Supplemental Oxygen in the Death Zone

Final Summit Preparations

The Mt. Everest spring climbing season is nearing its conclusion, as climbing teams are completing final preparations before launching their summit attempts. Importantly, teams have been conducting rotations through the treacherous Khumbu Icefall, and higher to Camps 1-3. Prior to summit bids, teams will return to Everest Base Camp (“EBC”) for several days of rest while they wait for a favorable weather forecast of approximately 7-10 days before venturing beyond Camp 3 to Camp 4 (The South Col), and to the summit.

Thin Air

They have been 'working' the mountain for 5-7 weeks setting up camps with required supplies, ensuring that the mountain is ‘Fixed’ with rope from the Icefall to the summit, and acclimatizing to decreasing air at altitude. As one climbs higher the air gets thinner. Air is comprised of approximately 21% Oxygen, 75% Nitrogen, 3% Carbon Dioxide, and 1% other. This composition does not change at altitude, but the amount of air in the atmosphere does change. By the time a climber reaches the summit of Mt. Everest the air in the atmosphere is 60% less than at sea level. Consequently, the vast majority of climbers utilize supplemental oxygen to compensate for this reduction.

The additional Oxygen augments the natural acclimatization process, whereby the body increases red blood cell production to heighten hemoglobin concentration. This allows the body to do more with less. Notable climbers including Rienhold Messner (the first person to climb all fourteen 8,000 meter peaks without supplemental Oxygen), and Ed Viesturs (the first American to attain the same feat), have conquered the ‘Death Zone’ without such assistance. This is rare. Climbing Sherpas, and most climbers, augment their climbs with supplemental Oxygen to mitigate risk, and to maintain maximum strength to assist struggling or fallen climbers.