Muscle and Longevity: Why the Most Important Strength You’ll Build Is Invisible by Jayney Goddard MSc, PG Dip Ed, FCMA, FRSM. Founder and President, The Complementary Medical Association (The CMA)
There is a peculiar blind spot at the heart of the longevity movement. We track our sleep with rings, our glucose with patches, our biological age with blood panels. We buy the supplements, the cold plunges, the red-light panels. And almost none of it touches the single tissue that the evidence keeps pointing to as the most reliable lever we have over how long, and how well, we live.
That tissue is muscle. And the reason we ignore it is, I think, that we have profoundly misunderstood what it is for.
We think of muscle as something aesthetic – the visible architecture of a body that looks after itself. Or we think of it as merely mechanical: the thing that lets us carry shopping and climb stairs. Both are true and both miss the point entirely. The most important things muscle does for you cannot be seen at all. They happen at the level of your bloodstream, your bones, your brain, your metabolism. The strongest thing you will ever build is, in the most literal sense, invisible.
Muscle is an organ that talks to the rest of you
For most of the twentieth century, skeletal muscle was understood as a kind of biological scaffolding – important for movement, otherwise inert. That picture began to collapse around the turn of the millennium, when researchers discovered that contracting muscle releases signalling proteins into the circulation. These were named myokines, and the term itself only entered the literature in 2003.
What followed has quietly reshaped how physiologists think about the body. Muscle, it turns out, is an endocrine organ – one that secretes hundreds of these small proteins in response to contraction, with receptors waiting for them on fat, liver, pancreas, bone, heart, immune cells and brain.1 In other words, when you work a muscle, you are not just strengthening that muscle. You are sending chemical messages to nearly every system you possess.
Some of these messengers help regulate blood sugar. Others appear to dampen inflammation, support tissue repair, and influence how your immune system behaves. The implication is striking: a great deal of what we vaguely call “the benefits of exercise” may be the downstream effect of muscle doing its job as a secretory organ.2 Movement is not merely burning energy. It is a conversation your body is having with itself – and muscle is doing most of the talking.
This is why the aesthetic framing does such damage. It encourages us to treat muscle as optional decoration, something for the gym-obsessed or the vain, when in fact it is functioning as one of the most active and influential glands in the human body.
What the strength-and-mortality data actually shows
If muscle were merely cosmetic, it would not predict death. It does – and with a consistency that ought to be far better known.
The most quietly devastating piece of evidence comes from the Prospective Urban Rural Epidemiology study, which followed nearly 140,000 adults across seventeen countries. The researchers used one of the simplest measures imaginable: grip strength, taken with a hand-held device. The finding was that every five-kilogram reduction in grip strength was associated with a measurable rise in the risk of dying – roughly a sixteen per cent increase in all-cause mortality, alongside raised risk of cardiovascular death, heart attack and stroke. Grip strength turned out to be a stronger predictor of death than systolic blood pressure.3
Sit with that for a moment. We screen blood pressure routinely, as we should. Yet a crude measure of muscular strength – something you could assess in a doctor’s waiting room in thirty seconds â- carried more predictive weight. The accompanying commentary in the journal put it about as plainly as scientists ever do: there can be little doubt that grip strength predicts future mortality, and that losing it may be a particularly good marker of the underlying ageing process itself.4
Now, an honest word about what this does and does not mean. These are observational findings, and grip strength here is acting as a proxy – a visible readout of the body’s overall muscular and physiological reserve. Weak grip does not reach out and cause a heart attack. The researchers themselves were careful to say that we still need to establish whether deliberately building strength reduces these risks, rather than simply tracking them. I want to be scrupulous about that, because the longevity world is awash with people overstating exactly these kinds of data.
But here is what we can say with confidence: strength is a window onto something real and important about your body’s resilience. And unlike your chronological age or your genes, it is something you can change.
The decline is not destiny – but it is happening quietly
The uncomfortable backdrop to all this is that muscle quietly leaves us as we age. The clinical term is sarcopenia – the progressive loss of muscle mass and strength over the years – and its consequences are not abstract. They are the loss of independence, the fall that becomes a fracture, the slow narrowing of a life.
What makes sarcopenia so insidious is its invisibility, again. It does not announce itself. It is not painful. For many people the first real signal is a stumble, or the day a familiar task suddenly feels hard. By then a good deal of ground has been lost – and lost ground, in muscle, is harder to recover with each passing decade because the body becomes less responsive to the signals that build it. Physiologists call this anabolic resistance: as we age, muscle becomes a little deaf to the cues – protein, exercise – that once made it grow.5
This is not a counsel of despair. It is the opposite. It is the single best argument for treating strength as something you build now, deliberately, as an investment – rather than something you hope to still have later.
What actually builds it
The honest answer is unglamorous, and that is rather the point. There is no supplement, no device, no hack. There are two levers, and they work together.
The first is resistance training – asking your muscles to work against meaningful load. This is the stimulus; without it, the rest does little. It does not require a gym full of machinery or anything that looks like bodybuilding. It requires progressively challenging your muscles, regularly, with enough effort that the last repetitions are genuinely hard. For most people new to it, the transformation in how their body feels within a few months is the most persuasive evidence they will ever encounter.
The second is adequate protein – the raw material. And here the standard advice is, for older adults, simply wrong. The official recommended intake of around 0.8 grams of protein per kilogram of body weight was never designed with the ageing muscle in mind. The expert consensus for healthy older adults now sits considerably higher – broadly in the region of 1.2 to 2.0 grams per kilogram per day – precisely to overcome that anabolic resistance.6 The two levers are not additive but multiplicative: protein without the training stimulus does little, and training without the building blocks is a frustration. Together, they are how muscle is made.
A note for those of us who eat plant-based, as I do: the research is candid that plant proteins can be slightly less efficient at triggering muscle synthesis, gram for gram, largely because of their amino acid profiles. This is not an argument against a vegan diet – it is an argument for being deliberate about it: eating enough total protein, drawing from a range of sources across the day, and ensuring meals carry a genuine protein load rather than a token one. Treated thoughtfully, a plant-based diet is entirely compatible with building and keeping strength. Treated carelessly – by anyone, on any diet – protein is the thing most easily left short.
Reframing strength
I think the deepest shift here is not practical but conceptual. We have been sold strength as vanity, when it is in fact one of the most profound forms of self-care available to us – and one of the few that genuinely compounds over a lifetime.
The muscle you build is doing work you will never see. It is steadying your blood sugar, signalling to your bones to hold their density, sending anti-inflammatory messages through your bloodstream, and quietly widening the margin of resilience you will draw on in the decades to come. It asks for nothing exotic. It cannot be bought. It can only be earned, and re-earned, through the unfashionable act of regularly asking your body to do something hard.
In a wellness culture forever chasing the next visible marker, there is something almost subversive about investing in the one thing that does its most important work entirely out of sight. The strongest thing you will ever build is invisible. It is also, I would argue, the truest measure of whether you are caring for the body you actually have to live in – not for a year, but for the long, full life that good fortune and good sense might yet allow.
Please let me know below what you think of the article and whether you have any questions for me at all.
Love and health,
Jayney XOXO
References
- Pedersen BK, Febbraio MA. Muscles, exercise and obesity: skeletal muscle as a secretory organ. Nature Reviews Endocrinology. 2012;8(8):457–465. https://www.nature.com/articles/nrendo.2012.49 ↩
- Severinsen MCK, Pedersen BK. Muscle–organ crosstalk: the emerging roles of myokines. Endocrine Reviews. 2020;41(4):594–609. https://academic.oup.com/edrv/article/41/4/594/5835999 ↩
- Leong DP, Teo KK, Rangarajan S, et al. Prognostic value of grip strength: findings from the Prospective Urban Rural Epidemiology (PURE) study. The Lancet. 2015;386(9990):266–273. https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(14)62000-6/abstract ↩
- Sayer AA, Kirkwood TBL. Grip strength and mortality: a biomarker of ageing? The Lancet. 2015;386(9990):226–227. https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(14)62349-7/abstract ↩
- Deutz NEP, Bauer JM, Barazzoni R, et al. Protein intake and exercise for optimal muscle function with aging: recommendations from the ESPEN Expert Group. Clinical Nutrition. 2014;33(6):929–936. https://pubmed.ncbi.nlm.nih.gov/24814383/ ↩
- Bauer J, Biolo G, Cederholm T, et al. Evidence-based recommendations for optimal dietary protein intake in older people: a position paper from the PROT-AGE Study Group. Journal of the American Medical Directors Association. 2013;14(8):542–559. https://pubmed.ncbi.nlm.nih.gov/23867520/ ↩
This article is for general information and reflection. It is not medical advice, and individual circumstances vary – particularly where existing health conditions, kidney function or medication are concerned. Do consult an appropriate professional before making significant changes to how you train or eat.
