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(meteorobs) Re: [SHALLOW] IMO says don't drink Hot Drink while Observing in the Cold
AstronomerTed@aol.com wrote:
> The International Meteor Org states on their website
> <http://www.imodot net/visual/major01.html>
> "do not have hot drinks -- they dilute the blood vessels and make you feel
> colder"
>
> This is really true? Everyone that I've ever observed with has always
> advacated "Drink some hot chocolate, or do you want something hot to drink?"
>
> Is this indeed true?
>
> I just can't see drinking a glass of cold chocolate milk in -30 degree
> windchills...... I'd much rather have some hot cocoa...
>
> Let's have some discussion on whats better to drink when observing and if
> this is true or its just an old myth..
>
> ~Ted
There is the possibility that the writer was referring to hot caffeinated
beverages. Caffeine does increase blood pressure and may mediate changes in
certain blood vessels, although its overall effects on vasoconstriction and
vasodilatation remain unclear. (There are many variables involved in such
studies.) See http://www.priory.com/pharmol/caffeine.htm from which I'm
quoting, "This suggests that the methylxanthines have little direct action on
the major resistance vessels. It is more likely that any change in peripheral
vascular resistance results from interplay of the effects on the brain stem and
the heart, with modification or reinforcement by autonomic reflexes, changes in
the concentrations of circulating catecholamines and interaction with
autoregulatory local hormones." The conclusion of one study of the
thermoregulatory effects of caffeine
(http://www.asma.org/abstracts/v69n12/69-1178.html) was that "Ingestion of a
high level (10 mg · kg-1) of caffeine has no effect on skin heat conductance,
sweating, or the rate of increase and final level of rectal temperature during
moderate, submaximal leg exercise."
Cocoa contains theophyline, another mild stimulant.
Dave Mitsky
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