to heart disease, but that's only one way that obesity can affect longevity and accelerate aging. New research suggests that it also makes cells older on a molecular level. For instance, some of the same researchers that looked at telomere length in active and sedentary twins also looked at telomere length in obese women. What they found was that obese women had shorter telomeres than lean women. If you translated the telomere length into years, the obese women's cells were nine years older than the lean women's. Excess body fat is also thought to cause oxidative stress and is known to promote inflammation of the kind that's been linked to age-related diseases.

Inflammation caused by excessive body fat may also be related to the shrinking of the brain. Gary Wenk, PhD, a professor of psychology, neuroscience and molecular virology, immunology and medical genetics at the Ohio State University and Medical Center, has shown that proteins that are a byproduct of inflammation can cause regions of the brain responsible for memory and learning new things to become smaller. Other studies have shown that older people who are obese have lesser cognitive and memory capabilities and are at an increased risk for Alzheimer's disease. 

Another way that obesity affects aging is by contributing to insulin resistance. Insulin is the hormone charged with ushering the sugar from your blood into cells throughout your body. When you aren't producing enough insulin, or your cells become resistant to insulin's actions, blood sugar rises. People with type 1 diabetes produce no insulin. People with type 2—the kind that is often caused by too much body fat and constitutes about 90 to 95 percent of diabetes cases—are insulin resistant. That is, their bodies don't respond properly to normal amounts of insulin so that sugar doesn't get adequately transported from the blood to the cells. People with type 2 diabetes may even eventually stop producing normal amounts of insulin, which can make the situation worse.
Insulin resistance can shorten your life span and hasten aging in a number of ways: it encourages inflammation, quashes sirtuin activity (sirtuins are enzymes that delay cell death), shortens telomeres and raises levels of compounds called AGEs—advanced glycation end products—that wreak havoc in the body. Besides obesity (and particularly an overabundance of intra-abdominal fat—stored fat that surrounds the organs), a diet high in sweets, sodas and other sugary drinks, white bread, white rice and other processed grains seems to promote insulin resistance. There's a hereditary factor to insulin resistance as well—your genes may make you more susceptible. But you might be able to stave it off for longer, and if you get it, regulate your blood sugar better, with the type of diet you'll find in chapter 3.

While the link between excessive body weight and aging is disheartening given the rates of obesity in this country, it's somewhat more surprising than what has long been known as the number one cause of preventable death: smoking. Besides its deleterious effect on life span, smoking promotes aging in just about every way imaginable. It's known, for instance, that smoking creates free radicals and that it's associated with the development of many age-related diseases, including some that you might not even think would be related: osteoporosis, diabetes and the eye disease macular degeneration. In the obesity study I mentioned earlier, they also looked at the effect of smoking on telomeres and found that it shortened telomere length by a full 18 percent.

It's been known for some time that smoking is linked to dementia, and recently researchers at Kaiser Permanente in Oakland found that it's also associated with an increased risk of Alzheimer's disease. Compared to nonsmokers, people who smoked two packs a day in midlife increased their risk of Alzheimer's by 157 percent. Dr. Lancer will talk more about the effects of smoking on the skin in chapter 4. However, suffice it to say that there's such a thing as "smoker's face," characterized by deep lines around the mouth and eyes and a grayish tint to the skin. Nicotine contracts the blood vessels, decreasing blood flow to the skin and all the other major organs in the body.

There are a few other reasons why it's to your advantage to quit smoking. One is that it makes it difficult to exercise at the pace you need to get sizable anti-aging benefits. The other is that smoking can interfere with sleep. To see just how much, researchers at the Johns Hopkins University School of Medicine hooked up 40 smokers and 40 nonsmokers to monitoring machines and looked at their brain waves as they slept. The smokers spent a lot less time in deep sleep, the most rejuvenating kind of slumber, and a lot more time in the lighter stages of sleep, when it's easy to be awakened—possibly in part because they were going through nicotine withdrawal while they slept. The smokers also reported feeling less refreshed in the morning. (You'll learn more about the importance of a good night's sleep in chapter 5.) Smoking is probably the single worst thing you can do to yourself—it's like lying on a train track when you know that the train is coming. Quitting, on the other hand, is perhaps the single best thing you can do for yourself.
Work, finances, kids' schedules, relationship problems, sick parents, your own health issues—there are so many sources of stress in our modern daily lives. When you experience stress, your body releases powerful chemicals and hormones, including one called cortisol, that prepare your body to fight or flee a perceived threat or danger—the "fight or flight" response. "That response creates a biochemical soup that changes the chemistry of our blood," explains Elissa Epel, PhD, associate professor in the department of psychiatry at the University of California, San Francisco. 

The fight or flight response is beneficial in the short run; it helps us deal with a variety of dangerous situations. After the threat has been resolved, hormones level off and your body goes back to baseline. But if these high levels of stress chemicals persist—as they often do when someone is living a high-pressure life—they can be harmful. Instead of protecting the body, they can cause damage to molecules and tissues and lead to a weakened immune system, acne and other problems, including increased intra-abdominal fat, the kind that puts the body at risk for stroke, heart disease and high blood pressure. The stress response also triggers higher levels of damaging free radicals, inflammation and, in some cases, even spikes in insulin and glucose levels that make the body seem prediabetic. And all of these, not surprisingly, can speed up the aging process.
Prolonged stress can also be extremely harmful to the brain. Studies have shown that persistent stress can cause depression and anxiety. It can kill brain cells and damage the hippocampus, the area in charge of memory and learning (research suggests stress actually shrinks this portion of the brain). When damaged, the hippocampus cannot create new memories or access stored ones as efficiently. And because the hippocampus is part of the system that signals the body to stop producing cortisol, levels of the stress hormone can remain out of control and continue to harm the body.
The effects of prolonged stress can even be seen on a cellular level. Epel's research has shown that people with high stress levels have shorter telomeres, which we know is indicative of whole-body aging.
Managing current sources of stress is a must, but it's also important to realize that the stress experienced in the past can play a role in your present-day well-being too. Research shows that stressful or traumatic life events that you experienced as a child—for instance, losing a parent—can have a powerful and lasting effect. "Really stressful events from childhood can add a couple years to a person's subjective age; they can make people feel older," says Markus Schafer, a sociology researcher at Purdue University. "On the other hand, when people feel in control of their lives and things are going smoothly, they're better able to maintain a sense of youthfulness." 

Whether it's stress from the past or stress in the present that you're battling, it may make it more difficult to fight the physical decline that comes with aging. With my own clients, I've seen those overly affected by stress become overwhelmed and have a hard time living up to their eating and exercise goals. When you're stressed out, a comfy couch and a carton of ice cream become a lot more appealing than getting on a treadmill or having a healthy meal—although both of the latter (especially exercise) are good antidotes for stress. Stress also has a tremendous effect on attitude. It can make you feel negative about yourself and your life; it's hard to appreciate all the good things you have when you're overburdened, tense and pressured. Stress can simply sap all the joy and happiness right out of you.
Getting a Handle on Stress
In this day and age, it's the rare person who doesn't feel stressed in some way. Rarer still is the person who is managing it well. I say "managing" it because it's really not possible to entirely eliminate stress from your life. But if you organize your life more efficiently and have a few go-to ways to relax, you can significantly lower the wear and tear stress has on your body. Here are a few suggestions for living a lower-stress life.

List the major sources of stress in your life to identify the big categories.

Keep a journal for two weeks to identify the more specific triggers. Write down all the situations that make you feel anxious or tense, as well as how you handled (or didn't handle) them. At the end of two weeks, read through your journal. What stressful events can you avoid? Which relationships are making you feel stressed out? Can you improve them, or possibly consider ending them?

If you're constantly pressed for time with a day that's way too full, what in your schedule could you possibly eliminate?

Make sure you are following all the healthy recommendations in this book.

Eating healthfully, exercising regularly, and getting enough sleep can go a long way toward helping you cope with stress.

Make time for daily relaxation. It's important to determine what helps slow your mind and body down. Maybe it's meditation, yoga or working out in the gym. It could be reading, sitting down with a cup of tea, listening to music. Find what helps you de-stress and practice it at least once a day.

Get help if you need it. And I'm not just talking about seeing a therapist, although seeing a therapist can be helpful if you feel that your life is out of control.

Consider enrolling in a stress management program at a local hospital, medical center or community clinic. Someone like a professional organizer or life coach might be able to help you manage your life more efficiently.

If you're feeling overwhelmed, talk to your family, friends, colleagues, boss or even your company's administration. They may be able to help you scale back if you've taken on too many responsibilities.

Have a collection of "emergency stress stoppers" in your arsenal. The American Heart Association recommends these seven ways to calm down.

1. Count to 10 before you speak.
2. Take three to five deep breaths.
3. Walk away from the stressful situation and say you'll handle it later.
4. Go for a walk.
5. Don't be afraid to say "I'm sorry" if you make a mistake.
6. Break down big problems into smaller parts. For example, answer one email or phone call per day instead of dealing with everything at once.
7. Drive in the slow lane or avoid busy roads to help you stay calm while driving.
Aging's Effects on the Body
There are essentially two ways that we age. The first is called primary aging. "That happens at the cellular level and includes attacks on our cells by free radicals, DNA damage and the wear and tear on cells, tissues and organs from constant ongoing chemical and other reactions that constitute metabolism," explains Donald Williamson, PhD, an anti-aging researcher and the John Stauffer McIlhenny Professor in Nutrition at Pennington Biomedical Research Center in Louisiana. "Secondary aging is developing a disease such as cancer, atherosclerosis or diabetes, which can shorten the life span."
Some aspects of aging are obvious. It's apparent, for instance, that the skin changes. Layers within and beneath the skin become thinner, helping to cause sagging and wrinkles—the skin, in a sense, folds in on itself. The skin also becomes less elastic and drier. It grows to be less sensitive to touch, too, and becomes less adept at regulating the body's temperature. Hair loses pigment (the reason we become gray) and hair volume is lost in both men and women.
Body shape can change too. Most people gain fat, and in many women, fat storage shifts from the hips and thighs to the abdomen. This deep intra-abdominal fat is one of the reasons that the risk of heart disease and diabetes in women dramatically increases after menopause. 

One of the more noticeable signs that someone is growing older is the sudden appearance of reading glasses on his or her face. As the lens of the eye becomes less flexible, it makes it harder to focus on objects in the near distance. Vision in dim light also diminishes, and cataracts—clouded lenses—can start forming as early as age 40.
There are also many changes that you can't see, and these changes have an impact on secondary aging. For instance, the thymus, a gland central to the immune system, shrinks, and many of the immune cells decrease in their ability to battle bacteria, viruses and even cancer cells. The heart muscle degenerates slightly, and the valves inside the heart become thicker and stiffer. Arteries are more likely to get clogged with plaque, and blood pressure may increase. The function of most organs declines as well, and cells become less able to divide and reproduce. Some hormone levels rise while others drop, changing the characteristics of many physiological processes such as metabolism and insulin sensitivity. Our sleep architecture—the different stages of sleep—shifts so that we spend less time in deep, refreshing sleep and more time in the lighter phases from which we're more easily awakened.
Significant changes in the muscles, bones and joints start to occur as well. Muscle fibers shrink and the repair of muscle tissue slows, lowering strength, decreasing the rate at which calories are burned and making the body more susceptible to obesity. The joints become stiffer and bone mass is lost, increasing the risk of osteoporosis. The vertebrae can also become more compressed, the reason why many people lose height as they grow older.

The Light at the End of the Tunnel
Just reading all of the above, I know, can cause you some despair. No one likes to think of their body (and especially their mind) deteriorating. But there's room for optimism, because you can really make a difference in the rate at which you age and how susceptible you become to age-related diseases. Everything I describe above can happen, but it doesn't have to: How you live can have a significant impact on how your body ages. In the following chapters, you'll learn about how exercise, good nutrition, skincare and healthy sleep habits actually change your physiology. Your body will grow chronologically older; there is nothing you can do about that. But you can get physiologically younger. Successful aging isn't an oxymoron. By adhering to the advice in this book, you can substantially lower your likelihood of disease, look and feel younger, and stay strong, vital, sharp, active and happy. Work at it and you can even turn back the clock 20 years or more—no exaggeration.
Reprinted from the book 20 YEARS YOUNGER by Bob Greene. Copyright ©2011 by Bob Greene. Reprinted with permission of Little, Brown and Company. All rights reserved.


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