Do you really lose 80% of body heat through your head?

We find out if this saying is true, and whether you should be wearing a hat in cold weather.

Image credit: Shutterstock/encierro

By Rachel Carlyle | Published - 27 Nov 2025 | Updated - 7 Oct 2024

We've all heard it, but do you really lose 80% of body heat through your head?

Your mother’s constant entreaties to wear a hat in cold weather seemed to make a certain sense because, as we all knew, some huge percentage of your body heat escaped through your head, a bit like the steam rising from a rapidly cooling cup of tea. Except that it’s not really true.

This old wives’ tale apparently has its roots in a 1970s US army survival guide, which took the information from military experiments in the 1950s. In those experiments, recruits were wrapped up in Arctic survival suits with only their heads left exposed.

No surprise then, when the scientists discovered that it was their heads that were leaking most of their body heat. There was simply nowhere else it could have come from.

In fact, our heads lose heat at about the same rate as other parts of the body. Researchers discovered this in the early 2000s when they convinced volunteers to plunge into cold water dressed either in a swimsuit or insulated clothing, and with their head either submerged or out.

"They calculated that there was only an 11% increase in heat loss when the head was exposed as well as the body," explains Dr Mark Waldron, physiology lecturer at Swansea University.

Do I still need to wear a hat?

So now we know that only around 10% of body heat is lost through our heads, does that mean we don’t need to bother about a hat in cold weather?

No, says thermal physiology specialist Professor George Havenith at Loughborough University.

"If you are fully dressed and your head is exposed, then you are losing most of the heat from your head, so it makes sense to insulate it."

So even though our head doesn’t lose any more heat than the rest of us, it is more sensitive to changes in temperature. So we actually feel colder with an uncovered head.

Prof Havenith even suspects that the British reluctance to wear a hat may in part explain why mortality rises when the mercury drops.

"If you go to zero degrees you see very little impact on mortality in Scandinavia, where, unlike in the UK, you will see young children in hats even at 10C. I do think there’s a link to mortality rates."

Why? Blood pressure rises when you’re cold (because blood vessels constrict), and in the frail that might be enough to trigger a heart attack or stroke, or so the theory goes.

So your mother was right about that hat after all – just not for the reasons she thought.

Written by: Rachel Carlyle

Over a career spanning 30 years and counting, Rachel Carlyle has written features on news, health, family, education - and everything in between - for national newspapers and magazines. She’s Saga Magazine’s contributing editor and has also ghostwritten two bestselling health and lifestyle books for Penguin.

View author page

An older man laying on the floor holding his knee

Five simple ways to futureproof your knees

Five simple ways to reduce your biological age

How to lose weight without fat jabs - and the fads to avoid

An older couple on a boat in the sunshine

What’s the best age to retire? The pros and cons of retiring in your 50s, 60s and 70s

Are you retiring at the wrong age? The best age to retire for your body, brain, happiness and pocket.

Man with beard in woods holding his neck in pain

Have you got rucksack neck?

If you use a backpack as your everyday bag, here’s how to avoid neck strain – plus the one thing you should never do.

Stylised orange torso with lungs showing spots of inflammation

Pneumonia: what are the symptoms and when should you seek medical treatment?

Everything you need to know about the lung infection, and how you could be ill with “walking” pneumonia without realising it.

An older man doing squat exercises in his home

The surprising link between calf muscles and dementia

Strong calves for a strong mind: how they support our circulation and brain health, with easy moves to strengthen yours at home.

Two couples out walking in the woods looking happy

How to not fall ill this winter

Proven, science-based tips to boost your immunity and avoid seasonal coughs, colds and bugs.

An illustration of a man itching his legs in the bath

Why are my legs so itchy? It’s driving me mad!

Our GP Dr Mark Porter explains what can cause itchy skin, which is a common problem as we get older.

A woman wearing a bag over her head with a grumpy face painted on it

The tell-tale signs you’ve become grumpy

Worried you’ve morphed into Victor Meldrew? Find out how to battle that bad mood, and what to do if you’re stuck with a grouchy loved one.

I tried Nordic bathing and discovered why Finland is the world’s happiest place

The benefits of heat and cold therapy, and how Nordic bathing won over our nervous writer.

Close up of woman in a blue shirt holding her chest with both hands

Am I at risk of heart disease? And the most ignored symptom

Here’s how to spot the symptoms of heat disease and reduce your danger.

Four women laughing and leaning on a wall eating ice creams

7 surprising things that get better with age

Not everything goes downhill as we age – we reveal the things that actually get better as we get older.

Hands placing a plaster on an upper arm with the sleeve rolled up, suggesting a vaccination

Winter vaccine guide: what’s available and what you still can’t get

The NHS winter vaccination campaign kicks off next week. Here’s the lowdown on what you need to book.

A male doctor explaining lumbar anatomy to female patient complaining of back pain at medical clinic | Getty

Back pain: These Pilates exercises could help

Pilates for back pain – what to do if you are suffering, and five gentle exercises that could help.

10 simple ways to reduce dizziness

Dizziness or vertigo: a sensation of spinning, can stop us doing everyday things for fear of falling. Try these tips to stop feeling dizzy

man and woman hiking with walking poles in the mountains

Is it time to retire? The 12 signs that you are truly ready for retirement

Experts outline the tell-tale signs that you are ready for a thriving retirement.

Two smiling older people jumping on a raised trampoline with a swimming pool in the background

Bladder leaks and how to beat them

You don’t have to put up with bladder leaks. We try out the latest pelvic floor gadgets for men and women.

An older man squinting through his glasses at his phone

7 Signs you might have cataracts

Cataracts are a normal part of ageing. Learn how to spot the signs – and when it’s time to consider surgery.

Do you really lose 80% of body heat through your head?

Do I still need to wear a hat?

Written by: Rachel Carlyle

Free £250 M&S gift card with Saga Health Insurance

Related articles