Legitimate science investigating ways to slow or reverse the ageing process is thankfully getting much more attention than it once did. Unfortunately, there are still a lot of misconceptions surrounding this research, as well as the nature of the ageing process itself. What follows are some of the biggest myths about ageing and its reversal.
You often hear people say things like ‘40 would have been considered old by ancient Roman standards’ or ‘living to age 100 would have been unthinkable for most of history’. This is probably not true – provided they were not killed by violence or infectious disease, our ancestors would have had a decent shot at living what would be considered long lives even by today’s standards. Based on the limited available historical data, it seems as though those who survived until adulthood and avoided war could expect to live to age 60 or 70. The Roman author and naturalist Pliny also wrote of multiple people living past age 100.
Likewise, our ancestors would not necessarily have considered 40 year-olds to be ‘old’ simply because reaching this age was less likely than it is today – the oldest humans in society would not have been that much younger than they are today.
While human life expectancy has increased dramatically over the past 100 years, there’s not much evidence that we are ageing any more slowly – we’re just more likely to survive both infectious and age-related diseases. In fact, most of the gains in life expectancy over the last century have nothing to do with age-related diseases and everything to do with vaccines, antibiotics, and reduced infant mortality.
We have certainly become better at treating age related diseases. People with type II diabetes, once a death sentence, can now live mostly normal lives. People with cancer can hope to be cured or at least to survive for many more years after their diagnosis. However, our ability to keep people with age-related diseases alive does not mean that anyone is ageing more slowly. If they were, we might expect people to develop age-related diseases later in life, and we would expect to see people surviving to unprecedented ages in each new generation. Instead, we simply see that an increasing proportion of the population is living with incurable and debilitating disease.
Age related diseases are not currently reversible, but that doesn’t mean it’s too late to adopt healthy lifestyle practices. Research repeatedly shows that no matter how old you are, practices like regular exercise or improving your diet have a significant effect on health and longevity. Research even suggests that you can quit smoking after decades and still recover most of the life expectancy you would otherwise have lost.
This was once thought to be true, but it turns out to be wrong. While neurogenesis (formation of new neurons) and brain plasticity (the brain’s ability to ‘rewire’ itself) do decrease with increasing age, neither declines to the extent previously thought. It turns out that even 80 year-old brains continue to grow new brain cells. Older people do struggle to acquire new skills, but a large part of this is probably due to loss of confidence or the assumption that new information won’t be retained (and so there’s no point in trying).
It’s normal to want simple solutions to complicated problems, and many imagine ageing as a single process for which there could be a golden bullet. The reality is that we know of at least 4-5 primary drivers of ageing that would all need to be reversed in order for ageing to be prevented entirely. There are, in total, at least 12 drivers of ageing that could provide therapeutic targets.
When people list the benefits that come with ageing, most of the examples they give (such as greater wisdom or having grandchildren) are actually the result of time spent alive. This is obviously not the same thing as being biologically old, though it’s easy to see why these two things are conflated given the inevitability of ageing throughout all of human history. Unfortunately, there are very few benefits to biological ageing, and they are far outweighed by the downsides.
As for the argument that a limited lifespan gives our lives meaning, might I suggest culling all humans at age 40? Think how much more meaningful our lives would be!
A treatment that truly slows down the ageing process is likely to make people live longer, and may one day even allow humans to live forever, barring fatal accidents. However, the main goal of anti-ageing research today is not to extend human lifespan, but healthspan – the duration of life spent free of age related disease and disability. Suppose the average age of onset of a disease is 65. If we can make the body of a 65 year-old operate like that of a 60 year-old, then we would not expect them to develop that disease until they were about 70. That’s 5 extra disease-free years – a huge success regardless of how long the individual ends up living.
The ultimate success would be something called negligible senescence. Negligible senescence is where an organism shows little to no signs of ageing right up until they die. We know that negligible senescence is possible because some mammals (such as the naked mole-rat) experience it. While negligible senescence is a lofty goal, it is much more attainable than immortality.
This is kind of like saying we should focus on curing lung cancer and emphysema before we think about banning cigarettes – both are important but only one provides a long-term solution to the problem, and is also significantly more efficient. Most of the World’s most deadly and debilitating diseases like cancer, heart disease and dementia are all caused by ageing. If we could delay the ageing process by even one year, we would also delay the onset of all of these diseases by one year with just a single intervention. The impact of this on human health and wellbeing has the potential to far surpass any intervention targeted at a specific disease.
We obviously should be searching for cures for cancer and other age-related diseases, but the idea that targeting the ageing process detracts from these efforts doesn’t make a lot of sense. We are trying to target ageing so that we don’t need to treat cancer, heart disease and diabetes as often.
Currently, many interventions proposed to slow ageing are expensive. However, once we understand how to reliably slow or reverse ageing, it is likely that any such treatment will be delivered using genetic techniques like gene therapy. Given the massive rollout of gene therapy and mRNA-based covid vaccines, it’s hard to see why such a treatment couldn’t be made affordable.
Even if an age-delaying therapy does end up being expensive, it will still be in the interests of most governments to provide it for free. Treating age-related disease is very expensive, and slowing the rate of ageing even slightly would have massive economic benefits for any country.
Current predictions suggest that the global population will peak around the mid 2080s, after which it will begin to decline. Whether the population goes up or down in a given year depends on how many people are born vs how many people die. If treatments that slow or reverse ageing result in people living longer, then this may indeed cause the population to grow faster for a time. However, the global fertility rate is declining and will drop below replacement level (the fertility needed to replace the previous generation) somewhere between 2050 and 2080. Once this happens, population decline is inevitable long-term unless human lifespan is vastly extended.
It’s also questionable whether overpopulation would occur, even if the population continues to increase. There’s really no reason to think the Earth can’t support many more people than it does now. The population more than doubled during the 20th century without any global catastrophes. We should be more concerned about the age distribution of our population than its size. In 2020, about 9% of the global population were over the age of 65, but by 2080 that number will be over 20%. This means that the number of people requiring health and social care will increase relative to the number of people available to provide it. The best way to solve this problem is to make older people young again.