What your annual check-up is not telling you

Most people over 40 have sat in a GP surgery, received the reassuring news that their cholesterol is 'fine' and their blood sugar 'normal', and walked out feeling vaguely relieved — yet still aware that energy isn't what it was, recovery takes longer, and something in the background has quietly shifted. The annual check-up passed. The body's trajectory did not.

The difficulty is that standard NHS Health Checks were built to catch disease at the threshold, not to map the slower drift happening a decade before that threshold arrives. Fasting glucose and total cholesterol are clinically useful tools, but they are blunt ones — snapshots designed for population screening, not a granular reading of how your biology is ageing in real time. BMI compounds the problem: a 19th-century population statistic that ignores muscle mass, bone density, and the metabolic differences that matter far more after 40. Two people can share the same age on a birth certificate and the same number on a BMI chart while differing by ten years in biological function.

This is where the framing shifts. In Regeneration by Design, Professor Paul Lee positions blood panels not as a disease screen but as monitoring infrastructure — part of the Time pillar, the principle that knowing where your biology stands now is what makes proactive health design possible. Read intelligently, routine blood chemistry can function as an internal MOT: a biological-age readout that reveals direction of travel, not merely whether today's numbers clear a clinical cut-off.

For anyone past 40, the stakes of this shift are practical. Inflammation, glucose regulation, and lipid particle dynamics begin compounding quietly — and the earlier a meaningful baseline is established, the more valuable it becomes when comparisons matter. Which markers, then, actually tell that story?

How composite blood algorithms compute biological age

The car analogy holds here. A vehicle's health is never assessed by the fuel gauge alone — oil pressure, coolant temperature, battery voltage, and exhaust readings combine into a picture no single dial can produce. Biological age works on the same principle.

In 2018, epidemiologist Morgan Levine and her team at the Yale School of Medicine published a landmark paper (PMC5940111, now cited over 4,000 times) introducing DNAm PhenoAge. The algorithm combines nine values that appear on routine blood chemistry panels — albumin, creatinine, glucose, CRP, lymphocyte percentage, mean corpuscular volume (MCV), red cell distribution width, alkaline phosphatase, and white blood cell count — with a person's chronological age to generate a single biological-age score. Crucially, that composite score outperformed every previous epigenetic measure in predicting all-cause mortality, cancer risk, physical functioning, and cognitive decline. No single value in the panel achieves what the pattern across all nine can.

A second generation followed. GrimAge (Horvath et al., 2019) extended the approach by incorporating DNA-methylation surrogates of plasma proteins — notably PAI-1, a clotting regulator, and GDF-15, a stress-response signal — alongside a smoking estimator. Its time-to-death prediction carried a statistical association (Cox P=2.0×10⁻⁷⁵) that ranks among the strongest recorded in ageing science.

Both tools sit firmly in research territory, not on any GP request form. That boundary matters and should be named plainly. What they demonstrate, however, is a principle with immediate practical weight: the nine blood values feeding PhenoAge are already available through a standard private panel. Taken individually, each is unremarkable. Taken together, they describe a direction of travel.

This is precisely what the Time pillar is designed to capture — not a disease threshold, but drift. Monitoring that is built to detect change before change becomes crisis.

The markers worth tracking: a practical panel for the 40+ reader

Six markers form the practical core of what longevity practitioners describe as an internal chemistry audit. Together, they read the body's internal environment — the Chemistry pillar — with a resolution that standard NHS screening does not attempt.

HbA1c measures average blood glucose over roughly three months. The clinical threshold for concern sits at 5.7% (39 mmol/mol), but research-supported wellness targets place the longevity optimum below 5.4% (36 mmol/mol). Even within the so-called normal pre-diabetic range, sustained glycation — the attachment of glucose molecules to tissue proteins — quietly accelerates damage to vessels, nerves, and connective tissue. The number that clears a clinical cut-off is not necessarily the number worth aiming for.

High-sensitivity CRP (hs-CRP) is the primary circulating signal of inflammaging. An optimum below 1.0 mg/L is supported by the evidence; values in the 1–3 mg/L range, frequently reported as unremarkable, still associate with accelerated cardiovascular and cognitive ageing. It is, in practical terms, the easiest real-time measure of how well the immune environment is being managed.

ApoB counts every atherogenic lipoprotein particle directly — including small, dense LDL that standard LDL-cholesterol measurements frequently miss. Mendelian randomisation studies confirm a causal link between ApoB burden and lifespan, making it a more meaningful cardiovascular input than the figure on most standard blood reports.

Lp(a) is genetically determined and needs to be checked only once. Diet and lifestyle cannot meaningfully alter it. Its value is informational: knowing whether inherited cardiovascular vulnerability is present allows for better long-term risk-awareness and, where relevant, clinical conversation. It is data, not a sentence.

Thyroid panel (TSH, free T3, free T4), 25-OH vitamin D, and ferritin round out the picture as systemic status markers. Suboptimal thyroid function, vitamin D insufficiency, and iron dysregulation are disproportionately common after 40 and affect energy, immune competence, and tissue repair capacity — often in ways that do not register as a clinical problem until the deficit is significant.

The NHS Health Check offers basic glucose and total cholesterol as standard. ApoB, fasting insulin, and Lp(a) require private panels — a gap that UK providers such as Medichecks are addressing through home finger-prick kits and nurse-visit options. For anyone using blood monitoring as a design tool rather than a disease screen, that expanded panel is where the useful information lives.

Inflammaging: why low-level inflammation shows up in blood first

Behind every hs-CRP reading sits a mechanism worth understanding — because understanding it changes how you read the number.

The immune system is built to surge. Infection arrives, inflammation mounts, the threat resolves, and the system quietens. What changes with age is that second step. Inflammaging — the term researchers use for a chronic, sterile, low-grade innate-immune overactivation — describes a system that never quite stands down. There is no infection driving it. It accumulates instead as a background hum, measurable in blood long before it announces itself as a named condition.

Its cellular engine is the senescence-associated secretory phenotype, or SASP. Cells that have aged beyond their replicative capacity do not simply go quiet — they continue secreting inflammatory cytokines and proteases, including IL-6 and TNF-α, that gradually shift from broadly immunosuppressive to actively tissue-damaging. CRP and IL-6 are, in practical terms, the downstream readout of this cellular behaviour. When hs-CRP drifts above 1.0 mg/L without obvious cause, it is often SASP-driven low-grade signalling that is registering — not a short-term blip but a systemic condition.

The critical point, and the one the Regeneration by Design framework insists upon, is that this is not a fixed trajectory. A 2024 meta-analysis of randomised controlled trials found that combined exercise training and protein supplementation significantly reduced CRP (P<0.00001) and IL-6 (P=0.001) in older adults — with the combination outperforming either intervention alone. Mediterranean dietary patterns and gut microbiome diversity are further modulators; higher intakes of whole grains, vegetables, and oily fish associate independently with lower CRP and TNF-α concentrations, while gut dysbiosis in ageing is increasingly recognised as an inflammaging driver in its own right.

That is where the Chemistry and Biology pillars converge on the blood panel. What goes into the body — and what lives in the gut — directly shapes what the markers show. It is worth being honest that RCT evidence linking improvements in these inflammatory markers to meaningful extensions in healthspan is still developing; the causal chain is plausible and mechanistically coherent, but not yet settled. What the evidence does confirm is that these numbers move — which means monitoring them is not passive record-keeping but active feedback.

How the four pillars move the needle on your markers

Think of the blood panel as a readout screen — what appears on it reflects the combined output of everything the body is being asked to do. The four pillars are the dials.

Physics — movement and load register quickly in chemistry. A 2023 study of 23,237 generally healthy individuals found a dose-response relationship between running volume and favourable biomarker signatures, including markers of insulin sensitivity and cardiovascular function. Resistance training three times a week is associated with improved HbA1c trajectory and HDL; grip strength — itself a biomarker — rises with consistent loading. The signal is not subtle, and it appears at moderate, accessible volumes, not just elite training levels.

Chemistry — nutrition shapes the same markers through a different mechanism. Dietary glycaemic load has a direct relationship with HbA1c trajectory; protein sufficiency at each meal supports muscle protein synthesis and, as the 2024 RCT meta-analysis showed, combines with exercise to drive down CRP and IL-6 in ways neither achieves alone. ApoB responds to the quality and composition of dietary fats. Mediterranean-pattern eating — whole grains, vegetables, oily fish, nuts — is among the most consistently evidenced nutritional inputs for reducing systemic inflammation.

Biology — sleep, gut, and stress close the loop. Poor sleep elevates fasting glucose and disrupts the inflammatory balance that hs-CRP reflects. Gut microbiome diversity modulates systemic inflammation directly. Chronic psychosocial stress is independently associated with GrimAge acceleration and elevated IL-6 — a finding confirmed in the MIDUS cohort, where higher cumulative social advantage tracked with measurably slower epigenetic ageing.

Time is what turns a panel into intelligence. A single result is a photograph; repeated measurements over months and years reveal direction of travel — whether the biological age gap is narrowing or widening.

The pillars rarely move in isolation. A reader who trains consistently, eats adequate protein, and protects sleep will typically see movement across HbA1c, hs-CRP, and ApoB simultaneously — which is precisely the interdependence Regeneration by Design describes. Blood markers are feedback, not verdict. They are most useful when treated as part of an active, system-level design — and as Professor Paul Lee emphasises, the goal is not to pass a threshold but to understand the direction of travel and act on it.

These markers are tools for personal optimisation, not replacements for clinical advice. If a result concerns you, speak with a healthcare professional.

From a one-off test to a personal biological baseline

A single panel is a starting point. The real value emerges over time — when a second and third result, taken six to twelve months apart, reveal whether the numbers are moving in the right direction or quietly drifting the wrong way. Monitoring is not the same as measuring once.

This is the logic behind Professor Paul Lee's Digital Body Bank concept, set out in Practical Regeneration: capture a comprehensive biological baseline whilst health is strong and stable, and that snapshot becomes the personal reference point against which every future comparison is made. Rather than measuring decline from an average population norm, you are measuring against your own biological best — a fundamentally more useful benchmark for guiding regenerative action.

For UK readers, that baseline is more accessible than it may seem. Private providers including Medichecks offer expanded panels — covering ApoB, fasting insulin, Lp(a), hs-CRP, HbA1c, vitamin D, and thyroid function — via home finger-prick kits or nurse visits, at a price point well below what the NHS Health Check currently includes. Epigenetic clock assessments and proteomic scores in the PhenoAge mould are also commercially available, though they remain at the research frontier and are better understood as future depth than an immediate requirement.

The practical starting point is straightforward: commission a comprehensive panel, map your results against the target ranges covered in this article, and schedule a repeat in six months following any pillar-based change. Regeneration by Design frames this as design thinking applied to biology — systematic, iterative, and grounded in feedback rather than guesswork.

The information here is intended for general wellness and optimisation only, not as a substitute for clinical evaluation. If any result concerns you, discuss it with a qualified healthcare professional.

1. [1] Dose response of running on blood biomarkers of wellness in generally healthy individuals (2023). (2023). https://doi.org/10.1371/journal.pone.0293631 https://doi.org/10.1371/journal.pone.0293631
2. [2] Biological age model using CT-based cardiometabolic biomarkers for longevity (Nature 2025). (2025). https://doi.org/10.1038/s41467-025-56741-w https://doi.org/10.1038/s41467-025-56741-w