Nick Maclaren wrote:
Chris Bacon writes:
| The human brain is such a heat source, and so sensitive
| to overheating, that there is a lot of specialist blood flow to the
| scalp and even through the skull. You remark applies to the rest of
| the body, but only partially to the head.
|
| 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.

Under moderately extreme conditions, people have had brain damage from
wearing protective headgear.

I'd like to see reference material.

The point is that the rest of the body can
take higher temperatures than the brain (in the case of muscle, MUCH
higher)

Yes, of course...

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.


People exercising hard in hot conditions may have limb blood
temperatures higher than the brain can take.

True enough. It does not mean that their brain will overheat, though.


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