On Thu, 11 Nov 2004 04:38:35 GMT, Tim Traynor wrote:

The best thing when wave flying is to breath oxygen for a hour before the
flight or going above 8000 ft thus saturating your body with oxygen.

Great flight Mal! I'd love to have a wave flight like that sometime.

However, your body only has a tenuous ability to "store" oxygen, and that is
when it is bound to hemoglobin in your red blood cells. Given that your
cardiac output is about 5 liters/min and your blood volume is about 10
liters you can, theoretically, "saturate" your oxygen stores in about 2
minutes. Furthermore, if you are breathing normally, don't have pulmonary
disease, and are not launching from a significant altitude, your blood is
already leaving your lungs very nearly oxygen saturated. What I am saying is
that it is not nescessary to go on oxygen an hour before a wave flight
because you can't store oxygen or "saturate your body" - do you think being
on 100% oxygen for an hour would allow you to hold your breath significantly
longer?.

As we all know, blood oxygenation levels can change very quickly with the
limiting factors for a healthy pilot being partial pressure of oxygen in the
lung (altitude) and type of breathing (normal full breath vs shallow
breathing vs hyperventilating). This is why a pulse-ox meter can be so
valuable, you may have a false sense of security if you are breathing 100%
O2 but your respiratory rate and depth is slow and shallow resulting in a
surprising hypoxia.

Just stuff to think about. My real pet peave is athletes rushing to the
sideline to get their O2 fix, the trainers or sports docs providing that
must have flunked physiology.

Tim

Tim,
We were taught during an altitude chamber run with the RAAF (Ozzie
Airforce), that breathing 100% Ox for a while before going to a lower
pressure environment reduces the amount of dissolved nitrogen in your
blood, so makes it less likely you will suffer "the bends" at high
altitude.
No mention was made of "being able to store the oxygen for future
use", and I agree with you on this aspect of the discussion.
Maybe some people have heard about the 100% Ox breathing for a half
hour from people who have done a chamber run, but have not understood
the reason for the pre-exposure.
Cheers, John G.