Healthspan: what science really knows about living longer in good health

Worldwide, the World Health Organization puts life expectancy at 71.4 years in 2021 and healthy life expectancy at 61.9 years: on average, almost ten years are lived in poorer health.

Europe measures the same gap with “healthy life years”, based on whether people report being limited in their usual activities by a long-standing health problem. According to Eurostat, in 2023 a woman in the European Union could expect to live 84.0 years at birth, 63.3 of them in good health; a man, 78.7 years, 62.8 of them in good health.

Two lessons stand out. The gap is large: more than twenty years for women, about sixteen for men. And women live longer than men, but barely more of those years in good health: the gender gap is much smaller for healthy life years than for life expectancy. Life expectancy is the headline figure; healthspan is the one that describes daily life.

A 2018 study published in Circulation followed more than 120,000 US health professionals for up to 34 years and defined five low-risk lifestyle factors:

• never smoking;
• a body mass index between 18.5 and 24.9;
• at least 30 minutes a day of moderate to vigorous physical activity;
• moderate alcohol intake;
• a high-quality diet (the top 40% of the study’s diet scores).

Projected onto the US population, life expectancy at age 50 was estimated at 43.1 years for women with all five factors, against 29.0 years for women with none: a 14-year difference. For men, it was 37.6 years against 25.5, a 12.2-year difference.

These figures call for careful reading. This is an observational study: it shows a strong, consistent association, not a guaranteed gain for someone who changes their habits. It measures life expectancy, not healthy years directly. And the alcohol criterion is the study’s, not a recommendation: the World Health Organization states that no level of alcohol consumption is safe for health. Supplements, as we will see, offer nothing close to this level of evidence.

What about genetics?

Longevity is often said to “run in families”. Classic estimates of its heritability are already modest, around 15 to 30%. A 2018 study in Genetics, based on family trees covering hundreds of millions of people, concludes that even these are inflated: much of the resemblance between relatives also shows up between in-laws, who share no genes, because partners tend to choose each other on factors that influence lifespan. Once this is accounted for, the heritability of lifespan comes out well below 10% for people born in the 1800s and early 1900s.

Working on your healthspan means knowing where you stand. Three markers come up often; none of them is a diagnosis, and each one helps estimate a risk.

Biological age

The idea is that two people of the same age in years do not age at the same pace. One of the measures studied, “Phenotypic Age”, combines chronological age with nine markers from routine blood tests. In a large US population, it remained associated with mortality after accounting for chronological age, including in people who appeared healthy. Its authors note that it still needs to be evaluated in other cohorts. What biological age really measures, and what it does not, deserves the same caution as any single result: for the markers it is built on, our guide on how to read blood test results is the right place to start.

Cardiorespiratory fitness

In a 2016 scientific statement, the American Heart Association points out that low cardiorespiratory fitness is associated with a high risk of cardiovascular disease, all-cause mortality and mortality from various cancers, and that it may be a stronger predictor of mortality than established risk factors such as smoking, high blood pressure or type 2 diabetes. It makes the case for fitness as a “clinical vital sign”. Fitness is often expressed as VO2 max, the maximum rate of oxygen uptake. If your watch shows an estimate, keep in mind what health wearables measure well, and less well.

A prevention check-up

The simplest marker is also the most underrated: reviewing your risk factors with a professional, at the ages when it is recommended. A well-prepared preventive health check-up covers exactly the levers from the previous section: smoking, physical activity, diet, weight and alcohol.

Ranked by strength of evidence, longevity levers look nothing alike.

Dietary supplements

In 2022, the US Preventive Services Task Force reviewed vitamins and minerals taken to prevent cardiovascular disease and cancer. Its conclusions: the evidence is insufficient to assess multivitamins and most single or paired supplements, and it recommends against beta-carotene and vitamin E for this purpose. Vitamin E showed no net benefit, and beta-carotene was linked to a higher risk of lung cancer in people who smoke or were exposed to asbestos at work.

As for products sold to make you younger, the National Institute on Aging notes that a wide range of supplements claim, without scientific evidence, that they can “turn back the years”.

Why research is moving fast without concluding yet

The biology of aging is advancing quickly. A landmark review published in Cell in 2023 describes twelve hallmarks of aging, from genomic instability to chronic inflammation and cellular senescence. To make the list, a mechanism must worsen with age, speed up aging when experimentally accentuated, and offer an opportunity to slow aging through an intervention.

That is exactly what fuels the promises: an identified mechanism quickly becomes a product. But acting on a mechanism in the lab is not the same as showing that people live longer in good health. The same goes for medicines taken off-label in the hope of slowing aging: every medicine has side effects, and the decision belongs to a doctor, not to a protocol found online. The same sorting applies in a longevity medicine consultation: for every test or prescription offered, ask what evidence it rests on.

The best-supported levers are also the least spectacular. They require no product and no protocol:

• move regularly: the WHO recommends at least 150 minutes of moderate-intensity physical activity a week for adults;
• stop smoking, or never start;
• look after your diet and keep alcohol low;
• review your risk factors with your doctor, and come back to them over the years.

Healthspan plays out over time: a single measurement says little, its trend says more. Following your data over time to estimate a risk is the principle behind predictive health. The same logic applies at work, where healthy aging at work is also something employers can support.

With MyTwin for patients, your reports, lab results and treatments come together in a health digital twin, to help you better understand your body and its early signals. Decisions are made with your doctor.