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Do You Really Lose Most of Your Heat Through Your Head?

Posted March 23, 2009 12:05 AM by Galina
Pathfinder Tags: body heat old wives' tales urban legends
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This may be the Information Age, but it's amazing how old wives' tales can still keep us in the dark. We like to think we're beyond believing in such outdated myths, but the truth is that many of them are still accepted as fact. The Internet is a great tool for debunking some of the so-called "facts" we were fed as youngsters, but some myths still prevail - even in the warmth and comfort of our "informed" society.

Hold onto Your Hats

Consider the old wives' tale that humans lose most of their body heat through their heads. I'd believed this "fact" since I was a girl, so I was amazed to learn that this is actually incorrect.There is no scientific evidence that more heat escapes from the head than from any other part of the body. Humans lose heat through any exposed skin, and the amount of heat lost depends on the amount of surface area that is exposed.

So what about the speed of this heat loss? Humans do not lose heat more quickly through the scalp than any other part of the body with the same surface area. Therefore, covering one part of the body has the same effect as covering any other part. In fact, only about 10% of body heat escapes through an uncovered head.

Birth of the Myth

So where did this old wives' tale originate? During the 1950s, a military experiment sent soldiers to the Arctic in cold-weather survival suits. Their loss of body heat was measured in the extreme cold, but the survival suits had one important design flaw – they left the participants heads bare. With only their heads left exposed then, the subjects naturally lost most of their heat there.

Over the years, the myth became fact. For example, an Army survival manual from the 1970s claimed that 40 - 45% of body heat is lost through the head.

So now when I go running in the winter, I can wear my ear pops with pride and ignore everyone who says "You're crazy!". But I can also look forward to hearing – again and again - "You're going out in this weather without a hat on?"

Resources:

http://wildernessmedicinenewsletter.wordpress.com/2007/02/14/heat-loss-through-the-head-and-hypothermia/

http://www.guardian.co.uk/science/2008/dec/17/medicalresearch-humanbehaviour

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#1

Re: Do You Really Lose Most of Your Heat Through Your Head?

03/23/2009 5:03 AM

I think this is a missrepresentation of the 'myth' which is based on the assumption that you are fully clothed but with a bare head...
After all if we saw people going out with a big wooly hat but a bare arse we'd helpfully point out that one will loose a lot of heat from the arse.
Del

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#11
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Re: Do You Really Lose Most of Your Heat Through Your Head?

03/24/2009 1:40 AM

I always thought the majority of the heat was lost through the nose and mouth as you exhale. When you inhale, it is at whatever temp (cold usually in canada) and when it comes out it is inriched with watervapour (steam!) and CO2 and 35 or 36 degrees c. Given the high heat capacity of H2O, and the heat needed to change its state, maybe it is true. Perhaps it depends on whether you are resting or not as well.

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#17
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Re: Do You Really Lose Most of Your Heat Through Your Head?

03/24/2009 9:52 AM

Agree.

Also, the body cannot afford to let the head cool down. We have too many important sensors and processors stuck in this apendix... The arms and legs are sacrificed first.

Also, the body fat is not normally concentrated on the head either. Fat is the best insulator that nature uses. Ask the whales...

That being said, I am still convinced that placing a naked man in the cold, the heat loss per surface area will be much higher in the head (including respiration) than anywhere else in most cases. The exact amount depends on the exposure conditions and if the man has hairs and beard.

In extreme cold, you cover everything with a few layers. Even the heat and moisture of your breath is partly recover by the scarf around your face.

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#2

Re: Do You Really Lose Most of Your Heat Through Your Head?

03/23/2009 10:32 AM

When I bundle up to go riding in sub-freezing temperatures, I do just that! Two pairs of pants, a couple of shirts and a vest plus a big coat (coat comes off for the ride), wool socks and insulated boots, hand warmers and gloves...

I hate hats and rarely wear them, but I must admit I'm warmer when I put my helmet on. It's not fleece-lined or anything and doesn't cover my ears, but it keeps that extra 10% in!

But from my experience I've noticed if I keep the big surface areas warm, the rest of me is warm too. For example if I wear my under armor pants under my jeans and a long sleeved shirt under my fleece or jacket, I'm warmer overall because the wind isn't chilling me through.

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#3

Re: Do You Really Lose Most of Your Heat Through Your Head?

03/23/2009 11:52 AM

What if you're bald? Won't you lose more heat through your uncovered head than a person who is not "folically-challenged".

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#4
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Re: Do You Really Lose Most of Your Heat Through Your Head?

03/23/2009 1:07 PM

Obviously, you should just invest in a toupee! It may be pricey, but if you ask me skin-deep beauty is expensive!

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Re: Do You Really Lose Most of Your Heat Through Your Head?

03/23/2009 1:24 PM

"The follically-challenged look on today's men is quite widespread, and aesthetically appealing to the fairer sex."

Obviously, the Urban Dictionary can't be wrong.

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#6
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Re: Do You Really Lose Most of Your Heat Through Your Head?

03/23/2009 1:26 PM

Obviously, that sentence was written by a balding man.

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#7
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Re: Do You Really Lose Most of Your Heat Through Your Head?

03/23/2009 2:03 PM

Yeah, wot of it eh?

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#9
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Re: Do You Really Lose Most of Your Heat Through Your Head?

03/23/2009 11:33 PM

Del, when two bald men put thier heads together, and take a bow, they make an ass of themselves.

Actually there is more exposed skin on the hands. Thats where the most heat will be lost.

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#8

Re: Do You Really Lose Most of Your Heat Through Your Head?

03/23/2009 2:36 PM

Interesting!

I never knew whether to believe this myth or not, although I do love a cute, winter hat. It's amazing to me that the myth has been around since the 1950s and so few people challenge it.

I guess we can now consider this myth "busted". Great job!

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#10

Re: Do You Really Lose Most of Your Heat Through Your Head?

03/24/2009 12:09 AM

Head hold brain uses lots of energy yes?

So with only our head exposed i guess there would be more heat dissipated because the brain produces a lot of heat (in those people who use their brain). At House parties some people faint because they wear a hat (and don't drink enough) causing the brain to overheat, so i guess there is some truth to the myth

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#12

Re: Do You Really Lose Most of Your Heat Through Your Head?

03/24/2009 5:32 AM

I think that there is a bit of truth to the belief that most of one's body heat is lost through the head... if only for the fact that it is the last place one thinks of covering up - where I'm from, that is. On a cold night putting a cap on my head makes a huge difference...

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#13
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Re: Do You Really Lose Most of Your Heat Through Your Head?

03/24/2009 6:45 AM

On a cold night putting a cap on my head makes a huge difference...
Yeah, it's the only sort of knighthood I'm ever going to get

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#14

Re: Do You Really Lose Most of Your Heat Through Your Head?

03/24/2009 7:04 AM

I don't care what the research says I'm warmer with a hat on .Personally I get cold if my neck is exposed or the small of my back. It may not be scientific but each person has a vulnerable spot that personally makes the whole body uncomfortable. For many people it's their feet or hands , for me wearing a hat makes me more tolerant to cold overall particularly a hoody I'm wearing right now.Study's sometimes don't reflect realities.

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#15

Re: Do You Really Lose Most of Your Heat Through Your Head?

03/24/2009 7:40 AM

Wouldn't a simple thermo image of a naked person confirm or deny this?

Of Course I guess you would have to take an image in both the prone and standing position, oh and to be complete one standing on your head. Heat rises after all. So if it just follows this rule. When you stand on your head your feet should be the warmest.

Who has a thermo camera & a model willing to have there picture taken?

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#18
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Re: Do You Really Lose Most of Your Heat Through Your Head?

03/24/2009 10:08 AM

GA Scotch.

Someone in the business of home energy assesment should have such a camera. Or you can rent them. Probably a FLIR camera. Check the Yellow Pages

Finding a model is a lot easier if you have a camera in your hand.

I wonder if digital cams w/ low light capabilities would do the trick. Tape over the IR source and set the camera for low light. I'll expect a full report and software evidence by friday!!

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#22
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Re: Do You Really Lose Most of Your Heat Through Your Head?

03/24/2009 5:07 PM

GA for that Tippy.

As someone who used to swim outdoors 365/year I can confidently say that putting a cap on makes one hell of a difference when swimming in water at about 5ÂșC even though the rest of the body has nothing more than a pair of lycra budgie smugglers to keep warm!

The head does not have the same degree of regulation of the the skin capilliaries as the rest of the body because it cannot aford to get too cold.

Chas

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#16

Re: Do You Really Lose Most of Your Heat Through Your Head?

03/24/2009 8:40 AM

I think the close on eis to upper management the more heat comes out of ones head

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#19

Re: Do You Really Lose Most of Your Heat Through Your Head?

03/24/2009 10:21 AM

Our forearms and legs are radiators for heat.

On a hot day and you want to cool off quickly just rinse your forarms with cool water. You have a lot of veins that run through your arms to serve that purpose.

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Re: Do You Really Lose Most of Your Heat Through Your Head?

03/25/2009 4:09 PM

The classic and reliable cure for fainting: cold water to the inside of the wrists and the back of the neck.

Cooling off, nothing beats drenching your head in a fountain.

As for staying warm, I'd grab a vest first, keep a cool head, and make sure me arse is covered (thanks, Del )

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#20

Re: Do You Really Lose Most of Your Heat Through Your Head?

03/24/2009 2:56 PM

I feel that this is more likely a misunderstanding than an incorrect myth. Since the brain certainly is one of the critical organs for survival, the brain will be one of the last organs that circulating blood will be pumped through. The fingers, toes, feet, hand, arms and legs will have reduced blood flow to keep the brain at a suitable, survivable temperature. So while in sheltered room temperature conditions, the head may or may not dissipate more heat than the rest of the body. I'm certain that without clothing the extremity that a freezing person will loose the most amount of heat will be the head. For other than some parts of the head, the head will still be given warm blood to survive.

So examining heat loss of a dynamic system in one condition can lead to a misunderstanding in other conditions.

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#21

Re: Do You Really Lose Most of Your Heat Through Your Head?

03/24/2009 3:17 PM

I actually learnt that in my high school - ok make that secondary school - health Science [in the English curriculum] class. The explanation was that the brain is so active and therefore performing so much metabolic reactions and consuming so much energy, and thus producing so much heat, all of which is lost through the head, hence the conclusion "most heat is lost in the head".

However, I guess insulating it with a hat decreases the rate of heat loses according to Newtons Law of Cooling, effectively causing the heat to be transported through the blood to the other parts of the body.

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#23

Re: Do You Really Lose Most of Your Heat Through Your Head?

03/24/2009 7:06 PM

Here I thought it was altitude being higher up and all from the rest of your body with greater wind speed.

Generally the the head does not lose any more heat then any other part of the body per square inch. There are times that it does. When you first start to be active the heat loss from the head can be up to 45% of the total lost from the body. This came from the army study. If you have gotten cold enough to shiver it can be up to 55%.

As far as old wives tales go i don't think moms waited until 1950 to tell their kids to put a hat on when going out in the cold. Maybe they use common sense if your going to cover all the other parts of your body to keep from freezing to death why not your head too.

I know I feel more comfortable with my head covered in the cold.

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#24

Re: Do You Really Lose Most of Your Heat Through Your Head?

03/24/2009 11:08 PM

You will die quicker in the cold naked without a hat, than you will naked with a hat.

You will die quicker in the extreme heat naked, without a hat, than you will with a hat.

Rule of thumb, protect your head.

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#25

Re: Do You Really Lose Most of Your Heat Through Your Head?

03/24/2009 11:41 PM

Did anybody read the links? Yes, these are special circumstances, but significant.

The cerebral blood flow does, however, vary based on cardiac output - the harder your heart beats, the greater the blood flow to the brain. And as you increase the blood flow to the brain, you also increase the percentage of heat loss. As it turns out, when you begin to exercise, there is increased cerebral blood flow. This increases the percentage of heat lost through the head to about 50% of total body heat loss. But as the person continues to exercise, the muscles demand more oxygen which increases blood flow. To ensure thermoregulation and maintain normal core temperature (exercises increases body heat), the skin vasodilates which increases blood flow to the skin to cool the blood. The net result is a decrease in the total blood flow to the brain and a decrease in percentage of total body heat lost through the head to about 10%. Once sweating begins, the percent lost through the scalp returns to 7%.

In Gordon's research his test subjects were at rest in cool water, and the researchers were comparing the rate of heat lost by monitoring core temperature through different body parts and quantities of skin exposed. At rest, they found that the rate of heat loss only depended upon the amount of skin surface area exposed, and the percentage of heat lost through the head was the same as the rest of the body.

Research at the Army Research in Environmental Medicine labs showed that there was a temporary increase in heat loss through the scalp that returned to the baseline of 7% as the subjects continued to exercise.

Now, what about hypothermia and heat loss through the head?
If the hypothermia victim is not shivering, they are at rest, and the heat loss through the head remains about 7%. But, this is important, if they are shivering, the percent of heat loss via the scalp can increase to upwards of 55%, so protecting the head well is a very important part of treating the hypothermia patient.

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#26

Re: Do You Really Lose Most of Your Heat Through Your Head?

03/25/2009 4:26 AM

of course!

old-wives' tales, young-wives' tales, whatever, I've always heard about *hot headed*, but not yet of a hot-footed / -handed / -butted man.

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#28

Re: Do You Really Lose Most of Your Heat Through Your Head?

03/25/2009 4:33 PM

Old wives are correct wives as often, or more, than incorrect...so debunking the head heat loss "tale" is bunk itself. The skull is not covered with fat layer as is the rest of body. Instead the brain must rely on bone and sinuses (air spaces) for their insulation properties. Sinuses are not always reliable insulators (especially in winter) since they can be filled/congested with liquid like mucus. Also, the surface-to-area ratio will be a factor in heat loss from the scalp. Consider: Equatorial-/African-race skulls are (evolved) elongated front-to-back, thus favoring heat loss - just like characteristic tall/lean bodies. In contrast, poleward (evolved) races have more spherical/roundish skulls (less surface to volume ratio) in order to lessen heat loss from blood/tissues underlying scalp and skull.

TexEx

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