On 6 Nov 2004 19:20:43 -0800, (PaulH) wrote:

I took my Arrow up to 10,500 today to check out my fingertip O2
measuring device. I can maintain 90-93% saturation with deep
breathing and no supplemental O2. Anybody know what the minimum safe
level is for daytime? I guess it might be cumulative, i.e. the longer
you go at 92% the less safe it is? Dropped down to about 88% when I
got distracted with some cockpit chores and started normal sea level
breathing.

It varies from individual to individual, and even from day to day.

SaO2 of greater than 90% is said to be safe for most. And hypoxia effects
are cumulative.

Folk who live at high altitudes can tolerate less because of certain
physiologic adaptations that take place.

USAF recommends (or at least did when I was in) oxygen at 10,000 ft and
higher.

Also, even at 6000 ft or so, night vision will start to go. Some clear
night, go up to 6000 ft and fly for 1/2 hour or so -- then put on oxygen
and watch the stars come out!




Ron (EPM) (N5843Q, Mooney M20E) (CP, ASEL, ASES, IA)