In article ,
Chris Bacon writes:
|
| Under moderately extreme conditions, people have had brain damage from
| wearing protective headgear.
|
| I'd like to see reference material.

Try a literature search (proper cites, not the Web) - it is a known problem.

| and this means that the absence of specific head-cooling causes
| trouble as soon as the average blood temperature approaches the brain's
| limit.
|
| That does not follow. You could have someone exercising very hard indeed
| in a cold environment, and I bet you they would not get heatstroke from
| wearing a hat.

So what? In case heatstroke has damaged your brain, let me remind
you of the context:

In article ,
Chris Bacon writes:
|
| So if you wear an impermeable lagged membrane over that part
| of your head your brain will "overheat"? I don't think so.

You may not think so, but it is nonetheless true.

The protective headgear to which I am referring as causing brain damage
was an approximation to "an impermeable lagged membrane".

| You've strung together a *lot* of wriggly words there. Stick to
| non-extreme gardening, and wear a hat.

The wriggling is all yours, I am afraid.

I never wear a hat, largely because I have a thick natural thatch.
However, many people want/need to, so my initial advice is good:

More importantly, it should be porous to water vapour, as
sweating is the primary mechanism for keeping the brain cool.

Don't wear a plastic bag - wear a cotton, linen, straw or even wool
hat instead.


Regards,
Nick Maclaren.

"Janet Baraclough" wrote in message
...
The message
from "Rupert \(W.Yorkshire\)" contains these words:


"Janet Baraclough" wrote in message
...
The message
from Chris Bacon contains these words:

Nick Maclaren wrote:
White. More importantly, it should be porous to water vapour, as
sweating is the primary mechanism for keeping the brain cool.

But it's not simply perspiration from the scalp that cools
the head, is it. Leaving one ankle, wrist or whatnot(!)
uncovered would do just the same job.

You emit heat faster from the head than anywhere else except the
trunk. That's why premature babies in incubators wear hats, and
rescuers cover the head of someone who has hypothermia.

Janet.

That's only because heat rises.

The insulation afforded by a beard overheats the head to a dangerous
degree, Rupert, as you have probably forgotten by now. This is why
bearded men usually go as bald as coots, as nature tries to compensate.

I thought the idea of holding a new born
babe upside down by the legs was to prevent heat loss:-)
If this theory is correct then cats and dogs do not have a problem on the
basis that they are roughly horizontal.

Cats and dogs mainly sweat through their feet. That's why they aren't
allowed to weat trainers.

Janet

"Puss in boots" being the exception that proves your rule:-)