Re: [Paddlewise] Mono Lake

You must have missed the mea culpa where I corrected my self and posted some
facts.  I am not going on memory any more but above 12,000 exercise gets
pretty hard I think.

Anyhow, see below:
My response was way off base vs. the oxygen content at altitude.  Thanks to
an alert response from a reader of this list.
Mono Lake is 6384.9 ft above sea level

Oxygen situation is as follows I hope:

Humans can survive for weeks without food; days without water; however, we
can only survive for minutes without oxygen. While the percentage of oxygen
in the atmosphere remains fairly constant up to 70,000 feet, the available
amount of oxygen to sustain mental and physical alertness decreases above
10,000 feet. The atmosphere is primarily nitrogen (78%) with oxygen
comprising 20.9 percent of the atmosphere.

The atmosphere is generally considered to exist up to 100 miles (1,200 miles
technically) and above this altitude the atmosphere is virtually a vacuum
until reaching outer space. One-half of the atmosphere is contained from
18,000 feet to the earth's surface (the other 50 percent is above 18,000
feet). At sea level, the pressure of the atmosphere is 14.7 pounds per
square inch (PSI). At 18,000 feet the pressure is 7.34 PSI.  By 34,000 feet,
the pressure is reduced to one-half of the 18,000 foot level to 3.62 PSI. It
is this reduction in pressure (or in other words, the less dense air) that
causes hypoxia.

Hypoxia is the effects of an insufficient supply of oxygen to the body.
Every person can have different symptoms when suffering from hypoxia (U.S.
Air Force aircrews are required to take an altitude chamber ride every three
years to reinforce and identify their hypoxic symptoms). Some of the common
symptoms are: lightheaded sensation, dizziness, reduced vision, and
euphoria.

The early signs of hypoxia generally begin at 10,000 feet. U.S. Air Force
aircrews must use supplemental oxygen when the cabin pressure of the
aircraft reaches this altitude. (NOTE: The cabin altitude of an airliner and
other transport aircraft by design will climb no higher than 8,000 feet.)
Without supplemental oxygen, your blood has about 90% of its normal oxygen
level at 10,000 feet.

--
=^..^=
--Mel--
Mel Lammers
mslammers_at_earthlink.net


----- Original Message -----
From: M. Wagenbach <wagen_at_u.washington.edu>
To: <PaddleWise_at_lists.intelenet.net>
Sent: Thursday, September 02, 1999 1:51 PM
Subject: Re: [Paddlewise] Mono Lake


> > 6. Remember that 80% of the oxygen is in the first 3000 ft of altitude.
> > Mono is above that.
>
> Whoa! Alert!!  You may want to recheck your source on that.  Maybe that
should
> be 30 Thousand feet.
>
> I'm from Denver, and not everyone there is DEAD!!  I can attest that even
at
> 14,000 feet, it is possible, though a tad painful, to bicycle uphill at at
> least 50% of the rate one can climb at sea level.
>
> Mike Wagenbach
>
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