Chronological vs Biological Age
Chronological age is simply time since birth. Biological age attempts to measure how your body is actually ageing at a cellular level, independent of your birth year. The gap between the two is where longevity research gets interesting.
How It's Measured
The most validated measure is the epigenetic clock — particularly Horvath's clock and Levine's PhenoAge — which use DNA methylation patterns at specific CpG sites to estimate biological age. These clocks can now be measured from a simple blood or saliva sample via commercial tests.
Other proxies include VO2 max (arguably the strongest single predictor of all-cause mortality), grip strength, and inflammatory markers like CRP and IL-6.
What Changes Your Biological Age
The five interventions with the strongest evidence for improving biological age metrics:
- Aerobic exercise — VO2 max improvements are measurable and reproducible
- Caloric restriction or time-restricted eating
- Stress reduction (chronic stress ages the epigenome measurably)
- Quality sleep — methylation patterns are disrupted by chronic sleep deprivation
- Resistance training — preserves muscle mass and insulin sensitivity with age
Take our Longevity Questionnaire to see how your current lifestyle compares against the evidence-based pillars of healthy ageing.