Does being young and fit actually make a difference? I'm asking because when I went to Tibet I read a lot about the effects of altitude (living high, not flying high), and apparently you couldn't tell how anyone would react; some young fit people had really problems and had to descend, and vice versa. I know I was happily shopping in the market (hard to stop me shopping
) and sprinting across roads on my first day in Lhasa, while some people half my age went to bed. Is flying different? Can you tell how people will react?