Longevity means an unusually long individual life, and it is not the same as life expectancy, which is a population average. In the UK, life expectancy at birth is 79.1 years for men and 83.0 for women, while healthy life expectancy in England stops around 62. That gap of roughly two decades is what longevity research is trying to close.
Search for longevity in Britain and you get two kinds of page. Dictionaries, which define the word and stop. And lifestyle lists, which tell you to floss, sleep and make friends without ever saying how many years any of it is worth. Both are correct. Neither helps you decide what to do on a Tuesday.
This article takes the third route. Every claim below carries the number attached to it, from the study that produced it, in the units that matter: years of life, or percentage change in mortality risk. Where the honest answer is that nobody knows, it says so.
What does longevity actually mean?
Four words get used interchangeably and mean four different things. Getting them apart is not pedantry, because most of the confusion in this field comes from mixing them up.
Lifespan is how long one person lives, birth to death. Life expectancy is a statistical average across a population, and it moves with infant mortality, road deaths and pandemics as much as with ageing. Longevity refers to unusually long life, the far right tail of the distribution. Healthspan is the portion of life spent free of serious disease and disability.
A fifth term, biological age, is newer and shakier. It describes estimates of how old your tissues appear from markers such as DNA methylation patterns. These clocks correlate with mortality risk across large groups. On an individual, they are not yet accurate enough to guide a decision, and different clocks routinely disagree about the same person by several years.
The British number nobody quotes: years lived against years lived well
Period life expectancy at birth in the UK, for 2022 to 2024, was 79.1 years for males and 83.0 years for females. Female life expectancy has returned to its 2017 to 2019 level. Male life expectancy is still slightly below it, by ten weeks in England.
Now the other measure. Healthy life expectancy at birth in England, for 2020 to 2022, was 62.4 years for males and 62.7 years for females. Same country, same people. Roughly seventeen years for men and twenty for women lived with a significant health condition or disability.
ENGLAND AND THE UK: YEARS LIVED, YEARS LIVED IN GOOD HEALTH
That is the real target. Adding years to the end of a life spent managing multiple long-term conditions is not what most people mean when they say they want to live longer. Compressing the unhealthy stretch is. Almost every serious longevity researcher now frames the goal this way, and it changes which interventions are worth your attention.
How much of longevity is genetics?
Far less than the folklore suggests. Estimates of the heritability of human lifespan have long sat around 15 to 30 percent, which is where the idea that long life runs in families comes from. Then a team analysed pedigree data from hundreds of millions of historical people in Ancestry public trees, and found something awkward.
Most of the correlation between genetic relatives was also present between in-law relatives, who share no genes at all. People pair up with partners of similar background, income, education and habits, and that assortative mating inflates the apparent genetic signal. Corrected for it, the true heritability of human longevity for cohorts born across the 1800s and early 1900s came out well below 10 percent.
Read that as good news rather than as a licence. It means the family history you cannot change explains a small share of the outcome, and the environment and behaviour you can change explain most of the rest. It does not mean genes are irrelevant. Among people who reach 100, the genetic contribution appears larger, which is a different question about a different tail of the distribution.
WHAT SETS HOW LONG YOU LIVE
healthy life
Heritability, under 10%
The share attributable to inherited genetics once assortative mating is removed from the pedigree estimates.
Diet
Modelled at up to 10.7 years for women and 13.0 for men when changed from a typical Western pattern at age 20.
Physical activity
A 31 percent lower mortality risk at one to two times the recommended weekly minimum, in 661 137 adults.
Social connection
Social isolation raises mortality risk by 29 percent, loneliness by 26 percent, living alone by 32 percent.
Smoking and alcohol
The two behaviours with the largest and best established effect on premature mortality in the UK population.
Can human lifespan be pushed much further?
Over the twentieth century, life expectancy at birth rose by roughly 30 years in high-income nations. That came from public health and medicine, not from slowing ageing: clean water, vaccination, antibiotics, then treatment for heart disease. It was a one-off harvest of early deaths, and it is largely done.
A 2024 analysis in Nature Aging examined death rates from 1990 to 2019 in the eight longest-lived populations, plus Hong Kong and the United States. Improvements in life expectancy have decelerated since 1990. The authors estimate that survival to age 100 is unlikely to exceed 15 percent for women and 5 percent for men, and conclude that radical life extension this century is implausible unless biological ageing itself can be markedly slowed.
Hold that alongside the healthspan number and the strategy becomes obvious. The realistic prize this century is not another thirty years on the end. It is the twenty years in the middle that are currently spent unwell.
What does diet actually buy, in years?
A Norwegian group built a life table model on meta-analyses and Global Burden of Disease data, and asked what sustained dietary change is worth in life expectancy. It is the clearest quantification in the field, and the individual food groups are itemised.
| Change from a typical Western diet | Years gained, women | Years gained, men |
|---|---|---|
| More legumes | 2.2 | 2.5 |
| More whole grains | 2.0 | 2.3 |
| More nuts | 1.7 | 2.0 |
| Less red meat | 1.6 | 1.9 |
| Less processed meat | 1.6 | 1.9 |
| Full optimised diet from age 20 | 10.7 | 13.0 |
| Full optimised diet from age 60 | 8.0 | 8.8 |
Two things stand out. Beans, wholegrains and nuts do more work than any supplement has ever demonstrated, and the list is unglamorous enough that no one sells it. And starting at 60 still recovered eight years in the model. Even at 80, the estimate was 3.4 years.
These are modelled estimates, not trial results, and the authors say so. The direction and the ranking of food groups are well supported. The decimal places are not. If you want one change with the best evidence behind it in a European population, shifting the fat in your cooking towards a high polyphenol extra virgin olive oil is the Mediterranean pattern’s most studied component.
Exercise: the dose-response curve, and where it flattens
The best data here pools six cohorts, 661 137 adults with a median age of 62, 116 686 deaths, and a median follow-up of 14.2 years. It measured leisure time moderate to vigorous activity against mortality, and it found where the curve stops rising.
WEEKLY ACTIVITY AGAINST MORTALITY RISK
The shape matters more than any single figure. The biggest single gain is between doing nothing and doing something, even below the guideline. Going from the recommended minimum to three to five times it moved mortality risk from 31 percent lower to 39 percent lower, a real but modest addition. And at ten times the recommendation there was no evidence of harm, which settles an argument that ran for years.
The UK guidance is 150 minutes of moderate activity a week plus two sessions of muscle strengthening. Most British adults who are inactive would take the largest step available to them by reaching even half of that.
Social connection: the risk factor left off most lists
A meta-analytic review pooled studies published between 1980 and 2014 with mortality data. After controlling for confounders, social isolation carried an odds ratio of 1.29 for death, loneliness 1.26, and living alone 1.32. That is a 26 to 32 percent increase in likelihood of mortality.
Put beside the standard risk factors, that is not a soft finding. The effect held across gender, follow-up length and world region, and it was stronger in samples with an average age below 65. Isolation is not only an old age problem, and objective isolation and the subjective feeling of loneliness predicted death about equally.
This is the part of the longevity picture that no product addresses, which may be why it gets less airtime than it deserves. In practical terms it belongs on the same page as blood pressure.
Sleep, alcohol and the rest of the lifestyle picture
Sleep sits in an awkward place in this literature. Observational studies consistently find a U-shaped relationship, with the lowest mortality around seven hours and higher risk at both ends. Whether short sleep causes early death or reflects the illness that causes it is not resolved, and any page that tells you otherwise is overreaching. Sleep quality is also the endpoint most supplement research in this area actually reaches: the human trials on L-theanine moved self-rated sleep and stress scores, not mortality.
Alcohol has moved a long way in a decade. The old J-shaped curve, with light drinkers apparently outliving abstainers, has largely been attributed to former drinkers being counted among the abstainers. UK guidance is now no more than 14 units a week, spread over three days or more, with no level described as risk-free.
Smoking remains the single largest modifiable cause of premature death in the UK, and nothing on this page competes with stopping. If you smoke, that is the intervention. Everything else is optimisation.
What longevity medicine can and cannot do yet
The scientific framework most researchers work from lists the hallmarks of ageing: genomic instability, telomere attrition, epigenetic alterations, loss of proteostasis, disabled macroautophagy, deregulated nutrient sensing, mitochondrial dysfunction, cellular senescence, stem cell exhaustion, altered intercellular communication, chronic inflammation and dysbiosis. Twelve, in the 2023 expansion of the original nine.
That list is a research map, not a shopping list. Each hallmark has compounds attached to it in cell and animal work. Very few of those compounds have a randomised trial in humans with a mortality or healthspan outcome, because such a trial would need decades and thousands of participants. This is the honest state of the field and it is rarely stated on pages selling into it.
Chronic low grade inflammation is the hallmark with the most human data behind it, because it is measurable in blood and it tracks with almost every age-related disease. Heart disease, type 2 diabetes and dementia all sit downstream of it, which is why these diseases cluster in the same decades of life. That makes it the most sensible place to act, whether through diet, activity, sleep or a titrated anti-inflammatory formula whose amounts you can check against the trials.
The rest of the field deserves interest and scepticism in equal measure. A biological age clock is a research instrument. A longevity clinic panel is a set of measurements, not a treatment. And the fundamentals in this article, which cost nothing, still account for more years than anything currently sold as an intervention.
What does longevity mean?
An unusually long individual life. It is distinct from life expectancy, which is a population average at a given age, and from healthspan, the years lived free of serious disease. In ageing research the emphasis has shifted from longevity alone to healthy life years.
What is the difference between lifespan and healthspan?
Lifespan is how long you live. Healthspan is how much of that time is spent in good health. In England, healthy life expectancy at birth was 62.4 years for males and 62.7 for females in 2020 to 2022, against UK life expectancy of 79.1 and 83.0 years. The difference is the target of most longevity work.
How much of longevity is down to your genes?
Less than most people assume. Pedigree analysis covering hundreds of millions of people put the true heritability of human lifespan well below 10 percent once assortative mating was accounted for. Earlier estimates of 15 to 30 percent were inflated because partners resemble each other in habits and circumstances.
What are the habits most consistently linked to a longer life?
Not smoking, regular physical activity, a diet built on legumes, whole grains, nuts, fish, fruit and vegetables, keeping alcohol within 14 units a week, adequate sleep, and maintaining social connection. Each of those has mortality data behind it. Lists that add a tenth and eleventh habit are usually padding.
Is it too late to change things in your sixties?
No. In the food choices model, moving from a typical Western diet to the optimised one at age 60 was estimated to add 8.0 years for women and 8.8 for men, and 3.4 years at age 80. The gain is smaller than starting at 20, but it is not close to nothing.
Can supplements extend human life?
No supplement has been shown in a randomised controlled trial to extend human lifespan or healthspan, because such a trial would take decades. Some compounds have measurable effects on intermediate markers such as inflammation or blood pressure. That is a different and much weaker claim, and it is the only one the evidence supports.
Will people routinely live to 120?
The demographic evidence argues against it. Analysis of the longest-lived populations found that improvements in life expectancy have decelerated since 1990, and estimated that survival to 100 is unlikely to exceed 15 percent for women and 5 percent for men without a genuine slowing of biological ageing.
Sources
- Ruby J.G., Wright K.M., Rand K.A., et al. Estimates of the heritability of human longevity are substantially inflated due to assortative mating. Genetics, 2018. DOI: 10.1534/genetics.118.301613
- Olshansky S.J., Willcox B.J., Demetrius L., Beltran-Sanchez H. Implausibility of radical life extension in humans in the twenty-first century. Nature Aging, 2024. DOI: 10.1038/s43587-024-00702-3
- Fadnes L.T., Okland J.M., Haaland O.A., Johansson K.A. Estimating impact of food choices on life expectancy: a modeling study. PLOS Medicine, 2022. DOI: 10.1371/journal.pmed.1003889
- Arem H., Moore S.C., Patel A., et al. Leisure time physical activity and mortality: a detailed pooled analysis of the dose-response relationship. JAMA Internal Medicine, 2015. DOI: 10.1001/jamainternmed.2015.0533
- Holt-Lunstad J., Smith T.B., Baker M., Harris T., Stephenson D. Loneliness and social isolation as risk factors for mortality: a meta-analytic review. Perspectives on Psychological Science, 2015. DOI: 10.1177/1745691614568352
- Lopez-Otin C., Blasco M.A., Partridge L., Serrano M., Kroemer G. Hallmarks of aging: an expanding universe. Cell, 2023. DOI: 10.1016/j.cell.2022.11.001
- Office for National Statistics. National life tables, life expectancy in the UK: 2022 to 2024.
- Office for National Statistics. Health state life expectancies, UK: between 2011 to 2013 and 2020 to 2022.
This article is general information, not medical advice. Food supplements do not replace a varied diet or a healthy lifestyle. If you have a long-term condition, take prescribed medicines or are planning a significant change to your diet or exercise, speak to your GP or pharmacist first.
