The third hallmark of ageing revolves around epigenetic "switches" that control which genes are active - mechanisms that can be influenced by lifestyle choices and environmental factors throughout life. These reversible changes represent one of the most actionable aspects of biological ageing, offering unprecedented opportunities to potentially slow, or even partially reverse the ageing process through evidence-based interventions.

Today we continue our Hallmarks of Ageing series with the second hallmark, telomere shortening, a gradual process wherein the protective ends of chromosomes diminish with each cell division.

Genomic instability, caused by DNA damage, is a primary hallmark of ageing. The evidence is compelling: while people with DNA repair disorders show accelerated aging, centenarians often have genetic variants that enhance DNA repair, suggesting that protecting our genome could be key to promoting a healthy lifespan.

Meet the 12 'Hallmarks of Ageing' - the cellular processes that drive how we age. From DNA damage to cellular 'zombies', we're making the science accessible.