Your biological age is an estimate of how old your body functions, apart from your calendar age. Two women of fifty can differ biologically by years. One smokes and moves little, the other trains and sleeps well, and you see that difference in their bodies.
The idea is popular, and there are now dozens of online "age tests". Some measure something meaningful, many do not. I think it matters to make that difference clear, because a low score from a free test says little if there is nothing reliable behind it.
In this article you will read what biological age is, how you measure it, and which measures research really links to ageing.
What is biological age?
Biological age describes how old your body is based on how it works, not on your birth year. Where your calendar age goes up by one each year, your biological age can run faster or slower. Lifestyle, muscle strength and metabolism play a part.
The difference is sometimes large. Someone of sixty with plenty of muscle mass, a healthy weight and good fitness can be biologically younger than their peers. Conversely, chronic stress, smoking or little movement can speed up the process.
For women, menopause plays into this too. The drop in oestrogen changes your bones, blood vessels and muscles, and can speed up ageing on some fronts.
How do you measure your biological age?
There is no single test that measures your biological age perfectly. Scientists mainly use a combination of functional measures and patterns in your DNA. A single value from an online quiz is no replacement for that.
The most researched method is the so-called epigenetic clock. It looks at chemical markings on your DNA, methyl groups, that change with ageing. The first version predicted calendar age strikingly accurately across many tissues (Horvath, 2013).
Later clocks went further. The DNAm PhenoAge clock combines methylation with clinical values and predicts not only age, but also health risks (Levine et al., 2018). These clocks are powerful, but mainly research tools, not something you do at home.
Which measures really link to ageing?
Besides DNA clocks, there are simple functional tests that predict surprisingly well how your older years go. Walking speed and muscle strength are among them. They do not measure your exact age, but they do measure your resilience.
Walking speed is a nice example. In an analysis of nearly 35,000 older adults, a higher walking speed was linked to longer survival (Studenski et al., 2011). The faster someone walked, the greater the chance of more healthy years.
The table below sets a few commonly used measures side by side, with what they do and do not tell you.
| Measure | What it roughly says |
|---|---|
| Epigenetic clock | ageing at DNA level, mainly research |
| Walking speed | resilience and survival at older age |
| Hand grip strength | overall muscle strength and risk of complaints |
| Fitness (VO2max) | heart and lung capacity |
| Online "age test" | usually an estimate from questions, not validated |
What stands out: the most reliable measures are not mysterious scans, but simple things like how fast you walk and how strong you are. And you can influence those yourself.
Can you determine your biological age with a blood test?
Not precisely. A single blood value is not a validated biological clock. But some values do give insight into processes linked to ageing, such as blood sugar, cholesterol and inflammation.
Think of a high fasting glucose that points towards insulin resistance, or a raised cholesterol linked to vascular ageing. These values are not an age meter, but they do sketch where your body is under pressure.
At Lunara you can get a broad view with an extended health check, assessed by a BIG-registered doctor. See the result as a snapshot, not as a verdict on your biological age.
How do you lower your biological age?
You cannot stop ageing, but the pace is partly influenceable. The biggest levers are the same as for healthy ageing: moving, building strength, eating well and not smoking. The Dutch health institute RIVM tracks the healthy life expectancy of the population, and it is strongly linked to lifestyle.
Strength is an underrated factor here. Because muscle strength links so well to resilience, preserving muscle mass is one of the most concrete things you can do. How to approach that is in preserving muscle after 50.
Want to know where you stand now in numbers? Then a baseline can help. In preventive blood testing for women you read when that is worthwhile. And for the broader picture there is our overview on healthy ageing for women.
What do you do with this knowledge?
Do not be fooled by a free online test that gives you a "body age" of 38 or 62. Better to look at the things you can steer yourself: movement, strength, sleep and food.
Want a more objective starting point? Discuss with your GP whether measuring a few basic values fits your situation. That gives you something concrete to steer by, instead of a number without support.
Sources
- Horvath S. DNA methylation age of human tissues and cell types. Genome Biol. 2013;14(10):R115. PMID 24138928.
- Levine ME, Lu AT, Quach A, et al. An epigenetic biomarker of aging for lifespan and healthspan. Aging (Albany NY). 2018;10(4):573-591. PMID 29676998.
- Studenski S, Perera S, Patel K, et al. Gait speed and survival in older adults. JAMA. 2011;305(1):50-58. PMID 21205966.
- RIVM. Healthy life expectancy. Available via rivm.nl.
Every blood test result at Lunara includes a professional assessment by a BIG-registered doctor. For treatment decisions, discuss your results with your GP.
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