ALTITUDE IN THE HIMALAYA

Acclimatising to the tallest mountain range in the world takes time and preparation. We departed equatorial Kathmandu, and with a certain amount of trepidation flew to the gateway of the Himalaya; Lukla. After 45 minutes of flying over high passes, the plane dramatically veered right to approach a short and steep runway perched halfway between the valley floor and the mountains above. Lukla's runway was one of our grandfather's major projects, providing an avenue to support the building of schools and hospitals in the Khumbu. Sitting at 2800 meters, Lukla is the initiation for your body's adaptation process to the thin Himalayan Acclimatising to the tallest mountain range in the world takes time and preparation. We departed equatorial Kathmandu, and with a certain amount of trepidation flew to the gateway of the Himalaya; Lukla. After 45 minutes of flying over high passes, the plane dramatically veered right to approach a short and steep runway perched halfway between the valley floor and the mountains above. Lukla's runway was one of our grandfather's major projects, providing an avenue to support the building of schools and hospitals in the Khumbu. Sitting at 2800 metres, Lukla acts as the site of initiation for your body's adaptation to the thin Himalayan air.

Altitude effects people in different ways and at different times; while some people feel strong straight away, others take longer to adjust. The climb from the town of Phakding to Namche, the Sherpa capital, is notorious. The Namche hill rises up out of the valley and tests the fitness and acclimatisation of everyone who tries to trek up into the high Himalaya. During our trek, I was lucky enough to be feeling strong and was able to race on ahead, topping the hill in 35 minutes.

This process of acclimatisation is slow and continues as we progress up through the mountains. Moving quickly can be dangerous; if you were to instantly ascend from sea level to the summit of Everest at 8,848m you would lose consciousness in 90 seconds. By climbing gradually your body is able to physiologically adapt to altitude. This takes time. From Namche we headed up valley toward the birthplace of Tenzing Norgay, near Thame village. This was a gradual ascent, which allowed our bodies to slowly adapt to the increasingly alpine environment.

Despite the difficulty of high altitude, there are many strategies that we use to ensure an easier and more enjoyable experience. Some of these strategies are simple, such as plenty of hydration, which is made easy with the abundance of yak milk tea at every lodge and at each encounter with the local Sherpa people. Others are less self-evident, like taking medication that assists with high altitude, such as Diamox (which has a few unfortunate but manageable side effects), and following one of the adages of high altitude mountaineering: 'Climb High, Sleep Low'.

From Thame, my brother and I, along with our father Peter Hillary, climbed from 1,300 metres to 5,050 metres on Sunder peak. It was a breathless place up there, and from our vantage point we had dramatic views across the Himalayas: Ama Dablam, Everest and Cho Oyu on the Tibetan border, and to the west, the snowy peaks of the Tashi Laptcha Pass. Pushing up to these high altitudes, the three of us felt a heavy-headed sensation, which is the precursor to an altitude-induced headache. But descending promptly releases the pressure and improves the body's ability to move higher for longer periods of time. As we descended towards Thame monastery, we all felt flooded with energy.

In the coming weeks my brother and I will be gaining more and more altitude as we approach Everest basecamp (5,360 metres), and ultimately push for the summit of a nearby mountain; Ama Dablam (6,856 metres). Jumping to extreme altitudes such as this take a huge toll on the body and we are aware of the dangers of ascending too quickly. If we don't take the necessary steps we could end up with some of the symptoms of high-altitude sickness, such as pulmonary or cerebral oedema. In three weeks we will arrive at Ama Dablam basecamp.

Alexander and George Hillary

Photography by Alexander Hillary