Ageing can feel remarkably sudden. One morning you awake to find new aches, or lapses in strength and memory that you could swear were not present just a few days prior. We do not literally age overnight, but as research is increasingly showing, we may not do so in a steady, linear path either.
Over the past decade a multitude of studies have suggested that ageing – at least for certain organs and bodily systems – may actually consist of long periods of stability, punctuated by inflection points or periods of rapid biological change. This shift in thinking has raised hopes for anti-ageing medicines. But it could also make us rethink our attitude to ageing in general, viewing it as a dynamic and varied journey – rather than simply a slow march of attrition and breakdown.
The latest study bolstering this view, published in Nature Communications, used a large number of brain scans to show that the structure and interconnectivity of the brain can be separated into five distinct eras, marked by turning points at nine, 32, 66 and 83. Of particular interest in this study is the identification of a very long “adolescent” phase from age nine to 32 in which brain connections appear to become stronger and more efficient – a period that extends well into what we traditionally consider a static “adulthood”.
Other recent studies looking at a variety of bodily structures have proposed a rapid period of ageing in many organs at around age 50; specific changes in metabolism and other systems around age 44 and 60; or that the skin as an organ goes through four distinct ageing phases, while the adult immune system ages in two phases.
These results are largely the fruits of the so-called “omics” revolution in research, with the generation of large datasets allowing the cheap and rapid measurement of an organ or body’s entire complement of proteins, DNA/RNA, or other molecules. (Of similar importance is an explosion in funding and interest for ageing research, likely a byproduct of our increasingly elderly society.)
At this stage many of the studies are underpowered – the widely covered Stanford study showing shifts at 44 and 60 had only 108 participants – and so specific claims they offer about a certain organ ageing at a certain time may not hold. But taken together they suggest that as far as our bodies are concerned, ageing is not a linear process.
If ageing is more acute than previously thought, it would seem ripe for simple interventions that could untip the tipping points, or leave checkpoints between eras unpassed. There is currently no shortage of tech moguls willing to try whatever scientific-ish treatments can be spun off from this preliminary research. Let them chance it. That sort of medical whack-a-mole is likely to be ineffective at best.
A bigger question is whether we even should prioritise interventions against ageing as such. The authors of the brain stage study were careful to not frame the transitions only in terms of decline, suggesting that each stage was simply a different phase in the journey of a human brain. This seems correct. As we head towards a more granular understanding of ageing, we may be able to better time and apply the anti-disease measures we already know about, from cancer tests to preventive medications. Prioritising wellness over raw longevity is the way to go – and if a longer life is the result, so be it.
