Kilimanjaro Acclimatisation The main problem faced by trekkers is trying to climb too quickly. From a medical perspective, we are trekking in very high altitude (up to 5,500m) and in extreme altitude (summit day above 5,500m). At sea level, the standard barometric pressure is 101 kPa. At 5,895m on the summit of Kilimanjaro, the standard barometric pressure is 50 kPa. This lower oxygen pressure means that there are fewer oxygen molecules in the same volume of air - there is only 49% of the oxygen available compared to sea level. Your body reacts to this lower oxygen level in a variety of ways - for example, your respiration (breathing) rate increases, and your body starts to generate more red blood cells. The respiration increase begins immediately, but the production of extra red blood cells takes longer. We are following a gradual ascent profile and have programmed an extra night at Mawenzi Tarn Camp, with the opportunity to gain extra height on Mawenzi Ridge on Days 4 & 5. This ensures that we give our bodies more time to acclimatise to the lower oxygen levels before summit day. We recommend that you discuss with your GP the option of using Diamox (acetazolamide) to help prevent Acute Mountain Sickness (AMS).