son_of_flubber wrote, On 9/29/2013 4:47 PM:
On Thursday, September 26, 2013 11:49:23 PM UTC-4, Eric Greenwell
wrote:
Since I can keep O2 saturation above 95% at even 18000' using the
normal EDS settings, does that mean I have excellent circulation?
Or really good lung function?


It could also mean that you breathing too rapidly or deeply (mild
hyperventilating). Hyperventilation will dilate your finger blood
vessels and RAISE the pulse oximeter saturation number. And
hyperventilation will simultaneously constrict your cerebral blood
vessels, and thereby LOWER the O2 saturation of the blood going to
your brain (thereby inducing mild hypoxia). Vasodilation may also
lower the temperature of your core and induce the mental dulling
effects of mild hypothermia.

See
http://www.danlj.org/~danlj/Soaring/...-p18-20-22.pdf


It does drop into the 90-95% range sometimes, but that's also when
I realize my breathing is very shallow; i.e., I don't seem to be
inhaling very much after I hear the "poosh" of the EDS oxygen
pulse.

If you're making any conscious effort to "breath", you may be mildly
hyperventilating.

A common way to breath at the correct rate is to talk (or sing) out
loud, this distracts you from thinking about your respiration rate.
The autonomic nervous system works best without conscious or
emotional intervention.

I wonder if there might be a training effect from the "poosh" of the EDS
system, such that a pilot tends to stop inhaling sooner than he
otherwise would.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to
email me)