How to read the numbers: Fact = a finding from research or biology · Term = a key term or marker worth knowing
Max. gap between bio and chrono age
In studies, some people's biological age differs from their chronological age by more than a decade, in either direction. This shows that the pace of ageing is not fixed – sleep, exercise, diet and stress measurably influence it.
The most accurate biomarker
Epigenetic clocks estimate biological age from DNA methylation and are among the most studied biomarkers of ageing; however, different tests and labs give different numbers. If you measure it, repeat the same test at intervals and follow the trend.
The rest is lifestyle
Genes have only a minority influence on lifespan – precise estimates vary between studies, but lifestyle and environment make up most of it. The good news: regular exercise, quality sleep, a plant-rich diet and not smoking are in your hands.
Biological age reflects the functional state of your organs, cells and molecular pathways — not the time since you were born. Two 50-year-olds can have biological ages of 40 and 65. Longitudinal research (the Dunedin Study) has recorded gaps of 13 years in biological age between people of the same chronological age.
In 2013, Steve Horvath (UCLA) developed a mathematical model that predicts biological age from DNA methylation at 353 CpG sites in the genome. Accuracy: ±3–4 years. Today there are 2.0 versions (PhenoAge, GrimAge) that also predict lifespan and the risk of specific diseases.
What biological age is
At the cellular level: telomere length, DNA methylation, accumulation of senescent cells, mitochondrial function. At the systemic level: cardiovascular fitness (VO2max), muscle strength (grip strength), cognitive speed, microbiome diversity, inflammatory markers (CRP, IL-6). According to some longevity researchers, VO2max is the best single predictor of lifespan.
How biological age is measured
Epigenetic tests (TruAge, MyDNAge, Elysium Index) — the gold standard, 300–600 EUR. Telomere testing (Life Length) — a less stable marker. Blood biomarkers: a PhenoAge calculator based on routine lab values (glucose, albumin, CRP, lymphocytes, MCV, alkaline phosphatase). A VO2max test in a sports laboratory. A grip strength dynamometer — grip strength correlates with mortality more strongly than blood pressure does.
What accelerates it
Chronic stress, smoking (10 years of biological ageing), obesity, a sedentary lifestyle, chronic inflammation ("inflammaging"), lack of sleep, social isolation, low dietary variety, alcohol.
How to slow it down — the evidence
Caloric restriction (without malnutrition) — the most robust evidence from animal models; in humans, the CALERIE study showed a 2–3-year improvement in biological age over 2 years. Aerobic fitness (VO2max) — the most powerful modulator. Strength training preserves muscle mass and mitochondrial biogenesis. 7–9 hours of sleep. A Mediterranean diet with a high polyphenol load. Rapalogs (rapamycin, berberine) — mTOR inhibition. NMN/NR — NAD+ precursors for mitochondrial function.
