Acclimatizing for Kilimanjaro
Altitude sickness is avoidable. The only surefire way to to do is to take your time climbing Kilimanjaro. Opting to save money by climbing the mountain as quickly as possible is a false economy: the chances are you will have to turn back because of altitude sickness and all your efforts (and money) will be wasted.
According to the Expedition Advisory Committee at the Royal Geographical Society, the recommended acclimatization period for any altitude greater than 2500m is to sleep no more than 300m higher than your previous night’s camp, and to spend an extra night at every third camp. But if you were to follow this on the Kilimanjaro’s Marangu Route, for example, from Mandara Huts you would have to take a further eight nights in order to safely adjust to the Kibo Huts’ altitude of 4700m - whereas most trekkers take just two days to walk between the two.
Take a pre-acclimatization climb before tackling Kilimanjaro
The EAC realize that the short distances and high per diem cost of climbing Kilimanjaro make this lengthy itinerary impractical, so instead they recommend a pre-trek acclimatization walk on Mount Meru or Mount Kenya (4895m to Point Lenana). This is an excellent idea if you have the time and are feeling fit, and providing you do one of these walks immediately before you climb Kili, these treks can be beneficial - and the views towards Kilimanjaro from Meru are delightful too.
Take rest days on Kilimanjaro
But what if you don’t have the time or money to do these other climbs? The answer is to plan your walk on Kilimanjaro as carefully as possible. If you have enough money for a ‘rest day’ or two, take them. These ‘rest days’ are not actually days of rest at all - on the Marangu trail, for example, guides usually lead their trekkers up from Horombo Huts to the Mawenzi Hut at 4600m before returning that same afternoon. But they do provide trekkers with the chance to experience a higher altitude before returning to below 3000-4000m again, thereby obeying the mountaineers’ old maxim about the need to ‘climb high, sleep low’ to avoid mountain sickness.
Choose a ’slow’ route up Kilimanjaro
The route you take is also important. Some of the routes - the Machame, Lemosho and Shira trails via the Barafu Huts, for example - obey the mountaineers’ maxim on the third or fourth days, when the trail climbs above 4500m before plunging down to an altitude of 3985m at Barranco Camp where you spend the night. Some of the shorter trails, however, do not: for example, it is possible for a trekker walking at an average pace on the Marangu or Rongai trails to reach the Kibo Huts in three days and attempt an assault on the summit for that third night. This sort of schedule is entirely too rapid, allowing insufficient time for trekkers to adapt to the new conditions prevalent at the higher altitude.
This is why the majority of people fail on these trails and it is also the reason why, particularly on these shorter trails, that it is imperative that you take a ‘rest day’ on the way up: to give your body more time to acclimatize.