The best-evidenced number in any premium health check is the one nobody markets

Preventive medicine sells resolution. Whole-body MRI, 230 biomarkers, 170 genes, tumour DNA in blood. The measurement with the strongest mortality evidence behind it involves a mask, a bicycle and about twenty minutes of discomfort, and it appears in roughly half the programmes we have catalogued.

Cleveland Clinic researchers analysed 122,007 adults who completed treadmill exercise testing between 1991 and 2014, following them for a median of 8.4 years.1 Cardiorespiratory fitness was inversely associated with all-cause mortality across the whole distribution. The least-fit group carried roughly five times the death risk of the elite-fit group after adjustment.

Two features of that result matter more than the headline ratio.

There is no ceiling

Most risk factors plateau. Blood pressure below a certain point stops buying you anything, and there is a point past which lowering LDL further produces diminishing returns. Fitness did not behave that way. Extreme cardiorespiratory fitness, defined as two or more standard deviations above the mean for age and sex, was associated with the lowest risk-adjusted all-cause mortality of any performance group, with no observed upper limit of benefit.1

The benefit held where caution is usually advised

The association persisted in older patients and in those with hypertension. These are the two groups most often counselled toward moderation, and in this dataset they were the groups where high fitness was associated with the largest survival difference.1

Fitness is the only variable in a premium health check that is both strongly prognostic and reliably modifiable. Almost everything else is one or the other.

Why this grades B rather than A

Grade A requires replicated randomised evidence of benefit on a hard outcome. What exists here is observational, from very large cohorts with long follow-up and consistent effects, which is grade B territory in our scheme.

The distinction is worth being precise about, because it is the same distinction that limits every other measurement in preventive medicine. The evidence establishes that fitness predicts mortality. It does not establish that measuring fitness improves mortality. Nobody has randomised people to being told their VO₂ max. What separates this from a whole-body MRI is that the downstream action is obvious, the action has its own trial evidence, and the measurement is sensitive enough to show whether the action worked. None of those three things is true of most of the panel.

What this says about how programmes are built

Fewer than half the providers in the Baseline Index include a cardiopulmonary exercise test. Among those that do, YEARS in Berlin is the clearest case: it places spiroergometry in the €1,900 Core programme, the tier that contains no imaging, no liquid biopsy and no genetics.4 In other words the cheapest thing it sells is built around the best-evidenced measurement in the category, and the expensive modalities sit above it. Biograph includes VO₂ max in both memberships, as do Everlab in Melbourne, Fountain Life, and Preventicum in Essen. The imaging-led providers, including Prenuvo and OneMRI, do not, which follows from what they are: imaging businesses. Neko Health, whose entire pitch rests on measuring the well-evidenced things cheaply, does not include it either, which is the more surprising omission.

The pattern says something about how these programmes get designed. A CPET costs a fraction of an MRI and is harder to photograph. It requires a technician, twenty minutes of a patient’s maximal effort, and a physician who can interpret a ventilatory threshold. It does not produce an image anyone wants to look at.

If you are choosing between two programmes at a similar price and one includes ergospirometry, that is a reasonable tiebreaker, and a better one than the biomarker count. It is also the question worth asking of any entry tier: a €1,900 programme with a cardiopulmonary exercise test in it is doing more evidenced work than a €1,900 programme with a scan in it.

What would change the grade

A randomised trial of fitness testing plus a structured exercise prescription against usual care, with a mortality or major cardiovascular event endpoint, would move this to A given the effect sizes already observed. Such a trial is feasible, considerably cheaper than an imaging trial, and nobody is running it.