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Free · 3 minutes · No email

What’s your biological age?

Your body keeps its own calendar — and it rarely matches your birthday. A quick assessment across movement, heart, sleep, nutrition and more estimates how old your body really is — with a clear breakdown of what’s ageing you and what could change in a year. A few questions are optional — skip anything you don’t know.

No signup Answers stay in your browser Backed by research

How is biological age calculated?

The gold standard isn’t a questionnaire — it’s measurement. The markers that predict longevity best are VO2 Max (your cardiorespiratory engine), heart rate variability (nervous-system resilience) and body composition. Population reference tables turn each marker into an “age”: if your VO2 Max matches the average 32-year-old’s, your VO2 Max age is 32, whatever your passport says.

This quiz sits one step earlier, but it’s built on the same epidemiology. Each answer you give is mapped to its published effect on the risk of dying (a hazard ratio from large cohort studies); those effects combine, and the combined risk is converted into a biological age using the Gompertz mortality law — where risk roughly doubles every eight years of adult life. It draws on 32 factors you can report without a lab. Smoking, metabolic markers (blood sugar, blood pressure), fitness and how you rate your own health carry the most weight, which matches what the mortality research consistently finds. Don’t know your blood pressure or cholesterol? Pick “not sure” and it counts as neutral — no penalty. It’s transparent — the reveal shows exactly which factors moved your number, and a biological age for each system (cardio, metabolic, body, mobility, sleep and mind) — but it is a population-average estimate, not a measurement.

Biological age vs chronological age

Chronological age is arithmetic; biological age is biology. The gap between them is the interesting number: it tells you whether your body is aging faster or slower than the calendar, and it’s one of the few health numbers you can actually train. Research on what biological age means keeps landing on the same point — fitness markers dominate, and fitness markers respond to training.

From estimate to measurement

The quiz gives you a starting point — a one-time estimate from what you can report about yourself. The Sarvita app replaces it with a measured biological age from your real VO2 Max, HRV and body composition (via Apple Health), and it keeps that number live: it updates as you train, so it’s an ongoing score you can watch move, not a snapshot you take once. From there Sar, your AI coach, puts you on your Longevity Path — a weekly plan across five pillars (cardio, strength, nutrition, stability and sleep) that starts with the areas ageing you most, guiding you one pillar at a time and tracking the number as it drops. See the four pillars of longevity for the science behind the plan.

Biological age test — FAQ

What is biological age?
Chronological age counts birthdays; biological age reflects how old your body actually is, based on markers like cardiorespiratory fitness (VO2 Max), heart rate variability and body composition. Two 40-year-olds can be a decade apart biologically. Read more in what biological age actually means.
How is this biological age test calculated?
Each answer is mapped to its published effect on mortality risk — a hazard ratio from large cohort studies — and those risks combine and convert into a biological age using the Gompertz mortality law, the same maths epidemiologists use, where the risk of dying roughly doubles every eight years of adult age. So a combined risk twice the average reads as about eight years older; half the average, eight years younger. You answer 39 questions across nine areas (about you, body, movement, heart & vitals, sleep, nutrition, mind, environment, and medical & family history) feeding 32 factors, and the result shows not just one number but a biological age for each system — cardio, metabolic, body, mobility, sleep and mind — so you can see which part of you is ageing fastest. It’s a population-average estimate, not a diagnosis; the Sarvita app then measures the real thing from your VO2 Max, HRV and body composition via Apple Health.
How accurate is a biological age quiz?
A questionnaire can only estimate — it weighs the lifestyle factors research links to how fast people age, but it can’t see your actual VO2 Max, HRV or body composition, the markers that predict longevity best. That’s the honest ceiling of any self-report test. Treat the quiz as a starting point and a directional guide; a measured number is the real score.
Which factors move the number the most?
Smoking, diabetes and low cardiorespiratory fitness are among the heaviest — VO2 max is the strongest single predictor of longevity — alongside how you rate your own health and your usual walking pace, two of the strongest self-report signals in the research. Sleep, diet, blood pressure, mood and social connection each move it too. The reveal shows the full breakdown — every factor with a short, sourced explanation — plus a biological age for each system, so nothing is hidden. And most of them are trainable, which is why the result comes with a 12-month projection.
Can I enter my VO2 Max or body fat?
Yes — two of the quiz questions are optional inputs for exactly that. If you know your VO2 Max (from an Apple Watch, Garmin or lab test) or your body-fat percentage (from a smart scale or DEXA), enter them and they replace the self-reported estimates for a sharper number — or just skip them if you don’t. Either way it’s still an estimate based on population norms; the Sarvita app measures these continuously from Apple Health.
Can you actually reverse your biological age?
The markers behind it are trainable. VO2 Max responds to Zone 2 and interval work, body composition to strength training and nutrition, HRV to recovery and sleep. That’s why the projection screen shows a downward path — consistent training across the four pillars moves the number.
Is the test free? Do I need an account?
Yes — free, no email, no signup, and your answers are processed in your browser rather than stored on our servers. The Sarvita app, which measures your real biological age and coaches you to lower it, has a 7-day free trial.

The science behind your result

What biological age actually means

How one number captures how old your body really is — and how to lower it.

VO2 Max: the strongest predictor of longevity

Why cardiorespiratory fitness beats almost every other risk factor for survival.

The four pillars of longevity training

Zone 2, strength, VO2 Max and stability — the framework that moves the number.

HRV and longevity

What heart rate variability measures, and what your nervous system has to do with aging.

This quiz produces an educational estimate, not a medical assessment or diagnosis. For adults 18+. Your answers are processed in your browser and are not stored on our servers — see the privacy policy.