Calculating life expectancy: what the models do and do not include

Calculating your life expectancy means running a statistical model that compares your age, sex and a handful of lifestyle factors against mortality data from large populations. The result is an average of people like you, not a prediction about you.

That distinction is the whole point.

Most online calculators ask about smoking, alcohol, BMI and activity. They almost never ask about the factor with the strongest measured association with mortality, and one you can actually change: your fitness.

How is life expectancy calculated?

The basis is a life table. Statisticians count how many people die per year in each age group, then work back to how many years someone your age has left on average.

The Dutch public health institute RIVM publishes those figures for the Netherlands, split by age and sex.

An online calculator adds a correction layer. If you smoke, it subtracts years based on how much earlier smokers die on average in the data. If you exercise a lot, it adds some back.

What you get is an average with a few sliders attached. Useful for direction, not for putting a date in your calendar.

Which factors are usually included?

The input fields look remarkably similar across calculators, because they all draw on the same kind of cohort research. What stands out is how much of it you cannot change.

The bottom two rows are exactly the rows you have influence over. They are missing because a web form cannot run an exercise test or draw blood.

Which factor predicts most strongly?

Based on available cohort research, that is your cardiorespiratory fitness, or VO2max. A 2024 overview of meta-analyses pooled almost 21 million observations from 199 cohorts and described fitness as a strong and consistent predictor of morbidity and mortality.

That is an unusually large body of data behind one conclusion.

An earlier analysis of more than 122,000 people who underwent treadmill testing found the association continued into the highest fitness groups, with no clear ceiling. A meta-analysis in JAMA had already described each step up in fitness tracking with lower risk.

An important caveat: this is association from observational research, not proof that training buys you years. People with a high VO2max differ from people with a low one in other ways too.

Even so, it is the one row in the table above you can move yourself and that keeps recurring this consistently. How to build it sits in zone 2 training, and what counts as a good value by age is in what is a good VO2max.

Can you calculate your biological age instead?

That is the fairer question, because it is about now rather than about 2070. Your biological age tries to describe how your body is doing compared with peers.

Our biological age calculator works that through from your own data.

What such an estimate is worth depends on what you feed it. Base it on questionnaires and you get a questionnaire answer. Add measured values and it becomes concrete, which is exactly what measuring biological age sets out.

Which blood values track with mortality risk?

A few values recur in cohort research when they stay elevated over long periods. They predict nothing about an individual, but they do give direction to what you can follow.

Think of hs-CRP as a measure of low-grade inflammation, ApoB for the number of atherogenic particles, and HbA1c for your blood sugar across months.

We work out the inflammation side in chronic low-grade inflammation.

These values are not a goal in themselves. They are the feedback on everything else you do.

Where do you start?

Fill in a calculator once as a baseline, then let it go. Next, pick one row from the table you can genuinely move, and measure that every quarter.

For most people that is their fitness.

If you want the metabolic side alongside it, our insulin resistance test gives you glucose and insulin with an assessment by a BIG-registered doctor. The broader approach sits in the guide to healthy ageing as an athlete.

References

1. Lang JJ, Prince SA, Merucci K, et al. Cardiorespiratory fitness is a strong and consistent predictor of morbidity and mortality among adults: an overview of meta-analyses representing over 20.9 million observations from 199 unique cohort studies. British Journal of Sports Medicine. 2024. PMID 38599681.
2. Mandsager K, Harb S, Cremer P, et al. Association of cardiorespiratory fitness with long-term mortality among adults undergoing exercise treadmill testing. JAMA Network Open. 2018. PMID 30646252.
3. Kodama S, Saito K, Tanaka S, et al. Cardiorespiratory fitness as a quantitative predictor of all-cause mortality and cardiovascular events in healthy men and women: a meta-analysis. JAMA. 2009. PMID 19454641.
4. Laukkanen JA, Isiozor NM, Kunutsor SK. Objectively assessed cardiorespiratory fitness and all-cause mortality risk: an updated meta-analysis of 37 cohort studies involving 2,258,029 participants. Mayo Clinic Proceedings. 2022. PMID 35562197.
5. RIVM. Life expectancy, figures and context. Accessed 2026.

Disclaimer

Every blood test result includes a professional assessment by a BIG-registered doctor. This article provides general information and is not a substitute for medical advice. Discuss your results with your doctor before making treatment decisions.