In short
Feeling older than your age is a symptom, and it usually has a findable cause. The common ones are boring and treatable.
- Untreated sleep apnoea, thyroid disease, iron deficiency, low testosterone, depression, alcohol, medication side effects
- Deconditioning, which is reversible and is the single most common answer in people who sit more than eight hours a day
- Silent cardiovascular disease, which does not make you feel old but is worth finding anyway
Biological age tests are not used here to make decisions, because none is validated to change what should be done.
Condition Overview
What do people mean by ageing early?
Usually one or more of four things: energy that will not recover, strength and stamina falling faster than expected, sleep that no longer restores, and thinking that feels slower.
Each of those has a differential diagnosis. Treating them as an inevitable process is the mistake, because most of the common causes are treatable.
What is usually behind it?
| Deconditioning | The most common single answer. About a quarter of adults sit more than eight hours a day and only around a quarter meet activity guidelines. |
| Sleep disorders | Obstructive sleep apnoea and restless legs are common, under diagnosed, and produce exactly this picture. |
| Endocrine | Thyroid disease, low testosterone in men, and the menopausal transition in women. |
| Haematological and nutritional | Iron deficiency with or without anaemia, and vitamin D deficiency. |
| Mood and substances | Depression, alcohol, and the side effects of medicines already being taken. |
Are biological age tests useful?
Not for decisions. They produce a number that feels meaningful, but there is no evidence that acting on that number improves outcomes, and no standardisation between the tests.
The comparison worth knowing: for predicting coronary events, a coronary calcium score outperformed polygenic risk scores in two large population studies. Direct measurement of what has happened in your arteries beats an estimate of what might.
What does track ageing usefully?
- Exercise capacity. The strongest single functional measure, and the one that moves with training
- Blood pressure and LDL, over years. What matters is cumulative exposure, not one reading
- Glucose regulation
- Coronary calcium, over 40. A direct look at accumulated damage rather than a proxy for it
- Kidney function. It declines with age, and regular exercise slows that decline measurably
Why does this matter now rather than later?
Because the largest gains come from the smallest change at the bottom of the range. Moving from inactive to active is worth more than moving from good to excellent, and the earlier that shift happens the more years it acts on.
Greater activity in midlife is associated with fewer chronic conditions in the last five years of life, which is closer to what most people actually want than a longer life with the same illnesses.
When to See a Doctor
- Energy has fallen and rest does not restore it
- Strength, stamina or recovery has dropped noticeably over a year or two
- Sleep is long enough but not refreshing, or your partner reports snoring or pauses in breathing
- Libido, mood, concentration or motivation have changed alongside the physical symptoms
- You have been offered a biological age test and want to know whether it is worth doing
- Unexplained weight loss, night sweats or fever, which need investigation rather than a longevity plan
- Breathlessness or chest discomfort on exertion, or a sudden fall in exercise tolerance
- New confusion, memory loss noticed by others, or persistent low mood with loss of interest
How Dr. Felix Assesses This
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1
Which of the four patterns you have
Energy, physical capacity, sleep, or cognition. They point to different causes, and separating them narrows the list before any test is ordered.
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2
The short diagnostic panel
Full blood count, ferritin, thyroid function, glucose or HbA1c, kidney and liver function, vitamin D, and testosterone in men where the picture fits. Not a long screen, a targeted one.
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3
Sleep, mood, alcohol and medication
Asked about directly, because they are the causes most often missed and the ones least likely to be volunteered.
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4
Cardiovascular risk in parallel
Silent cardiovascular disease does not cause these symptoms, but it is the thing most worth finding in this age group, so risk is calculated at the same visit.
Treatment Options
Healthy Ageing Program
Where should someone sedentary start? Lower than they expect. In a meta analysis of prospective cohorts covering over 135,000 adults,…
View Treatment
Anti-Aging Medical Program
Why is this page sceptical? Because the field has a specific pattern: strong claims, weak evidence, and a business model…
View Treatment
Longevity Consultation
What happens in the appointment? Roughly half of it is history. What you do, how you sleep, how much you…
View Treatment
Why Early Treatment Can Matter
What changes when a cause is found?
Everything about what happens next. Untreated sleep apnoea, low thyroid, iron deficiency and depression all have specific treatments that work, and none of them responds to a longevity programme.
Deconditioning responds to graded activity, and the response is measurable within weeks. That is a much better starting point than an unvalidated number.
What if nothing is found?
That is a useful result too, and it happens often. It moves the plan to the levers with the best evidence: activity, sleep, alcohol, blood pressure, lipids and, if relevant, smoking.
It also means the symptoms are taken at face value rather than explained away, and reviewed rather than dismissed.
What about supplements and anti ageing compounds?
Vitamins, minerals and supplements are rarely tested in randomised trials, because nothing requires them to be. That is not proof they do nothing, but it does mean the confident claims made for them are not backed by the kind of evidence used for medicines.
Deficiencies are worth correcting. Supplementing in the absence of a deficiency mostly is not.
Is it too late if you have let things slide?
No, and this is the most encouraging finding in the area. People who moved from inactive to active had a 22 per cent lower mortality risk, close to those who had been active all along.
Why Early Treatment Can Matter
What changes when a cause is found?
Everything about what happens next. Untreated sleep apnoea, low thyroid, iron deficiency and depression all have specific treatments that work, and none of them responds to a longevity programme.
Deconditioning responds to graded activity, and the response is measurable within weeks. That is a much better starting point than an unvalidated number.
What if nothing is found?
That is a useful result too, and it happens often. It moves the plan to the levers with the best evidence: activity, sleep, alcohol, blood pressure, lipids and, if relevant, smoking.
It also means the symptoms are taken at face value rather than explained away, and reviewed rather than dismissed.
What about supplements and anti ageing compounds?
Vitamins, minerals and supplements are rarely tested in randomised trials, because nothing requires them to be. That is not proof they do nothing, but it does mean the confident claims made for them are not backed by the kind of evidence used for medicines.
Deficiencies are worth correcting. Supplementing in the absence of a deficiency mostly is not.
Is it too late if you have let things slide?
No, and this is the most encouraging finding in the area. People who moved from inactive to active had a 22 per cent lower mortality risk, close to those who had been active all along.
Most causes are treatable
Sleep apnoea, thyroid disease, iron deficiency, low testosterone, depression and deconditioning all have specific treatments that work.
What gets missed
Silent cardiovascular disease causes no symptoms at all, which is why risk is calculated alongside the symptom workup rather than instead of it.
A short targeted panel
A defined set of tests aimed at a named list of causes, rather than a broad screen that mostly produces borderline results.
Cost & Consultation Investment
The consultation and the diagnostic panel are quoted before anything is ordered, and the panel is deliberately short and aimed at a named list of causes. Biological age tests and broad undirected screens are not offered, because there is no evidence that acting on their results improves outcomes. If further tests are needed after the first results, they are discussed and quoted before being arranged.
Frequently Asked Questions
Not as such. It describes how you feel, and the useful work is finding which cause is behind it. In most people it is one of a short list of treatable conditions or simple deconditioning.
They are not used here to guide decisions. There is no standardisation between them and no evidence that acting on the number improves outcomes. Measures like exercise capacity, blood pressure, LDL and, over 40, a calcium score are more useful.
Deconditioning, in most people who ask this question. It is also the one that responds fastest, and the improvement is measurable within weeks.
It can be in men, and it is worth measuring where the picture fits. It is one item on the list rather than the answer, and it is confirmed properly before anything is prescribed.
Sleep, mood, alcohol and medication side effects account for a large share of these cases and are not visible on a routine panel. They are asked about directly rather than inferred.
Correcting a real deficiency helps. Beyond that, supplements are rarely tested in randomised trials at all, so the confident claims made for them are not backed by the same standard of evidence as medicines.
It depends on the cause. Iron and thyroid correction take weeks to months. Deconditioning responds within weeks. Sleep apnoea treatment often produces the fastest and largest change of all.
Evidence
Where this information comes from
Every figure on this page is taken from the sources below. All of them are free to read, so you can check them yourself.
This page is general medical information and does not replace a personal consultation. Trial results are averages across large groups, not a prediction for any one person.