Everyone past a certain age has experienced it; an unexpected flash of silver, the mad dash for the tweezers. The realisation that your vitality is not sprung from an infinite well. Throughout history, humankind has only ever known mortality as a downward slope, the vestiges of youth fleeting and irretrievable. But will it always be that way?
Science fiction offers us a glimpse at futures where eternal youth is the norm. Whether by uploading to a digital consciousness, inhabiting a synthetic body, or contracting viral technology that turns you into an immortal superhuman, the genre has conceptualised many fanciful ways to cheat death.
And though it may sound far-fetched, even now people are freezing themselves in liquid nitrogen, in the hopes that they’ll one day be revived by a world possessing such technology. In the harsh deserts of Arizona, hundreds of human popsicles lie in wait, hoping that they may yet have the last laugh.
Whether or not life-prolonging tech does come to fruition, the reality is that it won’t be happening anytime soon. However, that’s not to say we won’t see any improvements to our lifespan. In fact, current medical research is making huge strides in combating the effects of aging, with the goal of achieving not just life extension, but health extension.
Aging as a Disease
When looking at the effects of aging, researchers approach it as they would any other disease—by studying the symptoms and its underlying causes. External indicators like grey hair, wrinkles, or reduced mobility are all signs of internal processes breaking down. Cells become less effective and tissue wears out over time. While the exact cause of aging is unknown, current theories attribute it to a variety of factors which fall into one of two broad groups: damage-related causes and program-related causes.
Damage-related causes could be thought of as your body undergoing wear-and-tear. From background radiation or environmental chemicals, to diet, disease or injury, it all takes its toll, causing genetic damage that inhibits your body from functioning properly. On average, 0.6% of the DNA in human heart cells is damaged every year, and over several decades of accumulation this can reduce the muscle’s effectiveness and make it more susceptible to life-threatening illness.
Fixing the problems associated with this wear-and-tear—or at least reducing their effects—could keep people healthy for longer, and so it’s no surprise that a large portion of medical research is focused on curing the ailments experienced with advanced age, like cancer, cardiovascular disease, Alzheimer’s or dementia. Eradicating these illnesses would prevent countless deaths and allow people to maintain a lifestyle more similar to that of their youth. But as Google/Calico CEO Larry Page claimed, curing cancer tomorrow would only add around 3 years to the average human lifespan. In other words: even without disease, time will eventually catch up with you.
Part of this is down to the program-related causes of aging. Namely, the human body has built-in processes that cause it to gradually deteriorate. The hypothalamus, a region of the brain designed to regulate temperature, hunger and mood—amongst other things—is programmed to change the body’s hormone levels as it gets older, encouraging the inflammation in various tissues that forms part of the aging process. Similarly, the DNA inside a cell is protected by telomeres; enzymes that coat the end of each chromosome to stop them from fraying, like the plastic caps on a shoelace. Each time a cell divides, the telomeres get shorter, which eventually leaves the chromosomes vulnerable to damage. Taken as a whole, these processes have caused some researchers to suggest that the human body has a hard-coded lifespan of around 115 years, and that no amount of medical expertise could help us overcome that limit.
The question, then, is what if you could somehow switch off those built-in processes? The answer may lie in epigenetics.
The Yamanaka Factors
Human DNA is comprised of over 20,000 genes, which decide everything from the way we look and act, to our health and general well-being. Rather than changing the genetic material in our cells, epigenetics modifies the way those genes are expressed, turning them active or dormant to produce a wide range of effects. The body utilises this technique all the time, and part of the aging process itself involves certain genes being gradually switched on or off, to the detriment of one’s health.
In 2006, Nobel-winning scientist Shinya Yamanaka discovered a combination of four genes that, when activated, caused a cell to rejuvenate itself. The process, which has been refined by further research, undoes those epigenetic changes caused by aging. Scientists hope that by learning to harness these four genes, they may eventually find a way to stop the aging process altogether.
Of course, the research is still in its infancy, and even if such a goal were achievable, there are still many hurdles left to overcome. One study found that keeping the genes active for too long turned cells cancerous, and even if the process can be perfected in a lab, there’s no guarantee it would yield any real practical application.
So when it comes to techniques that might radically extend our lifespans, we’ve still got a long way to go. And that’s without discussing whether an aging population really needs people to stick around for longer than they do already. But with advances in medicine over the coming decades, we can expect to see less diseases associated with our bodies’ wear-and-tear, and grow old with a little more spring in our step.
We may never make it past that built-in expiry date, but even then, 115 years is nothing to sniff at.