The Longevity Book: Live stronger. Live better. The art of ageing well.

Another thing to consider is that more living people will mean more ill people, and so along with increased numbers of older people we can expect that the cost of healthcare will increase as well. Not just for the government, but for private insurance companies, and for women everywhere. Why women? Because when it comes to caring for sick and ageing spouses, parents, siblings, in-laws, and friends, it is women who are most likely to take on the responsibility of caregiving. Sixty-six per cent of caregivers in the US are female (#litres_trial_promo). In the years ahead, more women than ever before will be called on to be caretakers for ageing partners and relatives, a duty that will cost them in terms of both their physical and financial health.

Women’s caretaking in the United States is valued from $148 billion to $188 billion (#litres_trial_promo) annually. Given that the ability to provide care for others reduces the hours women are able to work by around 40 per cent, the total cost to an individual caretaker over time will be more than $300,000. It is known that long-term caregivers are likely to suffer (#litres_trial_promo) the ill effects of stress, and are more likely to retire (#litres_trial_promo) early with reduced pensions due to their reduced work hours.

The forecast for the silver tsunami is that it will affect all of us, and the impact will be personal and national, physical and emotional, economic and social and political, even environmental. Our planet will also pay the price as natural resources are stretched beyond limits to support so many more lives.

Did that forecast just throw a spanner into your excitement about living a longer life? Well, I urge you to take this information and add it to your own personal equation of how you’d like to proceed as an ageing human, and specifically, as an ageing woman – and then do your best not only to appreciate this extra time, but also to learn as much as possible about caring for yourself in the very best way that you can, and to encourage the loved ones that you are taking the journey with to care for themselves as best they can. I believe that is our smartest strategy moving forwards. It is the only strategy, really.

With the awareness that this wave is on its way, the most important thing we can do for our families and ourselves is to be strong enough to surf it.

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SINCE SUCH EXTENDED LIFE spans are unprecedented, it makes sense that the study of the effects of longevity is also still in its infancy. The branch of the primary US agency dedicated to the research and understanding of ageing was born around the same time that I was, in the early 1970s. It was only in 1974 that the National Institute on Aging (#litres_trial_promo) (or NIA) was established, one of the twenty-seven institutes and centres that make up the National Institutes of Health (NIH), the US’s federally run medical research institute.

The NIA funds research aimed at understanding ageing and improving healthy living as we age. It is also the primary federal funder of Alzheimer’s research (#litres_trial_promo), which consumes much of its approximately one-billion-dollar budget for research grants (#litres_trial_promo) (1/400th of the total NIH budget is dedicated to funding ageing research). Some of that budget was spent in 2007 to kick-start the emerging field of geroscience; the NIH gave the Buck Institute, a nonprofit biomedical research center, $25 million to study ageing (#litres_trial_promo) and its link to chronic diseases.

When we were travelling across the country in November and December 2014 to learn about the science of ageing, we met with a group of researchers who were in the midst of publishing a collaborative paper called “Geroscience” (#litres_trial_promo) (you can look it up and read it online in the journal Cell if you like). Their paper made a compelling argument for a new, interdisciplinary approach to ageing research.

Its authors are a mix of highly regarded scientists. Some, like Dr Brian Kennedy at the Buck Institute, lead research initiatives for nonprofit organizations that study ageing; others, like Dr Elissa Epel at the University of California, teach and conduct research at major universities; and still others, like Dr Felipe Sierra, the director of the Division of Aging Biology at the National Institute on Aging, hold leadership positions at government-funded entities. The publication of this paper marked the first time that scientists from the private sector, academia, government, and independent organizations came together to collectively investigate a new way to study ageing. It also marked the first time that scientists from across a range of disciplines – from cell biologists to geneticists, endocrinologists, pharmacologists, and mathematicians – collaborated on this common goal.

And the authors of the paper suggested something revolutionary: that future research should approach the various diseases of ageing as having a single shared root cause – ageing itself.

THE OPPORTUNITY OF GEROSCIENCE

The field of geroscience aims to understand the relationship between ageing and age-related diseases. The word root “gero” is derived from the name of the Greek god of ageing, Geras. In classical Greek mythology, most of the gods were represented as young, strong, and beautiful human-like creatures, but elderly Geras was depicted as shrivelled and small. While he may not have been as buff as Zeus, Geras – which translates (#litres_trial_promo) to mean “gift of honor”, or “privilege of age”, or “reward” – had other attributes to offer. Because as youth flees, we gain honour, courage, wisdom, experience, and other rewards.

The term “geroscience” feels apt as we study the new science of getting older, as Geras offers the perfect metaphor for the human relationship with ageing: a fear of physical weakening coupled with the awareness that without years, without experience, the gifts of a life well spent cannot be fully realized. Today, geroscience is attempting to reconcile these two views by investigating how we can remain strong and vital as we age.

According to geroscientists, ageing is the biggest single risk factor (#litres_trial_promo) for chronic illnesses like cardiovascular disease, cancer, type 2 diabetes, osteoporosis, and neurodegeneration (including Alzheimer’s). For decades, medicine has been studying the chronic diseases related to ageing separately instead of collectively. By looking at heart disease as distinct from cancer as distinct from Alzheimer’s, we miss a valuable opportunity to understand what they might all have in common. The radical question posited by the field of geroscience is: What if there were a different way to understand the process of ageing and, in doing so, alter our rate of ageing?

Dr Gordon Lithgow, an expert in ageing and genetics who is the principal investigator and director of the Buck Institute’s Interdisciplinary Research Consortium (#litres_trial_promo) on Geroscience, explained to us how the past revelations that have lengthened our life spans may mirror today’s discoveries about ageing. In the nineteenth century, life expectancy increased when scientists realized that many of the diseases that were killing people had a common cause. Tuberculosis, smallpox, and the flu may have looked differently and behaved differently, but they were all the result of coming into contact with tiny little organisms we couldn’t yet see. The discovery of bacteria and viruses allowed scientists to develop effective treatments for the illnesses they cause.

The awareness sweeping science today is that the same principle may be true for the diseases of ageing. Heart attacks, cancer, and diabetes all look different and behave differently, but if we can understand their common cause, we may be able not only to live longer, but also to age with more of our health intact.

WHAT’S THE DEAL WITH STEM CELLS?

One new area of medicine that’s received a lot of attention recently is regenerative medicine, which uses stem cells to help heal and repair damaged and diseased organs. There’s been a lot of excitement about the potential of stem cells to heal, as well as much controversy about how they are harvested.

There are two main classifications of naturally occurring stem cells: embryonic stem cells and adult stem cells. Embryonic stem cells have tremendous value in medical research because they have the ability to divide and become other types of cells. Embryonic stem cells come from human embryos, which contain cells that can differentiate into one of three kinds of primary cell layers (#litres_trial_promo) (ectoderm, endoderm, and mesoderm) that have the potential to turn into any kind of cell in the body, from skin to muscle to nerve. But the practice of harvesting embryonic stem cells is controversial.

Then there are adult stem cells, also called somatic stem cells, which live in the tissues of our organs. We now know that adults have stem cells (#litres_trial_promo) in our brains, bone marrow, blood vessels, skin, teeth, heart, gut, liver, ovaries, and testis. These powerful cells are always at the ready to heal and repair, and have the potential to morph (#litres_trial_promo) into other types of cells needed by the organ. Stem cells can remain dormant for a long time until they are needed to make more cells, or until a disease or injury incentivizes them to spring into action. Some adult stem cells can also be activated (#litres_trial_promo) following exercise (as if you needed another reason to get your body moving!). The challenge of treating disease with adult stem cells is that adults have few stem cells in our tissues, and even once those have been harvested and isolated in a lab, growing more of them isn’t easy.

Enter induced pluripotent stem cells (iPSCs). The 2012 Nobel Prize (#litres_trial_promo) was awarded for the discovery that mature cells – normal adult cells, like skin cells – can be reprogrammed to become immature, embryonic-like cells capable of developing into specialized cells. These time-machined cells can then be used for treatments throughout the body. Since this breakthrough, researchers around the globe have been creating iPSCs and encouraging them to divide to become skeletal cells, epithelial (tissue) cells, and cardiac cells to see if they can form new bones, skin, and hearts.

What’s so exciting about iPSCs is that they provide a way around the embryo-harvesting issues and ensure a scalable supply of adult stem cells for research and treatment. Not only that, but these cells can be derived from specific people (#litres_trial_promo), and so it will be your cells that are potentially made into the new cardiac cells you need after a heart failure, or your cells that make the dopamine cells you need to replace those lost in Parkinson’s disease.

Over the coming years, we will be hearing more about the future of regenerative medicine and transplants. Scientists are very optimistic about the therapeutic potential of stem cells.

Think about that for a moment. If ageing is the common cause of those illnesses, and we can increase our understanding of ageing at the cellular level (#litres_trial_promo), we may be able to live with strength and health until we die quietly in our sleep. Our bodies will weaken naturally, and ageing puts us at risk of a host of diseases, but a risk factor is not a diagnosis. It’s a call to action, to arms, and to attention. Knowing the risks can empower us to become the architects of our own strength and resilience.

HOW AGEING IS STUDIED

We are ageing in a time when science is committed to and compelled by the question “What is ageing?” The science of understanding ageing takes place in laboratories and meeting rooms, at desks and with the help of technology. Study participants may dutifully take medications, try different ways of eating, of moving, of sleeping, or just give up their privacy and answer loads of questions, all so that we can better understand how ageing affects our bodies. The test groups for these studies range in sample size from a hundred people to hundreds of thousands of people. When we see the results of the latest research plastered all over social media or mentioned in a morning news show or even announced in the headlines of newspapers, it’s important to keep in mind that every study varies in terms of how it collects its data. Data can be influenced by how many participants are included, and also by how well a study is designed and the elements for which its researchers are controlling – factors ranging from time and temperature to gender and age may affect a study’s accuracy.

One type of research method is the observational study. Observational studies assess how the choices people make affect their wellness. Some of these studies, like the Framingham heart study (see here (#litres_trial_promo)), are longitudinal – they track participants over a sustained period of time. Longitudinal studies (#litres_trial_promo) can last for decades, and they have been very useful in helping us understand ageing.

Observational studies can also examine a cross-section of people (#litres_trial_promo) and compare them with one another to see how their choices have influenced their health. For example, one cross-sectional study compared older people with similar health profiles to determine the effects of vitamin D deficiency (#litres_trial_promo) (answer: it can put you in a lousy mood as well as impair your ability to think clearly).

Some studies are less about observing, and are more about getting involved. An interventional study (#litres_trial_promo) gathers groups of people to study for comparison. Researchers ask one group to implement a specific behaviour in order to observe its impact on health, and use the other group as a control for comparison. For instance, when researchers wanted to understand how the intensity levels of physical activity would affect memory, they organized sixty-two healthy older people into three groups. Over the course of six months, one group performed medium-intensity workouts, one group performed low-intensity workouts, and the other group did not work out at all. The study found that any exercise had great benefits (#litres_trial_promo) for memory and brain volume, with little difference between the low- and medium-intensity groups.

When researchers study ageing, they don’t only observe humans, they also turn to human cells, animal cells, bacteria, mould, and fungi. They experiment on lab animals (and sometimes wild animals), from sponges and worms (#litres_trial_promo) to mice and monkeys to naked mole rats (#litres_trial_promo). By examining and manipulating genes from other animals, scientists can gain insights into the human ageing process. Although worms look nothing like human beings on the outside, internally, like flies, they have many genes and biological mechanisms (#litres_trial_promo) in common with us. And just like people, worms and flies age, albeit at a much faster rate. Within a year’s time, many rounds of testing and learning can take place on worms and flies, whereas watching humans age in observational studies takes a human lifetime – more time than one scientist has on her hands.

Comparative biology can also yield important insights. Naked mole rats, which are somewhat terrifying-looking mouse-sized rodents, live seventeen to twenty-eight years, while common mice and rats live only three to five years. Why the disparity? By comparing similar mammals (#litres_trial_promo) with very different life spans, scientists may be able to identify the specific genes that make some live longer than others.

If one direction of learning shows promise when it comes to increasing the length of life – and the length of a healthy life – scientists will apply and reapply methodologies that are more and more complex, ultimately testing medications or treatments on humans to determine their safety. At each step, they must evaluate the efficacy of their methods. Just because manipulating a certain gene or pathway or hormone makes a fly live longer doesn’t mean it will do the same for a mouse, let alone a human.

And just because it works for a man doesn’t mean it will work for a woman, as we will soon discuss.

IS IT POSSIBLE TO GROW OLD WITH HEALTH?

Life expectancy doesn’t tell us how long a being might live under the best of conditions. It tells us how long a being might live while taking into account the reality of its environment. We can give science a lot of credit for doubling our life span, but we can’t give doctors all the responsibility for keeping us healthy.

Your genes create the basis for your health. The environment you live in and the lifestyle choices you make every day have a massive impact on how you age, what makes you sick, and how your body heals. As we grow older, weakening is inevitable and becoming strong is a choice. Diseases of old age are not necessarily a given for any one of us. I think it’s always more challenging to make new choices or try out new behaviours if you don’t understand the “why” behind them. Advice like “eat healthfully” or “exercise every day” doesn’t really mean anything to me in a vacuum. That’s why the information in this book is so important to me. Without context, how can any of us be expected to understand why we should eat more vegetables or why strength training is a big deal for women? We know from being avid consumers of media that certain things are “good for us”, but we may not fully understand why.

So let’s do our best to learn these things. Let’s try to better understand how our choices influence our health at the cellular level, and how the changes in our cells are what affect our health as a whole and, in particular, our health as we age. We can become better advocates for our own health. It all starts with learning the facts.

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FACT: WOMEN LIVE LONGER than men. A baby girl born in the United States in 2010 (#litres_trial_promo) had a life expectancy of eighty-one; for the baby boy next door, that number was seventy-six. That’s a five-year gap, enough to make a person really curious about why this might be the case, especially when you consider that this is true around the world, too. Country by country, life expectancies vary (due in part to variables like availability of clean water, access to healthcare, and stability of the region), but the world over, the women’s life expectancies (#litres_trial_promo) are always greater than men’s.

In the United States, over the course of all that longevity, women use more healthcare services (#litres_trial_promo) and take more prescription drugs than men do. Researchers at the Mayo Clinic made headlines a few years back when they announced that nearly 70 per cent of Americans (#litres_trial_promo) take at least one prescription drug daily. They also reported that, as a whole, women and older adults receive the most drug prescriptions. As people get older, they are prescribed more pills to take, not fewer, and the quality and accuracy of those medications has a direct impact on health. The more medicines lined up in your bathroom cabinet, the more important it becomes that you are taking the right medications, in the right doses, at the right times.

Health and healthcare are inextricably bound together. Every time you go to the GP surgery, every time you pop a pill, you are relying not only on your doctor and your pharmacist, but also on medical schools, on drug companies, on research labs, on individual scientists – and their assumptions about women, and their awareness of the latest research about women’s health and women’s bodies.

A lot of people hate going to the doctor, and I get it. Hanging out in a waiting room on your lunch hour or having blood drawn when you’re running late for another appointment is not exactly fun. But I take going to the doctor very seriously. When I’m sick, I make an appointment. And when I’m healthy, I make appointments, so that I can avoid getting sick for as long as possible. I want to understand where my health is now so that I have a framework for comparison for later. I want to use medicine as a preventative tool for my health as I age.

And researchers are discovering that this habit of mine might actually be tied to female longevity. Women are more likely to visit the GP (#litres_trial_promo) than men and this may help us to live longer. So do the other healthy choices that, as a group, women make (#litres_trial_promo) more than men do, like not smoking. Fewer women than men smoke, which cuts our risk profile for numerous diseases. Men also drink more than women do. Women are more careful about their nutrition, and taking care of food needs helps bolster strength and longevity. And women are less likely to take risks. Fewer risks equals fewer injuries, which equals greater health: unintentional injury is number three (#litres_trial_promo) on the Centers for Disease Control and Prevention’s mortality charts for men, and number six for women (#litres_trial_promo). Women also value friendship, love, and connection. We are social beings who invest in our families and in our communities and in our relationships. All these choices contribute to a longer life.

But female longevity isn’t just about our choices. Among primates like chimpanzees (#litres_trial_promo), females live longer too, and monkeys don’t make doctor’s appointments. So why do females enjoy a longer life span? Some scientists are looking for answers that are rooted deep within the genetic coding of our cells. The cells of men and the cells of women are not the same, and what makes your cells unique affects everything about you – including how long you live.

THE OLDEST WOMAN IN THE WORLD

Today, life expectancy is twice what it used to be, but it may still be forty years shy of the maximum human life (#litres_trial_promo) span, which most scientists believe to be about 120 years old.

They base that opinion on people like Jeanne Calment (#litres_trial_promo), the oldest woman who ever lived. Jeanne was born in France in 1875 and passed away in 1997. When she was a year old, Alexander Graham Bell invented the telephone. When she was thirteen, she met Vincent van Gogh. When she was eighteen, the Wright brothers flew for the first time. She lived through two world wars, saw infections thwarted by medicine, and witnessed the development of the Internet and contemporary medical technologies.

When she was ninety, a lawyer who was not yet fifty offered to pay her every year if he could take over her home when she died. She agreed. He died at seventy-seven, and Jeanne kept on going. She lived by herself until she passed away at the age of 122.

WHAT DOES IT MEAN TO BE BIOLOGICALLY FEMALE?