Altitude

Lhasa, Tibet is about as high as Mt. Cook. That means there is a period of adjustment when you get here from being at about sea level.
This adjustment is kind of like going through a hangover - you get all the wonderful benefits of headaches, nausea, dehydration, general aches, dryness and groans without having to go through the hassle of "going out for drinks" with your "mates"! (Another symptom is it turns you into a sarkie grump.)

The first day and night were pretty bad, but I think my respiration and heart rate are beginning to adjust to having only 60% oxygen content as at sea level. Just checking the place out... pretty cool (heh) so far! And so dry that I get shocks off anything water I touch.