Altitude effects on stomach upsets
I was reading an Australian report the other day on an F/O in a Sabb 340 who suffered debilitating stomach cramps (or something along those lines) as the aircraft climbed to altitude - went onto 100% oxygen, the captain diverted, and as they descended onto the approach, he became sufficiently fit to participate in the landing actions.
This got me thinking - 100% oxygen is a standard panacea for all ills on an aeroplane, and often does make a big difference. However, the implication here is that the thing that really made a difference to him was reduced cabin altitude (whilst still on 100% O2) rather than the partial pressure of oxygen.
Can anybody offer a mechanism whereby increased pressure / reduced cabin altitude will improve somebody's condition, where increasing partial pressure of oxygen alone would not?
G