by Claire Richardson, Health Scientist behind Second Prime®, December 2025
January is the month we promise ourselves all sorts of things: more steps, less sugar, fewer late nights. Underneath many of those resolutions sits a quieter hope, not just to live longer, but to stay well for as much of that time as possible.
We now have a language for that hope. “Lifespan” is how many years we live. “Healthspan” is how many of those years we spend with enough physical and mental reserve to do the things that matter to us. In the UK, average life expectancy is still around 81, but the number of years lived in good health has stalled or even slipped back. For many people, roughly the last fifth of life is now spent in poor health.
Put bluntly, we are adding years to life, but not reliably adding life to those years. As someone who has spent much of my career in health and research, from NHS research leadership into ageing science and preventative care, I would argue that closing this gap is one of the defining challenges facing people in midlife today.
You have more than one age
For most of history, age has been a simple question: how many birthdays have you had? Over the past decade, research has shown that we all carry several different “ages” inside us.
Scientists studying epigenetics (the chemical tags on our DNA that influence which genes switch on or off) have shown that these tags change in fairly predictable ways as we get older. By measuring them, they can estimate a person’s biological age: how “worn” their body appears to be, compared with the average for their birth year.
Other researchers have taken a broader view, looking not just at DNA but at patterns across blood tests, blood pressure, kidney function, inflammation, muscle strength and more. What emerges is a picture of multi-system ageing. Where, instead of one organ failing suddenly, several systems drift gradually out of their ideal range together, for example; a little higher blood sugar here, a little more inflammation there, slightly poorer sleep, slightly less muscle.
A useful analogy is an orchestra. Ageing is less like one violin snapping a string, and more like more and more instruments slipping a little out of tune. The music suffers long before anything actually breaks.
The “use it or lose it” advanced anti-ageing problem, and why it’s good news
The slightly uncomfortable truth is that many of these anti-ageing changes are linked to how we live in our forties, fifties and sixties.
Long-running studies suggest that about half of the difference in how long and how well people live can be traced back to behaviour and environment: how much we move, whether we smoke, what we eat, how well we sleep, how much alcohol we drink and how connected we are to other people.
Muscle and bone are a clear example. For years we thought that loss of strength and bone density was simply “inevitable” with age, especially for women after the menopause. Newer clinical trials tell a more hopeful story. Structured strength programmes, started even in the late 60s or early 70s, can not only slow bone loss but actually add bone density at key sites like the hip and spine, while increasing muscle mass and balance. That translates into fewer falls, fewer fractures and more independence.
In other words, “use it or lose it” is not a slogan, it is a mantra for longevity. Systems that are regularly used and challenged (muscles, bones, the brain, the heart and lungs) tend to keep more of their capacity. Systems that are neglected tend to decline faster.
As a former performance swimmer and long-distance open-water athlete, I have seen both sides of this first-hand. When I am training hard for a Channel-length swim, I am reminded how responsive the body still is, even in midlife. When I am pulled into too many meetings and not enough movement, I feel how quickly stamina, mood and sleep quality begin to slip. The research simply confirms what many people sense in their own lives: use it, and you really do keep more of it.
Your “second heart” and other unglamorous superpowers
Some of the most powerful levers are also the least glamorous.
Take the so-called “second heart” in your calves. Every time you move your ankle or push through your toes, the muscles in your lower leg squeeze blood back up towards your heart against gravity. When this calf pump is strong and active, (because you walk regularly, take the stairs, or do simple heel raises), it supports healthy circulation. When it is weak or switched off for long periods by sitting, blood tends to pool in the lower legs, which can contribute to swelling, varicose veins and, over time, higher cardiovascular risk.
No supplement or gadget can do that job for you. Only movement can.
We see similar patterns in the brain. Midlife MRI studies show that better cardiovascular fitness; think brisk walking up Cleeve Hill, a regular swim at the lido, or a decent bike ride, is linked to healthier “wiring” in the brain’s white matter. That wiring supports memory, attention and speed of thinking. Again, the people who benefit are not professional athletes; they are ordinary adults whose hearts and lungs are kept reasonably fit on a weekly basis.
The same applies to cognition itself. People who continue to stretch their skills, learn new things and stay embedded in work or community roles that challenge them tend to maintain their thinking abilities better than those who drift into permanent “autopilot”.
Taken together, the message is simple: your everyday choices are either gently training your future self, or quietly de-training them.
The stories we tell ourselves about getting older
There is also a psychological side to all of this. Research from European ageing studies suggests that how we picture our older selves shapes how we behave now. People who see later life purely as decline are less likely to invest in their health, finances and relationships. Those who see it as a stage with potential for growth and contribution are more likely to take practical steps to prepare.
In my own work, from early research on cold-water swimming for mental health in North Devon, through years in commercial and NHS research, to my current doctoral work on ageing and the Second Prime® system, I see this pattern repeatedly. Some people arrive in their late forties or early fifties saying “I feel ten years older than I am”. Others say, “I want to be hiking or swimming in my seventies so what do I need to put in place now?” The test results may look similar; the mindset and trajectory are very different.
Part of the work of healthy ageing, then, is to update the story in our heads. Getting older is unavoidable. Becoming unwell earlier than necessary is not.
Sorting the signal from the noise
With so much information, and marketing, around longevity, how do you know what is worth paying attention to?
Across my research and practice, three themes stand out:
- Movement is medicine. Cardiorespiratory fitness and strength are consistently linked to longer healthspan and a lower risk of disability, even when started in midlife or later.
- Systems age together. Focusing on a single “magic number” like; cholesterol, weight, or an off-the-shelf biological age score, rarely tells the whole story. It is the overall pattern across systems that matters.
- Personal context counts. The right plan for a 50-year-old woman juggling work, teenagers and ageing parents in the Cotswolds will look very different to the right plan for a semi-retired man in his early 70s. The principles are the same; the application is not.
Second Prime®, the system I have developed as part of my doctoral research, is essentially a way of making sense of that complexity. It treats ageing not as a single curve but as several interacting domains; movement and metabolism, cognitive load, gut–brain signalling, hormones and identity, and asks which of those seem to be ageing fastest in a particular person. That is where effort, and support, are likely to have the greatest impact.
Your Second Prime®
If there is a single thought I would leave you with for the new year, it is this:
You cannot control everything about how you age, but you can control far more than you have probably been led to believe.
Healthy ageing is not about chasing extreme longevity or the latest anti-ageing fad. It is about protecting your strength, your mobility, your brain and your sense of self so that you can keep doing the things you care about, for longer.
That, in essence, is what I mean by your “Second Prime”: a deliberate decision about how you want the second half of your life to feel, and a willingness to start acting on that decision now, while the returns are still at their highest.
Claire Richardson is a health scientist, creator of the Second Prime® system and CEO of GHS Clinics in Cheltenham. You can find her at www.ghsclinics.health and on LinkedIn.