# Biological Age > Updated: 2026-05-14 · Source: https://dorsi.ai/pillars/biological-age Your biological age — how old your body actually behaves — can diverge from your chronological age by a decade in either direction. This pillar covers the markers that move it and the interventions that move them. Chronological age is a clock; biological age is a status report. Two 45-year-olds can look identical on paper and yet have cardiovascular fitness, muscle mass, glucose regulation, and inflammatory markers that put one in their thirties and the other in their late fifties. That gap — sometimes called your "fitness age" or "pace of aging" — is the actual lever you have control over. The number on your driver's license is fixed; the rate at which your body is aging is not. This pillar walks through the measurable inputs that shape biological age: cardiorespiratory fitness (VO2 max is the single strongest predictor of all-cause mortality), muscle mass and strength, glucose control, sleep quality, stress regulation, and a handful of bloodwork markers. We translate each marker into what it actually predicts about healthspan and longevity, what range is healthy for your decade of life, and the specific interventions — most of them stunningly simple — that move it. Dorsi's health coach is built around the metrics that matter most for biological age, with resistance training as the first intervention because the evidence base for its effect on healthspan in your 40s, 50s, and beyond is overwhelming. The articles below give you the underlying science; Dorsi turns it into a weekly routine you'll actually do. ## FAQ ### What is biological age? Biological age estimates how old your body behaves based on health markers — fitness, recovery, and metabolic signals — rather than years since birth. Two people the same chronological age can have very different biological ages. ### Can I lower my biological age? You can improve the markers that drive it: cardiorespiratory fitness (VO2 max), strength, sleep, and recovery. Consistent training and better sleep move these over months, not days. ### How is biological age calculated? Calculators combine markers like VO2 max, resting heart rate, and body composition into an estimate. They're directional, not diagnostic — most useful for tracking your own trend over time.