Only a modest share of how long you live is inherited: about 20–25% in the Danish twin research (Herskind and colleagues, Human Genetics, 1996), and lower still in Ruby and colleagues’ 2018 family-tree analysis in Genetics. The rest is built. What fills the gap is not one heroic habit but your body’s daily capacity to adapt and recover, and your nervous system governs that capacity. Ageing well, in practical terms, means protecting the distance between what a day asks of you and what you can still deliver.
What actually wears out with age, the muscle, or the wiring?
We picture ageing muscle as a slow shrinking. The wiring changes first. Every muscle is run by motor units: one nerve cell in the spinal cord, plus the bundle of fibres it commands. From midlife onwards those spinal motor neurons are gradually lost, and the fibres they abandon get rescued by neighbouring neurons that sprout new branches to adopt them. The muscle mostly survives; the control gets coarser. A neuron that once commanded a small bundle of fibres may end up commanding a far larger one, so force arrives in bigger, blunter increments. That is why the earliest change shows up as wobble rather than weakness, the lowering onto a chair that turns into a small drop for the last few centimetres.
The fibres that fade first are the fast ones. Type II fibres, recruited for speed and power rather than endurance, shrink earlier and faster than the slow ones. Slow, grinding strength holds up reasonably well into later decades; power, meaning force delivered quickly, falls away considerably sooner. Nearly every task that suddenly feels harder is a power task rather than a strength task: standing up, catching your balance off a kerb, putting a hand out to break a fall.
The third change is sensory, and the one people never hear about. Muscle spindles and joint receptors, your body’s position sensors, thin out and lose sensitivity. The brain’s internal map of where your limbs are drops in resolution, and it compensates the way anyone does with poor information: by tightening up. Co-contraction, bracing opposing muscles at once, buys stability at the price of energy and fluency. It is why an older gait tends to look careful rather than frail.
Why is getting off the floor harder than it used to be?
Sit on the floor with a grandchild for twenty minutes and the getting up will tell you more than any birthday. The quick scan of the room for a coffee table to plant a hand on. The decision about which knee leads. The pause halfway, on one knee, whilst everything else catches up. Very little of that is thigh strength. It is coordination under load: hips, ankles, trunk and balance all arriving in the right order.
Claudio Gil Araújo and colleagues in Rio de Janeiro built a test out of exactly this moment. In a study of 2,002 adults aged 51 to 80, published in the European Journal of Preventive Cardiology in 2014, participants were asked to sit down on the floor and stand back up again using as little support as possible. Each person started with ten points and lost one for every hand, knee, forearm or leg used as support. Over a median of six years of follow-up, those scoring in the lowest band were several times more likely to die during the study period than those scoring 8 or above, and the association held after adjusting for age, sex and body mass index.
One ordinary movement gathers strength, balance, flexibility, coordination and body composition into a single action, which is why it summarises so much. What it does not show is that practising the movement adds years. This was observation, not an experiment: the score reports on the state of the system rather than creating it.
What do the stairs with the shopping tell you?
The other everyday audit happens between the car and the kitchen. Two bags, an uneven load, and a rail you cannot reach because both hands are full. The honest part is the breath at the top, not how hard it got, but how fast it settles. Recovery speed, not peak effort, is what tracks your reserve.
Grip strength turns out to be a strangely powerful marker of that same underlying capacity. Darryl Leong and colleagues measured it in 139,691 adults across 17 countries for the PURE study, published in The Lancet in 2015. Over roughly four years, each 5-kilogram fall in grip strength was associated with a 16% higher risk of death from any cause, and grip predicted cardiovascular death more strongly than systolic blood pressure did. Grip matters not because the hand matters, but because it is a cheap window onto total motor output: how much of the nervous system’s drive still reaches muscle.
Where does the nervous system actually come in?
Physiologists have a word for the narrowing: homeostenosis, the shrinking of the gap between what your body does at rest and what it can summon when pressed. That gap is your reserve, and two measurable things quietly close it. The first is heart-rate variability, the beat-to-beat variation reflecting the vagus nerve’s braking influence on the heart, which declines steadily across adult life. A heart that beats at exactly the same interval every time is not calm; it is unresponsive. The second is the daily cortisol curve. The sharp rise after waking and the deep trough at night both flatten with age, so the signal separating go from repair loses its edges, and a body that cannot cleanly tell the two apart spends a little of each on both.
That is the sense in which your nervous system sets the pace: not by making tissue younger, but by deciding hour by hour how much of the day’s budget goes to defence and how much to repair. Stay in defence long enough and the bill arrives as the ordinary wear of decades.
What can I do about it today, for free?
- Get on the floor once a day, and get back up. Not as exercise, as a habit. Vary the route: cross-legged, one knee, side-sitting. Rehearsing several ways up keeps the options available.
- Train the descent, not just the rise. Lower yourself into a chair over a slow count of four. Lowering is where type II fibres do their work.
- Five sit-to-stands, no hands, twice a day. Off any dining chair, arms folded across the chest so the legs cannot be bailed out.
- Carry the shopping in one trip, on purpose. Loaded carries train grip, trunk and breathing together, which is how they are used.
- Balance on one leg whilst you brush your teeth, eyes closed for the last few seconds. Removing vision hands the job back to the spindles and joint receptors.
Which everyday levers matter most?
- Movement, the only input that directly maintains motor units.
- Connection, in the Harvard Study of Adult Development, the quality of close relationships stood out as the strongest predictor of health and happiness in the later decades (Waldinger and Schulz, 2023).
- Sleep, where tissue repair and the clearing of metabolic waste actually happen.
- Purpose, having a reason to get up tends to travel with better health in the later years.
- A regulated nervous system, the thread running through all four of the above.
How does Diskin Life approach ageing well?
Everyone is offered a Discovery Session first, before committing to anything. The work itself starts with the Life Assessment, a seven-point, Whole-Person look at how your nervous system is currently running. Depending on what Dr Ari judges clinically relevant for you, that may draw on its seven extraordinary measures; not everybody has every scan. Care is gentle, hands-on Nervous System Adjustments. Every client is also included in the 13 Vitality By Design presentations, which move through four themes in sequence: Respond Better, Move Better, Eat Better and Think Better. The goal we work towards is Premium Vitality, not just more years, but more life inside them.
What if the body is not simply running down?
Forty years of Chiropractic practice and more than 25,000 people tend to change how ageing looks. What comes into view is not a body running down, but a body with a profound, largely untapped capacity to regulate and thrive, at every age. Ageing well is not about clinging to who you were. It is about establishing new neurological patterns: new pathways, new potential, new opportunities. Which is why the work here does not stop at feeling better. The aim is to keep going, towards performing freely and living vibrantly, for as long as life allows.
An honest limitation
Almost everything above is observational. The floor-rise and grip-strength findings are strong associations, not proof of cause: people who struggle to get off the floor may already carry undiagnosed illness, and that illness, not the movement, may be doing the work in the numbers. Heart-rate variability declines with age reliably, but no single intervention has been shown to reset an ageing trajectory, and none of this predicts an individual. Chiropractic care is not an anti-ageing measure and should never be presented as one. What holds honestly is that adaptability is trainable, the inputs that build it are free, and nervous-system regulation is one sensible part of a much larger picture.
Worth remembering
- The large majority of how long you live is shaped by how you live, not by inherited genes.
- Ageing shows up in the wiring before the muscle: motor-unit loss, fading fast-twitch power, and lower-resolution position sense.
- Everyday capacity tests, the floor rise, the stairs with the shopping, track real physiological reserve better than age does.
- Recovery speed, not peak effort, is the number worth watching, and it is the number your nervous system governs.
General information only, not a diagnosis or personal health advice. For questions about ageing and your health, please also speak with your GP.