What Blood Tests Show About Your Longevity Risk

Most serious diseases don't announce themselves. Heart disease builds silently over decades. Type 2 diabetes develops for 5–10 years before diagnosis. Thyroid dysfunction creeps in so gradually you attribute the symptoms to ageing or stress. By the time you notice something's wrong, the damage is often well advanced.

But your blood tells the story much earlier. The right biomarkers can reveal cardiovascular risk, metabolic dysfunction, hormonal decline, and nutritional deficiency years before symptoms appear — when prevention is most effective and intervention is simplest.

Prevention Beats Cure — But Only If You Test

The NHS Health Check programme offers a basic cardiovascular risk assessment every 5 years for adults aged 40–74. It checks total cholesterol, blood pressure, and blood sugar — the bare essentials. It doesn't include advanced cardiovascular markers like ApoB or Lp(a), doesn't assess hormonal health, and doesn't screen for the nutritional deficiencies that underpin many chronic conditions.

According to the British Heart Foundation, cardiovascular disease remains the UK's second leading cause of death, claiming around 170,000 lives annually. Many of these deaths are preventable — but prevention requires knowing your risk before the first event.

Practical takeaway: An NHS Health Check is better than nothing, but it's a screening tool, not a comprehensive assessment. For genuine prevention, you need a broader panel of biomarkers tested more frequently.

The Five Pillars of Longevity Testing

Longevity blood testing covers five interconnected systems. Weakness in any one pillar can undermine the others:

• Cardiovascular health — heart, arteries, and lipid metabolism
• Metabolic health — glucose processing, insulin, and energy
• Thyroid function — metabolic rate, energy, and repair
• Hormonal health — strength, mood, and resilience
• Nutritional status — the building blocks for optimal function

Cardiovascular Markers: Beyond Basic Cholesterol

A standard NHS lipid panel measures total cholesterol, HDL, LDL (calculated), and triglycerides. This is useful but incomplete. The markers that truly predict cardiovascular events are more nuanced.

• ApoB (apolipoprotein B) — counts the total number of atherogenic (artery-damaging) particles in your blood. The 2021 ESC guidelines recognise ApoB as a superior predictor of cardiovascular risk compared to LDL cholesterol. Optimal is below 0.8 g/L for moderate risk; below 0.65 g/L for high risk
• Lp(a) (lipoprotein-a) — a genetically determined risk factor that affects roughly 20% of the population. You only need to test it once since it barely changes over your lifetime. Above 75 nmol/L significantly increases risk, and standard cholesterol-lowering drugs don't reduce it
• hsCRP (high-sensitivity C-reactive protein) — a marker of systemic inflammation. Chronic low-grade inflammation drives atherosclerosis independently of cholesterol levels. Below 1.0 mg/L is optimal; above 3.0 mg/L indicates elevated cardiovascular risk
• Triglycerides — elevated triglycerides (above 1.7 mmol/L) signal metabolic dysfunction and are an independent cardiovascular risk factor

Practical takeaway: If the only lipid marker you've ever had tested is total cholesterol, you're looking at a blurry photograph. ApoB, Lp(a), and hsCRP complete the picture.

Metabolic Health: The Silent Epidemic

Metabolic dysfunction is arguably the greatest health threat in the UK today. An estimated 1 in 3 adults has pre-diabetes — and most don't know it. The standard NHS fasting glucose test only catches the problem once it's fairly advanced.

The markers that reveal metabolic health earlier include:

• HbA1c — your average blood sugar over 2–3 months. Below 42 mmol/mol (6.0%) is non-diabetic. Between 42–47 mmol/mol is pre-diabetic — the window where lifestyle intervention is most powerful
• Fasting insulin — perhaps the most underused biomarker in standard medicine. Insulin rises years before blood sugar does, making it an earlier warning signal than glucose or HbA1c. Optimal fasting insulin is below 60 pmol/L
• Fasting glucose — useful alongside the above. Normal is below 5.5 mmol/L
• HOMA-IR — a calculated index of insulin resistance derived from fasting glucose and insulin. Below 1.0 is ideal; above 2.0 suggests meaningful insulin resistance

The combination of HbA1c and fasting insulin catches metabolic problems 5–10 years earlier than glucose alone. This is critical because pre-diabetes is reversible with lifestyle changes — but type 2 diabetes, once established, is much harder to manage.

Practical takeaway: Even if your fasting glucose has always been "normal," ask for HbA1c and fasting insulin. The combination reveals metabolic dysfunction long before a diabetes diagnosis.

Thyroid Function: The Master Regulator

Your thyroid controls metabolic rate, energy production, body temperature, and tissue repair. Thyroid dysfunction affects roughly 1 in 20 people in the UK, with women affected five to eight times more often than men. Yet it's frequently missed because standard screening typically only measures TSH.

A comprehensive thyroid panel includes:

• TSH — the pituitary signal telling the thyroid how hard to work. Normal is 0.4–4.0 mIU/L, but many functional medicine practitioners consider 0.5–2.5 mIU/L optimal
• Free T4 — the main circulating thyroid hormone. Normal is approximately 12–22 pmol/L
• Free T3 — the active thyroid hormone that your cells actually use. Normal is approximately 3.1–6.8 pmol/L. Some people convert T4 to T3 poorly, and this only shows up if you test both
• Thyroid antibodies (TPO, TG) — detect autoimmune thyroid disease (Hashimoto's), often present years before TSH becomes abnormal

Practical takeaway: A TSH test alone is a screening tool. If you have symptoms — fatigue, weight gain, cold intolerance, brain fog, hair loss — insist on a full thyroid panel including Free T4, Free T3, and thyroid antibodies.

Hormones: The Decline You Can Measure

Hormonal health underpins energy, mood, body composition, and cognitive function. Both men and women experience gradual hormonal changes from their thirties onwards — and these changes are measurable long before they become clinically obvious.

For men:

• Testosterone (total and free) — below 12 nmol/L suggests deficiency. SHBG affects how much testosterone is bioavailable
• DHEA-S — declines steadily with age; low levels are linked to fatigue and reduced immunity

For women:

• Oestradiol — fluctuations and decline drive perimenopausal symptoms
• FSH — rising FSH is one of the earliest markers of approaching menopause
• Progesterone — declining progesterone causes anxiety, insomnia, and irregular cycles years before full menopause

Both sexes:

• Cortisol — chronic elevation from prolonged stress suppresses immune function and accelerates ageing
• SHBG — high SHBG reduces bioavailable testosterone and oestradiol, even when total levels appear normal

Practical takeaway: Testing gives you a baseline and tracks change over time, informing decisions about lifestyle, supplementation, or hormone therapy.

Vitamins and Minerals: The Foundation

Nutritional deficiencies are remarkably common in the UK, even among people who eat well. They're also one of the most easily correctable causes of fatigue, poor immunity, mood disturbance, and impaired recovery.

Key markers include:

• Vitamin D — deficient in an estimated 40% of the UK population during winter months. Optimal is above 75 nmol/L. Below 25 nmol/L is clinically deficient
• Vitamin B12 — essential for neurological function and red blood cell production. Below 200 ng/L is deficient; many practitioners target above 500 ng/L
• Folate — works alongside B12. Deficiency causes anaemia and impairs DNA repair
• Ferritin — your iron store. Below 30 µg/L suggests depletion even if haemoglobin is normal. For optimal energy, many clinicians target above 70 µg/L
• Magnesium — involved in 300+ enzymatic reactions. Deficiency causes cramps, poor sleep, anxiety, and fatigue

Practical takeaway: These are cheap to test and cheap to fix. There's no reason to walk around deficient in vitamin D or B12 when a simple blood test and targeted supplementation can make a measurable difference to how you feel.

When to Start Testing

The simple answer: earlier than you think. Here's a sensible framework:

• 20s: Baseline blood test to establish your personal reference ranges. This is particularly valuable because population "normal" ranges are broad — knowing your own baseline is far more informative
• 30s: Begin annual or biannual testing. Metabolic and hormonal changes start earlier than most people realise
• 40s: Comprehensive annual testing becomes essential. This is when cardiovascular risk, metabolic dysfunction, and hormonal decline accelerate
• 50s and beyond: Continue annual testing with particular attention to cardiovascular, metabolic, and hormonal markers

The NHS Health Check starts at 40, every 5 years. That's a 5-year gap in which significant changes can develop undetected. Annual testing closes that gap.

Essential vs Complete: Which Is Right for You?

If you're new to longevity blood testing, start with a panel that covers the five pillars: cardiovascular, metabolic, thyroid, key hormones, and core vitamins. This gives you a broad overview and identifies any areas of concern.

If you have a family history of heart disease, diabetes, thyroid problems, or hormone-related conditions — or if an initial panel reveals borderline results — a more comprehensive panel adds advanced markers like ApoB, Lp(a), fasting insulin, full thyroid antibodies, and a wider nutritional assessment.

Practical takeaway: You don't need to test everything every time. Start broad, identify your personal risk areas, then focus subsequent testing on the markers that matter most for your individual health profile.

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