Climbing Through the 'Death Zone' - the Art of Acclimatization

Acclimatizing on 8,000-meter Peaks

Climbing the highest peaks in the world, those exceeding 8,000 meters, requires changes to one’s physiology. Beyond an impressive climbing resume and peak physical conditioning, actual bodily adjustments must take place. As climbers enter the ‘Death Zone’ (above 26,000 ft.), they will experience approximately 33% of the oxygen we enjoy at sea-level. If one was transported to the top of Mt. Everest by plane and dropped off, they would quickly lose consciousness and die.

The process intended to counter the effects of reduced oxygen is referred to as ‘acclimatizing’. This process consists of climbing mountains slowly, and incrementally – attaining higher and higher altitudes, then returning to lower altitudes to rest and prepare for another rotation at elevated altitudes. The regimen results in climbing portions of 8,000-meter peaks several times before attempting the summit.

Through ‘acclimatizing’, the body produces red cells at an amplified rate and allows the body to become more efficient with less air. Ultimately, climbers can survive on the highest reaches of mountains including Mt. Everest. On Mt. Everest, conventional acclimatizing can take up to two months while climbing up and down the mountain.

Accelerating the Process

To accelerate the acclimatization process, climbers are adding smaller mountains to their Mt. Everest climbing itineraries. For example, climbing teams will include a peak like Loboche East, a 20,075 ft. peak located enroute to Everest Base Camp to their programs. Mountaineers include such peaks to push their physiologies at higher altitudes. This addition can accelerate the acclimatization process. And now, climbers are turning to advancements in technology to circumvent this process even further.

Acclimatization Technology

To avoid numerous laps through the treacherous Khumbu Icefall, some climbers are turning to technology. Endurance athletes have utilized ‘hypoxic tents’ for years to improve performance. Now climbers are using improved technology to start the acclimatization process in the comfort of their own homes, months before departing on expeditions. The original ‘tents’ have evolved into bags, that cover the head and torso only, connected to an air tube and motorized unit. The unit gradually mimics higher and higher altitudes by reducing oxygen levels while the climber sleeps. This takes place for approximately two months.

Users of these systems seek to emulate an elevation of 18,000 ft. prior to going to Everest Basecamp, or other 8,000-meter peaks. At Everest Basecamp the amount of air (The oxygen component does not change) diminishes to roughly 50% of that at sea-level. Throughout the process, climbers check their blood oxygen levels and resting heart rates. This process can reduce the duration of an Everest expedition by more than 50% - approximately 2 ½ months to 1 month. For some, this remains too long.

Xenon Gas

An Everest expedition team intends to climb the highest mountain in the world over a 4-5 day period this spring. To do this, they will chemically supercharge the acclimatization process utilizing a new method – inhaling xenon gas. They will start sucking on the gas prior to setting out for the summit of Everest – no trek in, no rotations up and down the mountain, no time at Base Camp. In a follow-up article I will examine this massive shortcut, and the reaction from the climbing community and ramifications for mountaineering’s future. (Related Article)