FL200? Or does it have to be higher.
It depends on your individual resistance to hypoxia, the ascent regimen and the departure altitude. Mt. Everest (29029 ft AMSL) has been climbed without oxygen. The town of La Rinconada in Peru is at 16728 ft AMSL.
I suppose brain damage might occur as a result of the hypoxia induced loss of consciousness and subsequent crash coming all the way down from FL 200 :-)
For most teenagers, sea level. :)
Mt. Everest (29029 ft AMSL) has been climbed without oxygen. The town of La Rinconada in Peru is at 16728 ft AMSL.
OK, but those were super-fit people, and people who are genetically used to it.
I suppose brain damage might occur as a result of the hypoxia induced loss of consciousness and subsequent crash coming all the way down from FL 200 :-)
Well, I have met a guy who went to FL180, no oxygen, and woke up in a forest on the side of a mountain. Europe, a homebuilt, but I am not saying any more because I don’t know if it was ever published.
Would FL200 do permanent brain damage, eventually? I am surprised there is no data on this.
Yes, I imagine it would. There will be data, but it’s likely to state the critical figures as oxygen saturations rather than flight levels – if for no reason than you or I may boast very different O2 saturations at FL200.
There are plenty of people out there who, for one reason or another, have lungs that don’t work very well and who run at low oxygen saturations. Walk around any hospital and there are people with oxygen saturations at sea level in the high 80s who live their entire lives like that. The most common disease would probably be chronic obstructive pulmonary disease – the problem being that if you give people with COPD too much oxygen, it stops some of them from breathing, so you have to find some sort of balance.
I’ve always been told that 89% is the lower limit of acceptable, because of the risk of chronic hypoxic brain damage. Reading around just now I’ve seen limiting O2 partial pressures of 50mm Hg (6.6kPA) which would correspond to about 80% on a saturation monitor. It might also be that we are told to use the higher figure because saturation monitors tend not to be reliable at readings much below this, so if you keep at 89% you can be reasonably sure you’re safe, but if you have a reading of 80% you can’t really be sure that the patient isn’t running at 70%
In practical terms it’s not going to be easy to do a relible experiment to look at this question, but if you google ‘chronic hypoxia brain injury irreversible’ there is a fair amount out there.
Peter wrote:
OK, but those were super-fit people, and people who are genetically used to it.
You just have to adapt to it. Some years ago 10-20? the Norwegian skiing team used to stay in “high level houses”. Hhouses with decreased level of oxygen (more nitrogen). The idea is to let the body adapt over time to produce more red blood cells. This would give them an advantage in competition because they could increase their intake of oxygen. It works perfectly, the same thing happen when staying at altitude. Today this is not legal (cheating), so now they have to actually stay at high altitudes for their training (as if that is less cheating).
Anyway, you can adapt to altitude, but it takes time, months.
