Tibet Day 1, Acclimatising in Lhasa

Flying into high altitude locations above 3000m can be challenging. Firstly the thinner air means that aircraft landings occur at higher speed because the wings generate less lift; and with Lhasa at 3500m, the increased landing speed compared to that at take-off at sea-level is noticeable looking out of the window.

Secondly, once you're there you have less oxygen intake in every breath; at 3500m there's 34% less oxygen than at sea-level. You notice it even climbing just a few stairs as you're more out of breath than usual. You need to acclimatise to this change and that's what our first few days in Lhasa are about. The body slowly adjusts, producing more red blood cells and opening up parts of your lungs not normally used. But it also causes more fluid to leak from capilliaries into the lungs and brain and without our acclimatisation this can lead to problems. Diamox is a drug commonly used to reduce the affects and we've all got tablets to help us. Acute Mountain Sickness or AMS, is a well known condition and affects everyone differently, but it is potentially fatal and so we take it seriously. Even Alex, the seasoned guide, says he's felt it here and that we need to take extra care because we've flown in to 3500m (and will stay at high altitude) without the gradual ascent normally included in our trips.

Mark, Neil and Matt have seen some symptoms, headache, nausea and loss of appetite for example so it's good that we are taking it relatively easy in these first few days. Later we will reach 5200m at Everest Base Camp, where we will spend a night in freezing conditions and with only 55% of that precious oxygen, so this acclimatisation is essential.

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