Healthy ageing: which blood values to monitor from your 40s

Healthy ageing doesn't start with a supplement or a strict diet, but with knowing what quietly shifts under the hood from your 40s onward. Six systems change gradually: your blood vessels, your blood sugar, your hormones, your bones, your inflammation level and your kidneys.

A handful of blood values make those shifts visible, sometimes years before you notice anything.

What strikes me as an advisor: almost every article about ageing gets stuck on tips like "move more" and "sleep better". Fine advice, but you can't measure it. I think you only really get a grip on healthy ageing once you can follow the trends in your own blood instead of guessing at them.

This guide lines up those six systems, ties them to values you can have drawn, and gives you an age table for what can shift in your 40s, 50s and 60s. If you first want to know how old your body reads on the inside, read biological age: what your blood reveals about how old your body really is.

What changes in your body as you get older?

Ageing isn't one process, but many small shifts at once. Your blood vessels stiffen, your insulin sensitivity can drop, hormones like testosterone and oestrogen decline, your bone density slowly falls, your inflammation level creeps up and your kidneys filter a little more slowly. None of these changes announces itself loudly.

Take your blood vessels. Over the years the large arteries stiffen and lose elasticity, a process that gets going well before your first symptom (PMID 12515756). That may partly explain why blood pressure tends to rise on average as people get older.

Your metabolism shifts along with it. Cells often respond a bit less sensitively to insulin, which can let your blood sugar climb slowly without you feeling a thing.

Then the hormones. In men, testosterone often declines gradually from around age 30, by roughly 1 to 2 percent per year. In women, oestrogen changes around menopause, on average near age 51, and that tends to happen more abruptly.

Your bones follow their own rhythm. After 35 bone mass slowly declines, and in women that can speed up around menopause. Osteoporosis develops silently, without pain, until something breaks.

Meanwhile your inflammation level can rise. Researchers call this "inflammaging": a low-grade, chronic inflammation that can increase over the years and that is linked to cardiovascular disease and to frailty later in life (PMID 30065258). You feel little of it, but a sensitive inflammation marker like hs-CRP can pick it up.

And your kidneys? From your 40s they filter a little more slowly on average. The Dutch institute RIVM maps how the population is ageing, and with that ageing, kidney function becomes a value that gets watched more often.

In short, there are six systems you can follow with blood testing:

• heart and vessels (cholesterol, apoB, blood pressure)
• blood sugar (HbA1c)
• inflammation level (hs-CRP)
• bones (vitamin D, calcium)
• hormones (TSH, testosterone, oestrogen)
• kidney function (creatinine, eGFR)

Which blood values are interesting to follow from your 40s?

There's no fixed list that fits everyone, but six values together give a good picture of how your body is ageing. They cover your heart and vessels, your blood sugar, your inflammation level, your bones, your hormones and your kidneys. Below I walk through them system by system, with the numbers included.

Heart and vessels: cholesterol and apoB

Cholesterol says something about the fat travelling through your blood vessels. Alongside the familiar LDL, apoB can be useful, because it counts the number of risk particles rather than only their weight.

Because your arteries stiffen over the years, a baseline reading at 40 can be a handy reference point for later. You'll find the background in prevent cardiovascular disease: which blood values shape your risk.

Blood sugar: HbA1c

HbA1c shows how your blood sugar has behaved on average over the past two to three months. That makes it a calmer signal than a single sugar reading at one moment.

Research in the Framingham Offspring Study and the US NHANES figures showed that HbA1c rises on average with age, even in people without diabetes (PMID 18628569). A slowly rising trend can therefore be partly part of getting older, which is exactly why the trend is more interesting than a single measurement.

Inflammation: hs-CRP

Hs-CRP is a sensitive version of the inflammation marker CRP. Where ordinary CRP mainly picks up spikes from an infection, hs-CRP can also measure the low, smouldering inflammation that can increase over the years.

Take two people aged 52 with a similar lifestyle: one has an hs-CRP of 0.8 mg/l, the other 4.5 mg/l. On paper they both feel fine, but the difference can point to a difference in low-grade inflammation you wouldn't otherwise see. The marker itself is explained on hs-CRP (high-sensitivity CRP).

Bones: vitamin D and calcium

Vitamin D and calcium belong to how your bones are built. The Dutch Health Council (Gezondheidsraad) points out that the skin's production of vitamin D declines with age, and that older adults therefore more often have a lower level, especially in winter.

A blood value doesn't tell you whether you have osteoporosis, a bone density scan does that, but it can give context for how your bones are doing. More on that in prevent osteoporosis: which vitamin D and calcium blood values to test.

Hormones: TSH, testosterone and oestrogen

TSH is the value that says something about your thyroid, the engine behind your metabolism and your energy. It can shift over the years and plays a role in both men and women.

In men, a slowly declining testosterone can fit with getting older. In women, oestrogen changes around menopause. How these hormones connect to energy and sleep sits in staying vital with age: energy, sleep and the blood values you can check.

Kidney function: creatinine and eGFR

Creatinine is a waste product your kidneys normally filter out. From that value and your age, your eGFR is calculated, an estimate of how well your kidneys filter.

In many people the eGFR slowly declines from their 40s, usually without you noticing. That's why it's a value that comes into view more often as you age.

What can you have checked at each age?

Roughly speaking your values shift a little each decade, though it plays out differently for everyone. In your 40s it's often about setting a baseline. In your 50s hormones and bones can change faster. From 60 onward your kidney function and blood pressure watch along more often. The table below lines up the tendencies.

Worth remembering: these are tendencies, not laws. One 60-year-old has the vessels of someone in their 40s, another 40-year-old is already running ahead of their age. That's exactly where the value of measuring instead of assuming sits.

If you want to see which values sit behind each signal, 7 signs of ageing and the blood values behind them is a handy next step.

Can you influence healthy ageing yourself?

To some extent, yes, and that's the encouraging part of this whole story. Lifestyle can influence almost every one of the six systems: movement, food, sleep, smoking and alcohol touch your blood sugar, your fats, your inflammation level and your bones. Blood testing makes visible where your lifestyle lands and where it doesn't.

Take movement. Regular exercise can improve insulin sensitivity, which you can see back in your HbA1c. Strength training can also help preserve muscle mass, something that naturally declines over the years.

That muscle side is often underrated. How muscle mass, strength and the matching values connect sits in staying strong with age: muscle mass, strength training and the blood values involved.

Food and weight can weigh in too. Less alcohol and a steadier eating pattern can go together with more favourable cholesterol and sugar values, though genetics play a role in everyone. What a conscious lifestyle can do in numbers, I work out in healthy old age: lifestyle translated into measurable blood values.

My take: lifestyle advice without measurement is guesswork. Once you place your values before and after a change side by side, "living healthier" becomes a concrete number instead of a good intention. What exactly you adjust, you discuss with your GP.

How often do people have their blood checked?

There's no general answer to that, and I'm not going to prescribe a frequency here. Some people choose to have a baseline measured from their 40s and then keep an eye on it. How often that makes sense for you depends on your situation, your family history and your symptoms, and that's something you discuss with your GP.

What does help is thinking in trends rather than snapshots. A single hs-CRP of 3 mg/l says little, because it can be high due to a cold last week. Two or three readings over a longer period show a pattern.

Measuring preventively isn't a goal in itself. It's a way to see early whether a value is drifting the wrong way, while you still have plenty of room to do something about it with your GP.

If you want to know which tests people often have done together, annual blood test: which tests do you really need gives a level-headed overview.

Where do you start?

Start with a baseline of the six systems, so you have a reference point to set later readings against. Then pick one or two values that fit your story to follow, for example HbA1c if diabetes runs in the family, or vitamin D if you get little time outdoors. Place the result next to your GP.

A measured starting point is worth more than a pile of loose values. It gives you something to fall back on if, five years from now, you want to know whether anything has changed.

If you want those six systems drawn in one go, an extended health checkup can be a logical starting point. If you'd rather choose which values you measure, you build your test via building your own blood test.

My advice stays the same as in the intro: healthy ageing isn't about one miracle number, but about the direction your values are moving. Measure a baseline, follow the trend, and let your GP look along at what you do with it. That's more level-headed than most lifestyle tips, and it's measurable too.

References

1. Ferrucci L, Fabbri E. Inflammageing: chronic inflammation in ageing, cardiovascular disease, and frailty. Nat Rev Cardiol. 2018;15(9):505-522. PMID 30065258.
2. Lakatta EG, Levy D. Arterial and cardiac aging: major shareholders in cardiovascular disease enterprises: Part I: aging arteries: a "set up" for vascular disease. Circulation. 2003;107(1):139-146. PMID 12515756.
3. Pani LN, Korenda L, Meigs JB, et al. Effect of aging on A1C levels in individuals without diabetes: evidence from the Framingham Offspring Study and NHANES 2001-2004. Diabetes Care. 2008;31(10):1991-1996. PMID 18628569.
4. RIVM and Gezondheidsraad (Dutch Health Council). Background information on population ageing and on vitamin D in older age. Available via rivm.nl and gezondheidsraad.nl.

Every blood test result at Vitalcheck includes a professional assessment by a BIG-registered doctor. A blood value is not a diagnosis: always discuss treatment decisions with your GP.