Originally Posted by
Geordie405
I think the highest I have been was to the Jungfraujoch in Switzerland and that's a little over 11300 feet above sea-level. I really did notice the effects of being at altitude, despite doing nothing more strenuous than walking around, having a hot chocolate and taking photos!
My record was there too, I did the hike to the Mönchsjochhütte and back, that's just a few feet below 12k. I think I spent a total of 4 to 4.5 hours up there before I felt some light headache starting, that's when I decided to get the train back down again. It probably didn't help that I was home, basically at sea level, two days earlier. The oxygen saturation in my blood really dropped too, at home I would see a doctor immediately with those values.
I think I need to check my insurance too, although those heights (outside of aircraft) are more than rare for me.