Читать книгу The Longevity Book: Live stronger. Live better. The art of ageing well. - Cameron Diaz, Cameron Diaz - Страница 15

WHEN I WAS A child, I loved to spend as much time as I could with my grandparents. My grandmother was my hero. She was seven years older than my grandfather, and she was a powerhouse.

My grandmother was my ideal of strength and ability. She basically maintained a full working farm at her house, raising her own livestock and tending a thriving garden. She didn’t drive, so when she needed more feed for her chickens and rabbits she would set out on foot. She would walk to the feed store, about a mile away, and carry two ten-pound sacks of feed, one in each hand, on the walk back, even in the heat of the summer. If she wanted to haul more, she would bring a wagon. As a child, I remember asking her why she carried such heavy bags so far in the scorching heat. She would say, “Because I like it, and because it keeps me strong.” Her answer was so awesome to me, and I think of it every time I am pushing myself to go farther, to work harder, to try a little bit more.

When that little voice in my head says “Stop! Why? Enough!” I say, “Because I like it. Because it keeps me strong.” That is the legacy my grandmother left me, and I thank her for it each and every day.

My grandfather, although he lived in the same house with my grandmother, had a very different lifestyle than she did. His job required him to sit in an office, he smoked and he chewed tobacco, and he enjoyed red meat more than his vegetables. When I was eight years old, he had a heart attack and passed away. He was only sixty-three. Meanwhile, my grandmother lived to be nearly ninety. She stayed vital into her seventies. Hauling feed, along with all of her other regular chores, kept her strong and resilient.

But even hard work cannot always protect us from illness. At seventy-three, my grandmother was diagnosed with breast cancer, which is now considered to be an age-related disease. She also developed an irregular heartbeat. So she underwent two major surgeries to save her life – she had a mastectomy and she had a pacemaker implanted. During her recovery she came to stay with us, and I spent that summer making meals, helping her bathe, and reading to her as she drifted off to sleep. She had a bell that she would ring in the morning, and I would come and take her to use the bathroom. For the first time in her life she was relieved of her strenuous chores and her day-to-day responsibilities – and she liked having her family close by, helping her, caring for her.

When she got better, she went back to her active lifestyle, gardening and working around the house. But she was getting older and getting tired. She didn’t have the same energy that she’d had abundantly before her battle with cancer. And so, after a while, she decided that she had worked hard enough. She didn’t want to take care of the animals and the garden anymore. She wanted a less strenuous life – and so my mum and dad asked her to move in with us.

At first she remained active, walking around the house and hanging out in the kitchen. But as time went by she began to rely more and more on our caretaking, and I watched her go from functioning mostly on her own to relying on me to hold her up as she scuffled with her walker. She went from sitting with the family in the living room to spending most of her day lying down and asking everyone to come visit her in her bedroom. She stopped eating her meals at the table and requested to have them in bed. As her effort declined, so did her health. I could understand how at her age she might want a rest from her backbreaking chores, but it was hard and confusing for me to watch her change. She was never the same again.

I was just a kid, but her changes imprinted on me how fragile even the strongest person could become. I saw how important it is to work as hard as we can, for as long as we can, if we want to age with strength.

WHERE DID YOU LEARN ABOUT AGEING?

I witnessed different kinds of ageing when I was a kid, and it taught me a lot about what I might expect for myself. Where did your first ideas about ageing come from? Many of us learned about what ageing looks like by watching our family members grow older. Were your grandparents healthy and active, or did they always seem old and infirm? How about your parents? The attitudes we absorb about what it means to age and what life is like for the aged will affect our own ageing process.

Your birthday does not determine how long or well you will live. You may share the same birth year as someone else, or even the same birth date and birth mother, but the way that you live will affect the way that you age. While there are broad age-related changes that apply to everyone, for an individual, biological age (how healthy you are on the inside) is a more important indicator of health than chronological age (the number of years you’ve been on this planet). The ageing of our cells is the true measure of how old we are.

Many different factors influence the way you age. There’s the genetic component, of course, which we are reminded of every time we give our family medical history at the GP surgery. But genes aren’t everything. While some research ties longevity to the genes we inherit from our parents, our choices, our environment, and our attitude have just as powerful an impact on how healthfully and long we live. How old we truly are – in a biological sense – is a combination of these factors.

My grandmother’s habit of hauling chicken feed on hot summer days at the age of seventy is a good example of how the number of years we have lived and the level of health and independence we enjoy do not always correlate. Each of my grandparents aged in a way that was purely of them, not only genetically but also an extension of their personalities and how they lived their lives. When I was growing up, I was aware that my grandmother was seven years older than my grandfather. But now I understand that biologically, deep within her cells, she was probably a lot younger than her chronological age.

Nobody can resist the pull of time forever, but the longer we are able to find the energy and the reserves to keep pushing ourselves, to believe that ageing with strength is possible, the stronger and more self-reliant we are likely to remain.

AGEING IS PERSONAL

Nature gives you the genes you have at birth. As an adult, the environment you live in and the lifestyle choices you make help determine how you age and how you feel. Since where you live and how you live is personal to you as an individual, so is the way that you age. That’s part of why the study of ageing is so complex: there is no one-size-fits-all answer. You start out as a cluster of cells that develops in response to the genes that are coded deep within your DNA, which are also known as your genotype. Your genotype is what you inherited from both of your parents, basically the blueprint that nature has used to create and build you. When infants are born, they are immediately weighed and measured. This is a useful marker for health, because babies can be compared by height and weight. But by the time we are toddlers, our environments have already begun to affect our development as much as our genes.

Even in our earliest years, our environments influence our health. Growing up in a household that is very stressful, for example, will affect your genes differently than if you are raised in a home that is calm and secure. Alexandra Crosswell, a research scientist at the University of California, San Francisco, whom we saw give a rousing lecture about her work, has been studying a group of breast-cancer patients to investigate the ways exposure to stress during our childhood years can affect our health as adults. She found that participants who had experienced abuse, neglect, or chaos within their home as children showed biomarkers for inflammation later in life that are linked to negative outcomes for health and well-being.

Life has a real effect on our health. Stress and trauma and smoking have an effect; love and safety and eating green vegetables have an effect. But these factors don’t just have a short-term impact on our well-being; as Dr Crosswell’s study suggests, they can also have a very powerful, long-term influence. How is this possible? Because your lifestyle – the experiences you have, the places you live, the choices you make – can actually alter the way your genes are expressed.

Some genes are like light switches that can be flicked on or off by experience. Good nutrition, fitness, and low levels of stress may help flick off some of your genetic predispositions to disease, while smoking, eating poorly, and being sedentary may activate on your genes for disease. And the genes that have become altered as a result of your lifestyle can actually be passed down to the next generation. That means that the DNA each one of us receives from our parents is influenced by the lifestyle of not only our parents, but also our grandparents and our great-grandparents and our great-great-grandparents. The study of this biological phenomenon is called epigenetics. A relatively new branch of the field of genetics, epigenetics suggests that the effects of life on our genes can be passed down like family heirlooms.

My grandmother’s active nature affected my attitude about ageing. But the effects of her choices on my health may be even deeper than attitude. If she was especially active when she was young, then those genes could have been passed on to my mother, and to me. If I wind up enjoying a long life, with great health and strength as I get older, will that be because my grandmother was strong and fit in her youth? Or will it be because I am actively learning about health and my body, and doing my best to take care of my physical and emotional self? If I age well, will it be because of me? Or because of my genes? In the end, it will be both. My genotype has been affected by the life I’ve lived. This mix of nature and nurture has created what is known as my phenotype – the “observable” characteristics that are the result of the interaction between genes and environment.

My phenotype, and yours, includes physical traits like hair and eye colour, as well as behavioral and personality traits such as whether or not you gain weight easily or how anxious or laid-back you tend to be. We all have a phenotype, but each phenotype is distinct: nobody else in the world has your phenotype. Even if you’re an identical twin – which means you share a genotype with your sibling – your phenotype is still unique. That’s because it’s impossible to live the same exact life, making the same exact choices and having the exact same experiences as anyone else. As we age, our phenotypes have a significant impact on our health and on our likelihood of developing the diseases of ageing. Genotype is nature. Phenotype is nature and nurture mixed together.

As we age, our bodies will undergo a series of shifts and changes, detectable at the cellular level and visible at the surface level. And these changes will not affect you and your friends or your siblings in the same way.

AGEING THROUGH THE DECADES

Your body has always been changing, and that’s because it is an amazing machine that can grow, heal, reproduce, and, yes, age. You may currently be at an age at which you have witnessed enough changes to finally accept that over the rest of your lifetime, your body will shift a few more times. The rate at which we age and the shifts that accompany ageing are unique for every person. We will all age, but we will not all experience ageing the same way. Yet there are, generally speaking, some changes that will affect us all.

The changes of ageing began when you were fairly young, because in organisms from worms to humans, the onset of ageing happens around the time that sexual maturity is reached. That means that right when your boobs were at their perkiest, when you weren’t thinking about getting older except maybe to turn twenty-one so you could get into bars and clubs legally, the ageing process was starting to take hold deep within your body.

The changes first began to show up in your tissues and organs around the time you got that legal ID. The tissue of your lungs, those gorgeous balloons that give us breath, began to lose their elasticity and the muscles that surround and support your ribcage started to shrink. That means that with every breath you have taken since you were of legal drinking age, you inhaled just a little bit less oxygen. Of course, you probably never noticed. Perhaps because, according to some research, cognitive skills also begin to slip after age twenty-four.

In your thirties, the changes taking place inside your body are ones that you begin to see and feel. For instance, you begin to lose mass in your muscles, reducing their function, partially because you have fewer growth hormones and less testosterone than you did a decade prior. Around the same age, the number of cells in your kidneys decreases and the organs actually become smaller as a result, to the point where they filter blood less efficiently. At around age thirty you will have reached peak bone mass, making it extremely important to build up your bone mass before the age of thirty-five through nutrition and fitness. (More on that in Chapter 9.)

As your forties come into focus, you might find it tougher to read the menu in a dimly lit restaurant. That’s because the lens of the eye thickens with age. Once you’ve secured yourself a stylish pair of reading glasses you may also notice some other signs of ageing: grey hair due to decreased melanin production in your hair follicle cells, and fine lines, due to decreased collagen production in your skin cells. Your back may begin to ache, a result of tight muscles, herniated discs, or just too much sitting. And if you have that extra glass of wine at the restaurant? Your hangover the next day will be a lot more unpleasant than it was in your twenties or your thirties, partly because your liver can no longer process alcohol as effectively as it used to.

The time of life when we are obviously ageing and aged – not the subtle shifts that begin to age us in our twenties, but the cold, hard realities of ageing that you wake up to in your fifties – is known as senescence, or “to grow old”. The word “senescence” comes from the Latin spirit of old age, Senectus, who also loaned us the root for the words “senescent”, “senile”, and “senator”. During this stage, more and more of your cells begin to show the impact of your decades of living – these are called senescent cells. During senescence, the effects of ageing can be felt more readily on the surface; as time goes on, and more and more cells become senescent, you get older and older (we’ll discuss this in more detail in Chapter 6).