VO2 Max, Grip Strength, DEXA: The Numbers That Actually Predict Healthspan

Modern diagnostics can measure almost anything, which is exactly the problem. The traveller emerging from a full assessment holds a dossier of hundreds of values — and the quiet secret of longevity medicine is that a short, unglamorous list predicts far more than the rest of the document combined. These are the numbers our physicians return to first when a client’s diagnostic journey concludes, and the ones worth understanding before any results consultation anywhere. None requires a tunnel or a contrast injection. All of them can be improved — which is, in the end, why they matter.

VO2 max: the engine’s honest size

VO2 max — the body’s maximal rate of oxygen use — is the single most powerful routine predictor of long-term mortality that medicine currently measures. The gradient in large studies is stark: moving from low fitness to merely moderate fitness is associated with risk reductions that no pill on the market approaches, and the benefit keeps climbing into the highest tiers. Two practical notes. First, measurement quality matters enormously: the true test is a maximal effort on a treadmill or bike with a mask measuring gases — unpleasant, brief and gold-standard — while watch estimates are directionally useful and flattering by design. Second, the number responds to training at any age; it is a report card, not a sentence. A proper lab test, repeated annually, is among the highest-value hours in the entire diagnostic repertoire.

Grip strength: the strange little oracle

That a hand squeezing a dynamometer should predict mortality, cardiovascular events and future disability sounds like folklore; it is in fact one of the most replicated findings in ageing research. Grip is not magic — it is a proxy for total-body muscle mass and neuromuscular quality, which is what actually does the predicting. The measurement takes thirty seconds and costs nothing, which is why its absence from a programme tells you something about the programme. The deeper point it gates into is strength as an organ of longevity: muscle is the metabolic sink that disposes of glucose, the armour that turns a fall into a bruise instead of a fracture, and the reserve that decides how you weather illness. The oracle is only reporting on the armoury.

DEXA: the body’s true ledger

The bathroom scale reports a single number and conceals everything interesting inside it. A DEXA scan — minutes long, radiation dose trivial — opens the ledger: bone density, lean mass by limb, fat mass and, critically, visceral fat, the metabolically loud tissue around the organs that external appearance hides completely. The two findings that most often redirect a client’s year are silent ones: bone density drifting toward osteopenia a decade before anyone would guess — women especially, and earlier than commonly assumed — and normal-weight travellers carrying surprising visceral stores, the classic “thin outside” pattern. Like the fitness numbers, DEXA compounds in series: one scan is a snapshot; annual scans are a trend, and trends are where decisions live.

The supporting cast

Around the headline three, a short supporting cast completes the picture at minimal cost. Blood pressure, measured properly and repeatedly — still the most consequential number most people track carelessly. The metabolic panel — fasting glucose, HbA1c, insulin where offered — because metabolic drift is the slow engine behind so much else. ApoB, quietly replacing ordinary cholesterol among lipid specialists as the better single count of the particles that actually injure arteries. And a pair of unglamorous functional tests — walking speed and the ability to rise from a chair without hands — which sound trivial at fifty and predict independence at eighty. A programme measuring these plus the headline three, and explaining them well, is doing more for your next twenty years than any single spectacular image.

What moves the numbers

The list’s deepest virtue: everything on it responds to behaviour, and the prescriptions are almost embarrassingly classical. VO2 max rises on a base of steady sub-maximal work — the unhurried zone-two hours — sharpened by small weekly doses of genuinely hard intervals; gains arrive within months at any starting age. Grip and the muscle it reports on answer to progressive resistance training two or three times a week, plus protein in amounts most travellers under-eat, and the response persists into the ninth decade — the literature on late-life strength training is among the most optimistic in all of medicine. Bone answers to loading: impact and resistance, begun before the DEXA report turns stern. Visceral fat is the most responsive of all — it yields to the same metabolic housekeeping that improves the blood panel. None of this is news; what the numbers add is specificity and a scoreboard, which is the difference between advice and a programme.

Why travel for numbers you could get at home?

A fair question with a practical answer: in principle, nothing here requires an airport — in practice, almost nobody assembles it at home. The gas-exchange VO2 test lives in scattered performance labs; DEXA sits in clinics that never see your bloods; no one physician holds the whole picture, and so no one composes it into a plan. The best programmes abroad measure everything under one roof in days, interpret it as one story, and — the part home care does worst — attach a written plan with a date to re-measure. Compression, coherence and comparison; the case we made at greater length in The Health Check Abroad. And where the more argued-over tests belong in the mix, we have taken up separately in our honest look at full-body MRI.

The Journal shares the perspective and research method of the Longevity Jetset concierge desk. It is editorial commentary, not medical advice, and no clinic mentioned here has paid for or reviewed its inclusion — that is rather the point of us. For guidance matched to your own goals, begin a conversation.