Can Staying Active Help You Live Longer? What a 30-Year Twin Study Reveals About Exercise, Ageing and Mortality
- Alastair Hunt
- Apr 17
- 5 min read
Updated: Apr 23
We've long been told that regular exercise can help us live longer and age more gracefully. But is the story really that simple? A new study from Finland, published in the European Journal of Epidemiology, delves deep into this question using a unique approach - tracking thousands of twins over three decades to understand how physical activity in adulthood relates to ageing and the risk of death.
As ever, please talk to your doctor or medical practitioner most familiar with your medical history before implementing any changes in diet, exercise or lifestyle, especially if you are under treatment. Links to all studies at bottom of page.
The Study in Brief
Researchers followed 22,750 same-sex twins from the Finnish Twin Cohort, assessing their physical activity levels through three surveys conducted between 1975 and 1990. They then tracked their health and survival until 2020. For a smaller group of 1,153 participants, blood samples were analysed to determine “biological age” using cutting-edge epigenetic clocks - tools that estimate how quickly a person is ageing at the cellular level.
Participants were sorted into four groups based on their long-term activity patterns: sedentary, moderately active, active and highly active.
What They Found
At first glance, the results seem to support familiar advice: people who were moderately to highly active had lower rates of death compared to those who were sedentary. Over the full 30-year follow-up, sedentary individuals had the highest mortality, while active participants had up to a 7% lower risk. However, the deeper the researchers dug, the more complex the story became.
Biological Ageing: A Surprising Twist
When looking at biological ageing, measured through changes in DNA methylation (a chemical tag on our DNA that shifts with age), the results weren’t as straightforward as many might expect. Surprisingly, both the sedentary and highly active groups showed signs of faster biological ageing compared to the moderately active group.
This pattern persisted even after accounting for differences in education, alcohol use, smoking habits, and body weight. For instance, the highly active group was biologically 1.6 years older than the active group on average, even though they were exercising more.
Why might this be? One possibility is that extreme levels of activity place additional stress on the body, particularly the cardiovascular system. Another is that individuals in the highly active group may have underreported smoking or other lifestyle risks, which were indirectly detected through their DNA markers.
The Role of Genetics and Reverse Causality
Because the study was based on twins - some of whom were genetically identical - it offered a unique opportunity to explore whether the benefits of exercise were due to physical activity itself or to inherited traits that promote both fitness and longevity.
When researchers compared twins with different activity levels, they found little difference in mortality, especially among identical twins. This suggests that some of the observed benefits of being active might stem from shared genetics, rather than exercise alone.
Additionally, reverse causality played a role. People who were already unwell might have reduced their activity levels, meaning poor health led to inactivity, rather than inactivity leading to poor health.
Longevity Insights for the Biomarker-Minded
For readers invested in longevity, particularly those tracking biological age through epigenetic clocks like GrimAge or DunedinPACE, this study is especially relevant. While physical activity can influence these markers, the effect is not linear. In fact, the most biologically youthful profiles were seen in those who engaged in moderate levels of exercise - highlighting the importance of dosage.
These findings underscore a key principle in longevity research: balance matters. Overtraining, despite its potential fitness gains, may accelerate certain ageing pathways. The highly active group showed elevated DNA methylation signatures linked to proteins like cystatin C and beta-2-microglobulin, both of which are associated with cardiovascular and kidney stress.
In practice, this supports a shift from sheer exercise volume to a more nuanced, data-informed lifestyle - blending moderate, consistent movement with a focus on recovery, nutrition and stress management.
For those focused on longevity, the most consistently supported dose of exercise lies in the moderate-intensity range - think brisk walking, gentle cycling or Zone 2 running - performed regularly but not excessively. Research, including large-scale twin studies, suggests that around 30 to 45 minutes per day of such activity, or 2 to 4 MET hours daily, offers substantial health benefits without the potential risks associated with very high volumes. This aligns closely with the World Health Organisation's guidelines, which recommend 150 to 300 minutes of moderate-intensity aerobic activity per week.
Pushing beyond this - such as jogging more than an hour a day at moderate intensity - doesn’t seem to add further benefits and may even accelerate some ageing markers in certain individuals. For those pursuing longevity, the key is sustainability: choose an activity you enjoy, keep it regular, and prioritise recovery and balance over volume.
Final Thoughts
This study is a reminder that the path to a longer, healthier life isn’t paved by exercise alone. While being active is undoubtedly beneficial - especially when compared to a sedentary lifestyle - there appears to be a sweet spot where moderate and consistent activity slows biological ageing and reduces mortality risk.
What truly matters is an overall healthy lifestyle. That includes balanced eating, avoiding harmful habits like smoking, and yes, staying active - but in a way that’s sustainable, enjoyable and suited to your personal lifestyle. Supporting your body through balanced nutrition, physical activity, stress reduction, quality sleep and meaningful social connection (these are known as the Pillars of Health) are some of the most powerful longevity tools we have. As always, it's about progress, not perfection, and even small changes can make a meaningful difference over time.
For most people, improving health is about finding motivation and prioritising self-care - with an ultimate goal of taking action. If you want to take effective and targeted steps that fit into your unique lifestyle and circumstances, The Whole Health Practice is here to help.
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Stay Healthy,
Alastair
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Related Studies
Kankaanpää, A., Tolvanen, A., Joensuu, L. et al. The associations of long-term physical activity in adulthood with later biological ageing and all-cause mortality – a prospective twin study. Eur J Epidemiol 40, 107–122 (2025). https://doi.org/10.1007/s10654-024-01200-x
Other
Lefferts WK, Davis MM, Valentine RJ. Exercise as an Aging Mimetic: A New Perspective on the Mechanisms Behind Exercise as Preventive Medicine Against Age-Related Chronic Disease. Front Physiol. 2022 Aug 15;13:866792. doi: 10.3389/fphys.2022.866792. PMID: 36045751; PMCID: PMC9420936.
O'Keefe EL, Torres-Acosta N, O'Keefe JH, Lavie CJ. Training for Longevity: The Reverse J-Curve for Exercise. Mo Med. 2020 Jul-Aug;117(4):355-361. PMID: 32848273; PMCID: PMC7431070.
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