What scientists mean by healthy ageing

In long-term studies, healthy ageing is usually measured as reaching a certain age while staying free of major chronic conditions such as cardiovascular disease, stroke, diabetes, many cancers and severe disability. Some studies also include good mental health, preserved daily functioning and intact cognitive performance in their definitions Daskalopoulou et al. 2017, Zhang et al. 2025.

When scientists try to predict who will age well, they look at dozens of midlife variables: weight, blood markers, blood pressure, physical activity, diet, smoking, education, social connections and more. Modern analyses using methods like random forests and other machine learning techniques allow them to see which factors stand out most strongly over 20 to 30 years of follow-up.

Body weight, waist size and cholesterol: core predictors

One recent population-based cohort, followed for 30 years in the Netherlands, used a large set of biological, lifestyle and environmental variables to identify key predictors of “healthy physiological ageing”. The most important predictors that emerged were overweight-related measures (body mass index, waist circumference and waist-to-hip ratio) and cholesterol-related measures (use of cholesterol-lowering medication, HDL and total cholesterol) Loef et al. 2023.

These markers sit in the middle between behaviour and disease. Higher waist circumference, obesity, and adverse lipid profiles are well-established risk factors for type 2 diabetes, coronary heart disease and earlier mortality Assmann et al. 2017. Newer multi-cohort studies in 2025 also show that mid and late life cardiovascular indicators, including body mass index and waist size, track closely with markers of biological ageing at the cellular and organ level Asefa et al. 2025.

From a practical point of view, your long-term pattern of weight, waist size and cholesterol, interpreted with a health professional, is one of the clearest biological snapshots of how kindly, or harshly, you are likely to age.

Movement, strength and everyday activity

Physical activity is one of the most consistent predictors of healthy ageing across countries and study designs. A large systematic review and meta-analysis of cohort studies found that people with higher levels of physical activity had about 39 per cent higher odds of healthy ageing compared with inactive peers Daskalopoulou et al. 2017, a result supported by other reviews that reported similar effect sizes Yu et al. 2020.

More recent work continues to reinforce the message that it is never too late to start moving more. A large review in the British Journal of Sports Medicine showed that increasing physical activity at any point in adulthood can significantly reduce the risk of death from all causes, including cardiovascular disease and cancer BJSM 2024 summary.

Muscle strength and physical performance also matter. Newer studies that combine physical capacity tests with biological age markers show that people with stronger grip strength, better balance and greater endurance tend to have “younger” biological age profiles Tzemah Shahar et al. 2025. Separate research links cardiorespiratory fitness to lower dementia risk, even among people with higher genetic risk Wu et al. 2024.

The key message is that both structured exercise and everyday movement count. Walking, gardening, manual work, taking the stairs and active travel all contribute to better odds of ageing well.

Smoking, alcohol, diet quality and ageing well

Non-smoking status is a powerful predictor of healthy ageing. Across multiple cohorts, smoking is associated with higher mortality, more disability and faster cognitive decline, while people who never smoked have better odds of surviving to older age in good health Passarino et al. 2016.

Alcohol patterns are more nuanced. Older observational work sometimes suggested benefits of light to moderate drinking, but more recent summaries tend to conclude that less is better for cancer risk and brain health. Many long-lived traditional communities use alcohol sparingly, often as small amounts of wine with food and in social settings.

Diet quality sits near the centre of the best predictors of healthy ageing. A large study published in Nature Medicine, reported in 2025 found that people who followed a healthy dietary pattern in midlife had 45 to 86 per cent higher odds of healthy ageing in their seventies compared with those who did not. The most protective pattern, based on the Alternative Healthy Eating Index, emphasised vegetables, fruits, whole grains, nuts, legumes and healthy fats, while limiting red and processed meat, sugary drinks and highly processed foods Verywell Health 2025.

These findings echo long-standing evidence in favour of traditional Mediterranean style and plant-rich diets, which are linked to lower rates of cardiovascular disease, better metabolic health and longer life expectancy.

Social connections, purpose and long-term health

Healthy ageing is not only about biology and individual behaviour. The quality of social relationships and a sense of meaning in life are also important predictors. Large cohort studies have shown that people with stronger social ties and perceived social support are more likely to survive to older ages in good health, even after accounting for smoking, body weight and physical activity Tang et al. 2024.

Public health research increasingly highlights “polysocial” scores that combine family ties, friendship networks, community participation and social support. In UK Biobank data, a healthy lifestyle was associated with lower mortality across all levels of social connectedness, but the benefits were often strongest among those with fewer social resources Tang et al. 2024.

For people who participate in volunteering, hosting or intercultural projects, this is encouraging. These activities naturally build social ties, shared routines and a sense of purpose, which are exactly the kinds of experiences that seem to support better ageing outcomes.

Brain health, education and cognitive reserve

One reason some people keep a sharper memory into their eighties or nineties is the idea of “cognitive reserve”. This term refers to mental resources built up across life through education, mentally demanding work, creative hobbies and complex leisure activities. People with higher cognitive reserve tend to show later or milder symptoms of cognitive decline for the same amount of brain pathology.

Observational studies have consistently found that higher educational attainment, continued learning and regular engagement in mentally stimulating activities are associated with better late-life cognition and slower decline Passarino et al. 2016. Combining physical activity with cognitive challenges and social interaction seems particularly promising for supporting brain health in older age.

Newer work on organ-specific biological ageing suggests that the brain may be especially important. A 2024 study using blood-based protein signatures to estimate organ age reported that faster brain ageing was strongly linked to increased risk of death and a higher likelihood of developing Alzheimer’s disease Wyss Coray et al. 2024. This fits with the idea that supporting brain health through movement, learning, and social life is central to ageing well.

Genetics, biological clocks and what you can influence

Genetics do play a role in ageing, but less than many assume. Family and twin studies converge on the idea that roughly a quarter of the variation in human longevity is due to genetic differences, with the rest linked to health behaviours, exposures and chance Melzer et al. 2019, Passarino et al. 2016.

A widely discussed analysis of 353,742 adults in the UK Biobank, reported in 2024, found that people with high genetic risk for a shorter lifespan had a 21 percent increased risk of early death compared with those with lower genetic risk. People with an unhealthy lifestyle had a 78 percent higher risk, independent of genetics, and a favourable lifestyle could offset roughly 60 per cent of the genetic risk and add about five years of life expectancy at age 40 The Guardian 2024.

Modern “biological age clocks”, including epigenetic clocks based on DNA methylation, also support the impact of lifestyle. Faster ticking of these clocks is associated with higher disease risk and mortality, and is linked to smoking, obesity, poor diet and inactivity, while healthier habits tend to correlate with slower biological ageing Joshi et al. 2017.

Environment, inequality and the bigger picture

Individual choices are shaped by wider systems. People living in safer neighbourhoods with walkable streets, access to healthy food, clean air and supportive healthcare have a much easier time scoring well on the best predictors of healthy ageing.

Current projects using large biobanks are investigating how lifestyle and gene environment interactions shape healthy longevity over time UK Biobank 2025. Their early findings suggest that supportive environments and health-promoting policies can help many people benefit from the same protective habits, regardless of genetic background.

For communities built around volunteering, eco projects and intercultural exchange, there is an opportunity to create small, health-supporting environments: shared meals, active days, low reliance on ultra-processed food, regular social contact and time spent outdoors.

Putting the best predictors of healthy ageing into practice

When you put this research together, a simple picture appears. The best predictors of healthy ageing include metabolic health and body weight, especially around the waist, regular physical activity and muscle strength, non-smoking status, low-risk drinking patterns, a plant-rich and minimally processed diet, strong social connections, a sense of purpose and ongoing learning or mental stimulation.

Genetics and luck still play a part, and no predictor can guarantee a specific outcome. Still, people who do well on these variables are more likely to reach older age with better health and function. The encouraging part is that most of these predictors can be shaped, little by little, through daily routines and through the kinds of meaningful projects that bring people together.

Volunteering, hosting and long-term cultural exchanges are not magic solutions, but they often bundle many of these elements into one experience: movement, shared meals, social bonds, language learning and problem solving. In that sense, they can be one practical way to align everyday life with what science is learning about how we age.

References

1. Melzer D, Pilling LC, Ferrucci L. The genetics of human ageing. Nat Rev Genet. 2019. Available at: https://pmc.ncbi.nlm.nih.gov/articles/PMC9934000/
2. Vaupel JW et al. Genetic influence on human lifespan and longevity. 2006. Available at: https://www.demogr.mpg.de/publications/files/2942_1202133488_1_fulltext.pdf
3. Loef B et al. Predictors of healthy physiological ageing across generations in a 30-year population-based cohort study. 2023. Available at: https://pmc.ncbi.nlm.nih.gov/articles/PMC9948415/
4. Daskalopoulou C et al. Physical activity and healthy ageing: a systematic review and meta-analysis of cohort studies. Ageing Research Reviews. 2017. Available at: https://www.sciencedirect.com/science/article/pii/S1568163717300302
5. Yu R et al. A systematic review and meta-analysis of cohort studies on physical activity and successful ageing. Aging. 2020. Available at: https://www.aging-us.com/article/103057/text
6. Verywell Health. Adopting a healthy midlife diet may help you age better in your 70s, study finds. 2025. Available at: https://www.verywellhealth.com/midlife-diet-11704292
7. The Guardian. Healthy lifestyle may offset genetics by 60% and add five years to life, study says. 2024. Available at: https://www.theguardian.com/science/2024/apr/30/healthy-lifestyle-may-offset-genetics-by-60-and-add-five-years-to-life-study-says
8. Wu W et al. Physical fitness can lower risk of dementia, research finds. Summary in The Guardian, 2024. Available at: https://www.theguardian.com/society/2024/nov/19/physical-fitness-can-lower-risk-of-dementia-research-finds
9. UK Biobank. Lifestyle, genetic disposition and healthy longevity. Project description, 2025. Available at: https://www.ukbiobank.ac.uk/projects/lifestyle-genetic-disposition-and-healthy-longevity/

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