Biological age: how to measure and improve it

Your biological age indicates how your cells have truly aged, and it may be higher or lower than the age shown on your identity document. It is measured using biomarkers such as DNA methylation and can be improved through specific habits and medical monitoring. Two people aged 50 may have bodies that function as if they were 42 or 58. That difference is the one worth knowing and working on.

This concept has moved from the laboratory to the clinic because ageing has become measurable. Tests now exist that estimate how much wear your body has accumulated, and programmes aimed at rejuvenating those markers. Below you will find what separates biological age from chronological age, which tests reveal it, and what you can do with the result.

Chronological Age vs Biological Age

Chronological age is the time elapsed since your birth; biological age estimates the actual deterioration of your tissues. The first advances at the same rate for everyone. The second depends on genetics, environment and, above all, on daily choices. That is why two people born on the same day can age at different rates.

Interest in this distinction is growing alongside the population. The World Health Organization estimates that the number of people aged 60 or over will double to reach 2.1 billion by 2050, and that the over-80 age group will triple to 426 million (World Health Organization, October 2024). Ageing well, and not merely for longer, has become a public health priority.

Why does this difference matter so much? Because chronological age cannot be changed, but biological age responds to your habits. Knowing it gives you a measurable starting point and a way to check whether what you are doing is working.

Biomarkers That Indicate How Your Body Is Ageing

Biomarkers are measurable signals of cellular ageing, and epigenetic clocks stand out for their precision. Research funded by the United States National Institutes of Health concluded that the GrimAge clock predicts mortality with greater risk than telomere length (Aging Cell, 2025). This finding has reshaped which markers are worth measuring.

It is worth knowing the three main families:

• Epigenetic clocks: these analyse DNA methylation patterns — that is, which genes are switched on or silenced. Models such as GrimAge or DunedinPACE estimate biological age and the pace of ageing.
• Telomeres: these are the protective caps at the ends of chromosomes, which shorten with each cell division. Their length provides useful information, although today they are considered less predictive than second-generation clocks.
• Inflammation and metabolic markers: C-reactive protein, glucose, lipid profile and other parameters reflect accumulated wear and chronic low-grade inflammation.

No single marker tells the whole story. A thorough analysis combines several of them to provide a reliable picture. In clinical practice, this integrated view is the foundation of longevity medicine, which studies ageing as a modifiable process.

Habits that accelerate or slow cellular ageing

Daily habits can shift your biological age by years, and diet tops the list. In a clinical trial, a fasting-mimicking diet reduced participants' biological age by an average of 2.5 years (USC Leonard Davis School of Gerontology, February 2024). The body responds to what you do in measurable ways.

Some factors accelerate the cellular clock. Smoking, excess sugar, a sedentary lifestyle, insufficient sleep and chronic stress all promote inflammation and DNA damage. In a sunny region like the Costa del Sol, unprotected sun exposure adds a further driver of accelerated skin ageing.

Other habits slow or even partially reverse the wear. Regular physical activity, a diet rich in vegetables, adequate rest and stress management all improve these markers. Consistency matters more than intensity: small changes sustained over months outperform isolated bursts of effort.

Tests available to determine your biological age

Today you can measure your biological age with accessible laboratory tests, and DNA methylation tests are the most well-established. A blood or saliva sample makes it possible to estimate your epigenetic age using the clocks mentioned above. The result is expressed in years and compared with your chronological age.

The range of options includes:

• Epigenetic tests: these measure DNA methylation and return an estimated biological age, as well as the pace of ageing in models such as DunedinPACE.
• Telomere panels: these calculate the average length of your telomeres — a complementary data point, though less precise on its own.
• Functional blood panels: inflammation, glucose metabolism, hormonal profile and vitamins, which provide context on your overall health status.

An important note: the reliability of these tests varies greatly depending on the provider, and a 2026 scientific review raised concerns about their rigour when offered outside a medical context. Interpreting results with a professional avoids jumping to conclusions. At Clínica Valorian, Dr. Florian A. Vallecillo Cabrera integrates these measurements into a comprehensive clinical assessment — not as an isolated figure.

How to design a plan to rejuvenate your markers

An effective plan starts with an initial measurement and turns it into concrete, reviewable actions. The evidence supports this approach: an 8-week diet and lifestyle intervention was associated with a 3.23-year reduction in epigenetic age compared to the control group (Aging journal, pilot clinical trial). Measurable change is possible within short timeframes.

A well-structured plan typically follows these steps:

1. Measure your starting point: a biomarker blood panel and, where appropriate, an epigenetic test establish the baseline.
2. Prioritise the highest-impact factors: diet, exercise, sleep and stress management tend to deliver the greatest results.
3. Personalise the interventions: the approach must be tailored to your medical history, test results and goals.
4. Reassess over time: repeating the tests after several months shows whether your markers are improving and allows you to adjust course.

Skin health is part of this picture, as cutaneous ageing reflects internal processes. This is why a longevity plan pairs well with aesthetic medicine in Marbella when the goal also includes outward appearance.

If you want to know your biological age and translate it into a realistic plan, the next step is simple: book a medical assessment that combines the right tests with follow-up over time. A number only changes anything when it becomes sustained decisions.