Cold hands and feet: 8 causes and what your blood says about them

Cold hands and feet usually come from a completely normal reaction: when it gets cold, the small blood vessels in your fingers and toes narrow so your core stays warm. In some people something else plays a part, such as low ferritin, an underactive thyroid or reduced circulation. Below are 8 causes, each with the blood value that may say something about it.

What strikes me about this complaint is that almost nobody reports it. Being cold feels like a nuisance, not like something you book an appointment for.

Yet it's sometimes the first visible sign of something you can simply measure. That makes it worth looking past a thicker pair of socks.

The 8 causes in short

Most causes fall into four groups: too little oxygen transport (iron, anaemia), a lower metabolic rate (thyroid), a problem with the blood vessels themselves (Raynaud's, narrowing, smoking) and nerve damage (vitamin B12, high blood sugar). Your build matters too. Here's the full list.

1. Iron deficiency, even without anaemia
2. An underactive thyroid
3. Raynaud's phenomenon
4. Reduced circulation in your arteries
5. A vitamin B12 deficiency
6. High blood sugar and nerve damage
7. Smoking and nicotine
8. Low muscle mass, low body weight or low blood pressure

1. Iron deficiency, even without anaemia

Iron sits inside haemoglobin, the protein that carries oxygen through your blood. With too little iron, your hands and feet receive less oxygen, and that can feel like cold. Ferritin reflects your iron stores, and it can already be low while your haemoglobin still looks fine.

That last part is the piece that often gets missed. For fatigue, a GP often checks Hb first, and if that's normal the workup can look finished. A 2021 paper in Clinical Medicine calls iron deficiency without anaemia a diagnosis that matters, in those words.

Low iron stores are more common in women who still menstruate. Athletes and people who eat little meat also sit low more often.

The value that can say something here is ferritin, usually alongside haemoglobin and transferrin. More on this pattern in our piece on anaemia and iron deficiency.

2. An underactive thyroid

Your thyroid helps set how fast your body burns energy. When it slows down, heat production drops, and many people notice it in their hands and feet first. Feeling cold is one of the classic complaints in hypothyroidism, together with fatigue, dry skin and a general slowing down.

It's rarely cold alone. Other things usually join in: your hair gets drier, your thinking slows, you gain a little weight without eating differently.

A 2024 Lancet review described the symptoms of an underactive thyroid as broad and not very specific, which is exactly why people live with it for so long.

The values that offer insight are TSH and free T4. We covered this in more depth in thyroid symptoms, values and which blood test gives insight.

3. Raynaud's phenomenon

In Raynaud's, the small arteries in your fingers and toes overreact to cold or stress. They clamp shut briefly. Classically the finger turns white first, then blue, then red as it warms up, often with tingling.

This is a reaction of the blood vessels themselves, not of your blood. So a blood test doesn't demonstrate Raynaud's.

Where blood work can help is telling apart the common form without an underlying condition from the rarer form that accompanies an autoimmune disease. A 2019 review describes that distinction as the core of the assessment.

Recognise that sharp colour change? Mention it to your GP, because it's a pattern a doctor wants described.

4. Reduced circulation in your arteries

When the arteries to your legs narrow, less warm blood reaches your feet. That's called peripheral arterial disease. Alongside cold feet it often causes calf pain when walking that eases again when you stand still.

This is the cause I'd personally watch most closely, because it connects most directly to your heart and vessels. A 2015 review in Circulation Research reports that the condition is common worldwide and often stays unnoticed for a long time.

Smoking, diabetes, high blood pressure and an unfavourable cholesterol profile all raise the risk. The Dutch Heart Foundation counts cold feet with pain on walking among the signals worth taking seriously.

Blood tests don't measure the narrowing directly, but cholesterol, glucose and HbA1c do sketch your risk profile. How that narrowing develops is explained in narrowed blood vessels.

5. A vitamin B12 deficiency

Vitamin B12 helps keep the protective sheath around your nerves intact. With a longer standing deficiency, the nerves in your hands and feet can work less well. That more often gives tingling, numbness, or a cold sensation that doesn't match the temperature around you.

The difference from real cold is subtle but useful: with nerve complaints your hand feels cold to you, while it feels perfectly warm to someone else.

People who eat few animal products, older adults, and people on long term acid reducers or metformin more often have a low value.

The value that speaks to this is vitamin B12, sometimes with active B12 added. See also our overview of vitamin deficiency and which vitamins to test.

6. High blood sugar and nerve damage

A blood sugar that stays raised for a long time can damage the smallest blood vessels and nerves, and those sit precisely in your feet. The result is often a combination: cold feet, tingling, and less sense of what you're standing on. In diabetes that's a familiar pattern.

What makes it tricky is how quietly it happens. You notice it once the nerves have already been working poorly for a while.

The values that offer insight are fasting glucose and HbA1c, which reflects your average blood sugar over roughly three months. If you notice changes in sensation in your feet, always have your GP assess them.

7. Smoking and nicotine

Nicotine narrows your blood vessels shortly after use. With daily smoking that adds up, and over the longer term smoking damages the vessel wall itself. So in smokers, cold hands and feet are more often structural than coincidental.

This is the only cause on this list where the effect is directly measurable at your fingers. Measure your skin temperature before and twenty minutes after a cigarette, and you'll see the difference.

Blood tests don't show the effect of smoking as a single value. Cholesterol and inflammatory markers such as CRP do shift in an unfavourable direction more often in smokers.

8. Low muscle mass, low body weight or low blood pressure

Muscle produces heat, even when you sit still. Anyone with little muscle mass or a low body weight simply makes less heat and loses it faster too. With low blood pressure there's also slightly less push behind the blood flow to your fingers and toes.

This is the most harmless cause of the eight, and probably the most common one. It explains why a slim 28 year old woman is cold at the office while her colleague opens a window.

There's no blood value that demonstrates this. It's mostly the answer left over when the rest shows nothing.

Three questions that narrow the pattern

Eight causes is a lot to start from. In practice, three questions move you fairly quickly towards a smaller group. They don't replace an assessment by a doctor, but they do help you decide what you're looking at and what to raise.

Question 1: are your hands cold in a warm room too? Everyone gets cold on a winter morning. If your fingers stay cold at 21 degrees indoors, that points more towards your metabolism or your iron stores than towards the temperature.

Question 2: do your fingers change colour with a sharp edge? In Raynaud's you see a clear border: one part of the finger is white, the rest simply pink. A gradually pale hand is something different from a finger that looks half white as if a line had been drawn.

Question 3: has anything else joined in over recent months? Cold on its own says little. Cold plus fatigue, cold plus hair thinning, or cold plus tingling makes the story a good deal more specific, and those are exactly the combinations that show up in blood.

An example of how that plays out. Say you're 34, you've been colder than you used to be for two winters, your hair sits thinner in the brush and you're falling over by nine in the evening. That pattern points towards your thyroid and your iron stores rather than your blood vessels, and that saves a lot of guesswork before you have anything drawn.

Answered no to all three, and been the cold one your whole life? Then cause 8 is probably the whole story.

Which blood values offer insight here?

There's no blood test for cold hands and feet. What you can do is look separately at the causes that do show up in blood. This table sets out which value belongs to which possible cause, and what that value actually measures.

A value inside the reference range doesn't rule a complaint out, and a value outside it doesn't automatically explain one. Your GP can help you work out what a result means in your situation.

When do you call a doctor instead of getting blood drawn?

Sometimes a blood test isn't the first step. Call your GP if a foot or hand suddenly turns cold, white or blue and feels painful, if a wound on your foot won't heal, or if you get calf pain when walking that disappears when you stand still.

Those are complaints someone wants to look at, not measure. Don't wait for a test result first.

Thuisarts, the Dutch GP information service, describes cold hands and feet on their own as usually harmless, and that's true. It's the combination with other signals that matters.

Why am I always cold when others are warm?

Being structurally colder than the people around you often comes from a mix of build and metabolism: less muscle mass, a lower weight, and sometimes a thyroid working slightly slower. In women, skin blood flow also responds more strongly to temperature changes.

When it's new, that's more interesting than when it has always been the case. If you've been the cold one your whole life, it probably just belongs to you.

If it changed over recent months, and fatigue or breathlessness came with it, that's the moment to do something with it.

Cold hands and fatigue often turn up together

That's no coincidence. Iron deficiency and an underactive thyroid both cause cold sensitivity and tiredness, by different routes. A 2025 JAMA review describes iron deficiency in adults as common and regularly missed, precisely because the symptoms are so general.

That's exactly where the trap sits. You put tiredness down to work and cold down to the season, and a measurable cause stays under the radar for years.

Recognise that combination? Then also look at causes of fatigue and the blood values that offer insight.

Getting your own values measured

If you want to know where you stand on the measurable causes, in practice there are three: your iron stores, your thyroid and your vitamin B12. You can have those drawn separately with a ferritin test, a TSH test or a vitamin B12 test, without a referral.

My advice would be this: don't start with everything at once. Take the value that fits what else you notice, then discuss the result with your GP.

Sources

• Iron Deficiency in Adults: A Review. JAMA, 2025. PMID 40159291
• Iron deficiency without anaemia: a diagnosis that matters. Clinical Medicine (London), 2021. PMID 33762368
• Iron deficiency anaemia. The Lancet, 2016. PMID 26314490
• Hypothyroidism. The Lancet, 2024. PMID 39368843
• Raynaud's phenomenon. Journal of Scleroderma and Related Disorders, 2019. PMID 35382391
• Epidemiology of peripheral artery disease. Circulation Research, 2015. PMID 25908725

Every blood test result includes a professional assessment from a BIG-registered doctor. For treatment decisions, discuss your results with your GP.