Does feeling the cold mean I have a thyroid problem?

Not necessarily - some people just feel the cold. But a new, persistent increase in feeling cold, especially with tiredness, weight gain or low mood, is worth a thyroid blood test, because an underactive thyroid is a common and treatable cause.

I have started feeling hot and sweaty and I am losing weight - should I be worried?

It is worth seeing a doctor soon. Heat intolerance, sweating, weight loss and palpitations together can point to an overactive thyroid, which is easily tested for and treatable. Seek emergency care if you also have a very high heart rate with a high fever and confusion.

What is a thyroid storm?

A rare but life-threatening flare-up of a severely overactive thyroid, with features such as a very high fever, a racing heart, and confusion or agitation. It is a medical emergency - call 995 - and is more likely when an overactive thyroid is untreated or poorly controlled.

Are hot flushes just menopause?

Often, yes - hot flushes are common around menopause and perimenopause. But if they come with other changes such as weight loss, a racing heart or a neck swelling, mention it to a doctor, as the thyroid can cause similar heat symptoms and is worth testing for.

Feeling the Cold or Heat More Than Usual: Thyroid and Other Causes

Written & reviewed by the BestDoctors.sg editorial team · Last updated 29 Aug 2026 · General information, not medical advice

Quick answer. Feeling unusually cold when others are comfortable, or unusually hot and sweaty and not tolerating warmth – as a persistent change from your own normal – can point to a treatable cause. The headline is the thyroid: an underactive thyroid classically causes cold intolerance, tiredness and weight gain, while an overactive thyroid causes heat intolerance, sweating, weight loss and palpitations – both diagnosed with a simple blood test. Other causes include anaemia, poor circulation, menopause and some medicines. See a doctor for a persistent change, especially with weight change, palpitations or a neck lump. Call 995 for a very high heart rate with fever and confusion. This is general information, not a diagnosis.

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In a medical emergency, or for severe or sudden symptoms such as breathing difficulty, chest pain, fainting or stroke signs, call 995 immediately.

What the change means

The key idea is a persistent change from your own normal – not a one-off cold office or a hot day. Cold intolerance means feeling cold, or reaching for extra layers, when the people around you are comfortable, and it keeps happening. Heat intolerance means feeling uncomfortably hot, sweating more than usual, or coping badly with warm weather compared with how you used to. On its own, being a “cold person” or a “warm person” is often just normal variation. What earns a look is a genuine change, especially when other symptoms come with it – because that combination is what points towards a testable cause.

The thyroid and other common causes

The thyroid gland sets the body’s metabolic “thermostat,” so it is the headline cause. An underactive thyroid (hypothyroidism) classically causes feeling cold more than usual, tiredness, weight gain, constipation, low mood and dry skin. An overactive thyroid (hyperthyroidism) classically causes heat intolerance, sweating, weight loss despite eating normally, palpitations, tremor, anxiety and poor sleep. Both are treatable, and both are diagnosed with a simple thyroid blood test. Other causes include anaemia or iron deficiency and poor circulation (feeling cold), menopause and perimenopause (hot flushes), low body weight, some medicines, diabetes-related nerve changes, anxiety, and short-lived feverish feelings from an infection.

Causes worth testing for

Thyroid disease in either direction is the key treatable cause behind a persistent temperature change, which is exactly why it is worth a blood test rather than putting up with. A rare but important situation is a thyroid storm – a sudden, life-threatening flare-up of a severely overactive thyroid, more likely when hyperthyroidism is untreated, with features such as a very high fever, a racing or pounding heart, and agitation or confusion. Serious infection or sepsis – feeling very unwell with a high fever, shivering and confusion – also needs urgent care. More usually, a persistent unexplained temperature change alongside other symptoms – weight change, palpitations, a change in bowel habit, mood change, or a neck lump (a goitre) – points towards an endocrine cause worth testing rather than ignoring.

When it is an emergency (call 995)

Call 995 or go to A&E for signs suggesting a thyroid storm – a very high heart rate with a high fever, plus agitation, confusion or feeling extremely unwell, especially in someone known to have an overactive thyroid – or for signs of serious infection or sepsis – a high fever with confusion, feeling very unwell, cold clammy or mottled skin, or a fast heartbeat and breathing. These are uncommon but need immediate assessment. Everyday feeling-cold or feeling-hot is not an emergency; it is the combination with a racing heart, high fever and confusion that changes the picture.

When to see a doctor soon

See a doctor without long delay for a persistent temperature change with weight loss, palpitations, tremor or a neck lump or swelling (a possible overactive thyroid or goitre), or for feeling cold all the time with marked tiredness, weight gain or low mood (a possible underactive thyroid). Any persistent temperature change with feeling generally unwell, or in someone who is pregnant or has another significant health condition, is also worth a prompt check. On a routine basis, a new, persistent change in how you tolerate heat or cold that is not explained by the weather, your environment or a passing illness is a good reason for a simple check-up and, often, a blood test.

What to note and sensible self-care

Keep a short symptom diary: whether it is feeling cold or feeling hot; whether it is new; whether it is constant or comes in episodes (such as flushes); and what else has changed. Note the “thyroid-cluster” symptoms a doctor will ask about – weight change, energy, heart racing or tremor, bowel habit, mood, sleep, periods and any neck swelling. For women with new hot flushes, note the menopause context, and mention any family history of thyroid or autoimmune disease. Sensible basics – dressing for the temperature, staying hydrated, keeping warm or cool safely – are reasonable, but they should not substitute for getting a persistent change checked.

Getting it checked

A doctor will ask about your symptoms, examine your neck, and usually check thyroid function and often iron levels or a blood count with blood tests. In Singapore, a GP or polyclinic is the right first stop and can refer to endocrinology if a thyroid or hormonal cause is likely, or to other specialties depending on the findings. Thyroid conditions are common and treatable, so identifying one is good news rather than bad. This guide does not give any medication or dose – treatment depends entirely on the cause and is decided with your doctor. Patient organisations such as the British Thyroid Foundation offer further information.

The bottom line

Some people simply run cold or warm, but a persistent change from your own normal in how you tolerate cold or heat is worth a check – because the commonest treatable cause, thyroid disease, is easily tested for and manageable. Pay particular attention when the change comes with weight change, palpitations, tiredness, low mood or a neck swelling. Seek emergency care for the rare combination of a very high heart rate, high fever and confusion. Most of the time, a simple blood test provides the answer, and any thyroid or iron problem found can be treated.

Related “when to see a doctor” topics

Sources

NHS – Underactive thyroid (hypothyroidism): nhs.uk
NHS – Overactive thyroid (hyperthyroidism): nhs.uk
NHS – Iron deficiency anaemia: nhs.uk
NHS – Menopause and perimenopause symptoms: nhs.uk
NHS – Tiredness and fatigue: nhs.uk

General information only. This guide helps you decide when a change is worth getting checked – it does not diagnose you or replace advice from a doctor. Most such changes have ordinary causes, but some need assessment, so if a change is persistent, unexplained, or worrying you, see a doctor. Call 995 or go to A&E for any sudden change – sudden face, arm or leg weakness or numbness, sudden trouble speaking, sudden loss of balance or vision, or a sudden severe headache – as these can be signs of a stroke, and act FAST even if the symptoms pass. Also seek emergency care for a severe, rigid or very painful abdomen, or for sudden confusion with fever. This guide does not give medication doses; never start, stop or change prescribed medicine without medical advice.