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Over the last hundred and fifty years, the human lifespan has doubled from 40 to 8- years. But the quality of life for the majority of our eldery folk has been severely impacted by chronic disease. It seems as if, by challenging the biological clock, we’ve run up against a limit to healthy aging that makes physical breakdown inevitable.

However, that’s not what we see in nature.

In this second part of our multi part series, we investigate aging in nature in order to understand whether illness in old age is inevitable in humans. 

In Nature, Ill Health in Old Age is Not Inevitable

In the interest of learning about alternatives to the aging process humans experience, in recent years, biologists have studied the healthspan mechanisms of animals and plants that don’t age in the same ways that we do. These species may die of a disease or an accident, but, unlike us, they barely suffer senescence (biological aging). From unicellular and multicellular organisms to vertebrates, some species enjoy plateaued existence, even as they age, until the very end of life.

Take the Great Basin bristlecone pine – a long-living tree species found in the taller mountains of California, Nevada, and Utah. One member of this species has been around since the very early days of recorded history. 

This tree is 5067 years old. 

Another example of extreme health span is Turritopsis Dohrnii, also known as the immortal jellyfish. Found in the Mediterranean Sea and in the waters of Japan, these jellyfish are able to undo their development, aging not towards death but rather backward to their youth, and begin a new cycle. 

If that were an option for humans, many would sign up for that in a heartbeat! It is one of the few known animals capable of reverting completely after having reached sexual maturity and, theoretically, this process can go on indefinitely. 

Mother Nature is not against healthy longevity; she is just extremely selective of it. There’s still a long way to go from where we stand now to healthy longevity in humans, but gaining a better understanding of the very rare conditions when it is made possible is a step in the right direction.

We find extreme healthy longevity in some clams, turtles, lobsters, sharks and other animals. One of the secrets to their longevity is that they mostly manage to avoid the accumulation of damage overtime. 

But, what about species that are biologically closer to us? Are there cases of mammals that age and maintain health simultaneously? 

If we are able answer these questions, it would take us another step toward understanding the possibility of improving human health span, and making it possible.

Good Health in Old Age is Possible in Animals, Too

Turns out mammals can age healthily too. Nature has provided an astonishing example of health in old age in the form of a wrinkled rat, and the mysteries of its biology have puzzled scientists for decades. While this particular species may not be considered “cute” by the human critic, there are many reasons to admire and envy the mammalian world champion of healthspan – the naked mole rat. It lives in a good reproductive and health state for the most part of its 30 years of life – outliving rodents of its size ten times over. The naked mole rat is a unique creature in many ways; going above and beyond hygiene standards when compared to most other mammals. In their tunnels, they delineate a separate toilet area, where feces and urine get stored. 

Yet, the characteristic perhaps most interesting for us in terms of healthy longevity research, is that naked mole rats are biologically at a risk of accumulating cellular damage as a result of metabolic processes similar to ours. The difference is that they seem to have found a way to overcome it. They are virtually resistant to cancer; there have been fewer than half a dozen recorded cases of cancer in the heavily studied naked mole rat. Even more interesting is the fact that, for them, the biological “cost of operating a life” does not rise exponentially with age. Rather, it has only negligible negative effect on their health. 

Implications for Humans

How is it possible for the naked mole rat not to accumulate the ‘costs of operating a life’ in the same way that humans do? In 2017, scientists working for Calico, an Alphabet (Google) research and development company whose public mission is to devise interventions that enable people to lead longer and healthier lives, presented evidence that the naked mole rat is time-resilient in more ways than we knew. The mortality of the naked mole rat, they say, does not increase with age. 

With discoveries like these, we are one small step closer to understanding the biology of healthy longevity. While, like naked mole rats, we, too, have figured out that separating the toilet from our bedroom is important, humans don’t have the longevity genes they do. 

The next question has to be, are there cases of extreme health span in humans?   We’ll explore the answer to that question in Part Three of this multi part series.

For Part Three: Is Living a Long Healthy Life Luck of the Draw? CLICK HERE

For Part One: Is Living a Long Healthy Life Luck of the Draw? CLICK HERE

In 1944 Polish candy factory owner Yisrael Kristal lost his wife and two children after the family was transported to Auschwitz concentration camp. Kristal survived, making it though the brutal 1945 death march. After the war he went back to his home town where he met fellow Hholocaust survivor Bat Sheva.  They married and began a new life together, The couple married, started a family, and opened a new candy factory in Haifa. Yisreal lived on to became the Guinness world record oldest Holocaust survivor in 2010, and lived to see his great grandchildren thrive in Israel. 

Throughout the most part of his long life, Yisrael enjoyed good health. He died surrounded by his extended family in 2017, just 5 days short of his 114th birthday. Kristal was a middle aged man when he lost everything, and in the seven decades that followed the war, he got to start a new life and live it fully. 

Yisrael Kristal 
Taken from jpost.com (photo credit: COURTESY OF FAMILY)

Living Longer But Not Healthier

Celebrating life with such healthy longevity is a rare individual achievement. Yet, as a species, we have made extraordinary improvement in the longevity stakes over the 150 years. During that time the average global lifespan has more than doubled.  A two-fold increase in longevity in a blink of an eye on the evolutionary time scale, is a remarkable human achievement. However, the extended human lifespan has brought with it some major adverse effects. Consequently, for most of us, an increase in lifespan iis not equal to an increase in healthspan. 

Credit: OurWorldInData.org

As we age, put chances of getting sick increase. In fact, the risk of suffering from such conditions as cardiovascular disease, cancer and Alzheimer’s disease goes up exponentially with every year we add to our lives. Arthritis, osteoporosis, type 2 diabetes, and many other chronic diseases are all associated with aging. In 2020, more than half of Americans 65 and older are being treated for multiple chronic conditions. A typical chronic combination of conditions is diabetes together with high blood pressure and a heart condition. 

A 2011 study by the world economic forum projected that by the year 2030 the cost for treating chronic illness worldwide would exceed 47 trillion dollars. The rising cost of managing the ill health of old age is devastating and the impact on the quality of life of a chronically ill individual is immeasurable. 

Longer lives have come with a dire unintended downside. In extending lifespan we hoped for a commensurate better quality of life. Instead, it seems we have stretched our limits beyond sustainable biological longevity. As a result, ill health in old age, and the economic healthcare burden that can bring economies to their knees, is inevitable. 

Or is it? 

In this article series, we explore breakthroughs in longevity science and biotechnology that suggest it is time for us to rethink the notions that extended lifespan and health are mutually exclusive. As technology advances and we learn more about biological aging, there are more reasons to be optimistic that good health over most of a long life may be possible.

 Imminent even. 

Why Do We Get Sick When We Get Older?  

Longevity and health are an age old human desire. Every culture has its tales of longevity outliers. In the Bible, Methuselah lived to the ripe old age of 960, with many Bible patriarchs living well into the multiple centuries. Yet, for millions of years the average life span was between20 and 30 years. A few millennia ago it began to gradually climb until it reach into the early 40s in the second part of the 9th century.

The burning question driving scientists globally is, with the rare exception of centenarians, could the reason we get sick when we age be that in doubling lifespan we have broken some irrefutable law of biology?

What we do know is that risk of suffering from cardiovascular disease, cancer, Alzheimers, arthritis, osteoporosis, type 2 diabetes, and many other chronic conditions goes up as we get older. These illness are very different in nature from the infectious diseases that contribute to mortality in the early parts of life. 

Is There a Common Root Cause to the Diseases of Old Age? 

The answer, growing insights from longevity science tell us, is the process of biological aging. 

Gerontologists refer to it as senescence. Simply put, it is a gradual and ultimately fatal deterioration of function that results from accumulated damage in the body. This appears to be a deadly side effect of essential metabolic processes in a biological economy that from middle age on suffers from diminishing garbage disposal and repair resources. 

Think of this as biological operating expenses that rise exponentially from middle age until,l eventually, running the business of staying alive becomes unsustainable. In the past we didn’t live much beyond middle age. 

Age related illnesses came along as we took evolution into our own hands and deliberately ventured humanity to new frontiers of longevity. 

Does that mean that ill health in old age is inevitable? Or can a biohealth hacking focus allow us to live longer AND healthier lives? In Part Two of this multi part series we search for answers.

For Part Two: Is Living a Long Healthy Life Luck of the Draw? CLICK HERE