How old Is your body really? The science of Biological Age.(by Dr Krish Rawal, Infinity Group Medical Director)

We all have a chronological age — the number of years since we were born—but this may not tell us how old our bodies really are. Two people of the same age can have very different levels of cardiovascular fitness, metabolic health, cognitive function and susceptibility to disease. This has led to growing interest in biological age; an attempt to measure how quickly an individual’s body is ageing compared with others of the same chronological age. Ageing is now understood as a complex interaction of processes including genetic instability, mitochondrial dysfunction, cellular aging and breakdown and chronic inflammation. The influential “hallmarks of ageing” framework describes twelve interconnected biological processes that contribute to ageing and age-related disease.

One of the most promising ways of measuring biological age involves epigenetics, particularly patterns of DNA methylation. Researchers have developed mathematical “epigenetic clocks” that analyse thousands of methylation sites to estimate biological age. Newer generations, including PhenoAge, GrimAge and DunedinPACE, attempt to go beyond simply predicting chronological age and instead measure characteristics associated with disease, mortality and the rate of ageing.

Other emerging approaches analyse blood proteins, metabolites, imaging and multiple biological measurements simultaneously. Recent research is increasingly demonstrating associations between accelerated biological ageing and important health outcomes, including cardiovascular disease, mortality, cognitive decline and dementia. A 2026 prospective study of more than 6,000 older women, for example, found that accelerated ageing measured by an epigenetic clock was associated with an increased subsequent risk of mild cognitive impairment or probable dementia.

The really exciting question is whether biological ageing can be slowed or reversed. Exercise, maintaining muscle mass, avoiding smoking, healthy nutrition, good sleep, weight management and control of blood pressure and metabolic risk factors are all associated with healthier ageing. However, we should be cautious about interpreting a change in a biological-age test as proof that someone has actually become biologically younger. There is currently no universally accepted definition or gold-standard test for biological age, and different clocks can produce different results. A 2025 review highlighted important uncertainties regarding the clinical validation and interpretation of these tests. In other words, an ageing clock is a biomarker, not a direct measurement of the ageing process itself.

Nevertheless, this rapidly developing field could eventually change preventive medicine. Rather than simply recording someone’s chronological age, future healthcare may combine genetics, blood biomarkers, physical fitness, body composition, imaging and biological-age measurements to identify which aspects of an individual’s health are ageing faster than expected. The aim would not be to make a laboratory number look younger, but to identify potentially modifiable risks early enough to intervene. We are moving towards an intriguing new concept: ageing not simply as an inevitable number on a birth certificate, but as a biological trajectory that may be influenced by how we live and, potentially, by future medical interventions. Perhaps the ultimate goal of longevity medicine is not simply to add years to life, but to add healthy years to life—extending healthspan rather than merely lifespan.

So next time you are in the gym, pushing hard and your muscles are telling you to stop, remember it is definitely worth it!!