Biological Age: How Old Is Your Body Really?

Your body has its own calendar, and it doesn’t always match what’s on your ID. Biological age, measured through biomarkers, reveals how we truly age and opens a horizon where science and prevention come together to add healthy years of life.

Living 70 years doesn’t necessarily mean your body is “70 years old” in terms of health and functioning. Two people with the same chronological age can be in very different stages of their biological aging: one may have the vitality and physical capacity of someone 55, while another may show frailties typical of someone 80. The key lies in a concept that is transforming science and public health: biological age.
What is biological age?
Chronological age is the time that has passed since your birth. Biological age, on the other hand, measures the real state of your body: how your cells, tissues, and systems are functioning.
It is calculated from biomarkers: measurable parameters that reflect key processes of aging, such as telomere length, levels of inflammation, the capacity of the immune system, or the balance of oxidative stress.
In the United States, the National Institute on Aging has been funding research for more than a decade to identify a reliable “biological clock.” In Europe, projects such as MARK-AGE have studied thousands of people to connect biomarkers with health and longevity.
Why it matters: beyond scientific curiosity
Knowing your biological age is not just a lab game. It has profound implications:
Evaluating the impact of habits and treatments: it helps measure whether a diet, an exercise program, or a medication is slowing down—or accelerating—you’re aging.
Designing public policies: it could redefine criteria for access to health, prevention, or retirement programs.
In Japan, some municipalities already incorporate indicators of functional capacity (closer to biological age than chronological) to prioritize prevention services.
Real-life examples: from science to everyday life
In New Zealand, a long-term study of more than 1,000 people since birth showed that those who age biologically more slowly maintain better memory, cardiovascular health, and physical capacity in midlife.
In Spain, Dr. Mónica de la Fuente and CENIE are working on measuring biological age through immune and oxidative stress biomarkers, with the aim of guiding community prevention policies.
In the United States, private clinics offer “epigenetic clock” analyses to estimate biological age, although the scientific community stresses that there is still no consensus on its clinical use.
But research hasn’t stopped there: today, new frontiers are emerging that take biological age from the lab into everyday prevention.
New frontiers: from the lab to everyday prevention
Research in this field is moving toward very practical applications.
In some European hospitals, pilot programs are already being tested that combine biological age analysis with personalized health plans: nutritional recommendations, exercise routines, and sleep guidelines based on the body’s real condition, not just chronological age. Even large tech companies are developing at-home devices that, using small saliva samples or dried blood spots, could provide periodic estimates of biological aging.
The interest is not only medical: cities like Copenhagen or Helsinki are exploring ways to incorporate collective biological age indicators into their urban plans, aiming to design healthier neighborhoods and measure whether housing, transportation, or green space policies affect the pace of population aging.
It’s a conceptual leap: longevity stops being just an individual fact and becomes a community well-being goal.
Ethical and social implications
Biological age raises sensitive debates:
Labor rights and retirement: would it be fair to delay or advance retirement age based on your biological age?
Insurance and privacy: could insurers use this information to adjust policies?
Equity: social and environmental inequalities influence biological age; ignoring this could widen existing gaps.
In Canada, a bioethics committee has warned that any use of biological age must be accompanied by legal and ethical safeguards to prevent discrimination.
Toward a new pact with our own time
Advances in measuring biological age bring us closer to more personalized health and smarter policies but also demand a new culture of care: accepting that our years of life are not only counted, but cultivated.

As a longevity society, we have the opportunity to use this information to gain healthy years of life, not to label or exclude.
Each of us, ultimately, has the ability to negotiate with our own biological time.

If you knew your biological age…, what would you change today in the way you live?