Understanding Hypoxia and Supplemental Oxygen on Mount Everest

Mount Everest, the world's highest peak, presents a formidable challenge to climbers due to its extreme altitudes and the resultant thin atmospheric air. While supplemental oxygen tanks are commonly used to combat the reduced oxygen levels, a surprising number of climbers still suffer from hypoxia. This article explores the factors contributing to this issue and sheds light on the complexities of high-altitude mountaineering.

Factors Contributing to Hypoxia

Hypoxia, or low oxygen levels in the body, is a common phenomenon among climbers even when using oxygen tanks. Several factors contribute to this issue:

Altitude

At altitudes above 26,000 feet (7,900 meters), known as the Oxygen Supply Limit, oxygen levels are significantly lower. While climbers use oxygen tanks to alleviate this issue, these tanks can run low or empty due to mismanagement, unexpected delays, or excessive physical exertion during ascent. Some climbers might think they can acclimatize without supplemental oxygen, leading to delays in re-supply and increased risk of hypoxia.

Physical Exertion

Climbing at high altitudes requires significant physical exertion. Even with supplemental oxygen, the oxygen demand can still be insufficient, resulting in hypoxia. This is particularly true in areas of significant physical exertion, such as traversing through steep and treacherous terrain.

Acclimatization

Not all climbers acclimatize effectively to high altitudes. Those who ascend too quickly may not give their bodies enough time to adjust, leading to altitude sickness and hypoxia. Proper acclimatization is crucial for successfully reaching the summit of Mount Everest.

Equipment Issues

Problems with the oxygen delivery systems, such as leaks or malfunctions, can render supplemental oxygen less effective. These issues can occur due to mechanical failures, environmental factors, or incorrect usage by climbers.

Individual Variability

Each climber's physiology is different, affecting their susceptibility to altitude sickness and hypoxia. Some people are more susceptible to these conditions, regardless of the use of supplemental oxygen.

Environmental Factors

Extreme cold and harsh weather conditions can also affect the performance of oxygen systems, making it harder for climbers to breathe effectively and maintain their oxygen levels.

The Purpose and Limitations of Supplemental Oxygen Tanks

Keeping weight to a minimum is critical for success on high-altitude climbs. Infinitely large oxygen tanks with an infinite supply of oxygen are not an option, as they would be inconvenient and dangerous to transport. The primary purpose of oxygen tanks is to provide just enough oxygen to keep a healthy, acclimatized person alive while they exert themselves in the death-zone—a place where they are slowly dying and unable to survive indefinitely without supplemental oxygen.

The system typically provides a supplemental oxygen flow of about 2 liters per minute into the mask. This oxygen enrichment simulates breathing at a lower altitude, making it seem as if the climber is 1,000 meters lower than they actually are. For example, a climber standing on the summit of Everest (8,848 meters) with oxygen tanks would effectively be breathing at 7,850 meters. However, even at this altitude, the climber is still in the death-zone and cannot survive indefinitely without oxygen.

The Human Toll of Hypoxia

While supplemental oxygen is a crucial tool, it does not eliminate the risk of hypoxia. The effects of these low oxygen levels can be severe and detrimental to the human body. Climbers experiencing hypoxia may lose mental acuity, become disoriented, and exhibit erratic behavior. For instance, a climber might remove their mask, insisting they are being poisoned by an evil gas.

Extreme cases of hypoxia can result in coma, irreversible brain damage, and even death. The psychological and physical toll of such an environment can be overwhelming, as exemplified in the case of Reinhold Messner, who described his 1980 solo ascent in these terms:

"I was in continual agony. I have never in my whole life been so tired as on the summit of Everest that day. I just sat and sat there, oblivious to everything. I knew I was physically at the end of my tether."

Messner's experience highlights the harsh reality of climbing Mount Everest, emphasizing the suffering and the perilous nature of the undertaking.

The Modern Approach to Climbing Everest

The modern era of Everest climbing has seen advancements in technology and scientific approach to minimize the risks associated with hypoxia. Teams like the Austrian outfit Furtenbach Adventures employ hypoxia tents, where climbers are pre-acclimatized to 7,000 meters. This enables them to reach the summit within 10 days of arriving at Base Camp.

Wearable wireless technology allows real-time monitoring of the climbers' vital parameters, such as oxygen saturation (SpO2) and heart rate, which helps the team make informed decisions. Radios facilitate communication between the base camp and climbers in the death-zone, enabling adjustments to oxygen flow as needed.

Doctor and team leader Lukas Furtenbach stressed the complexity of determining a specific SpO2 threshold to avoid hypoxia. He highlighted the importance of monitoring individual trends and vital signs in making critical decisions.

Despite these advancements, reaching the summit of Mount Everest remains a perilous endeavor, and hypoxia remains a constant risk. The modern approach aims to mitigate this risk, but it does not guarantee a safe ascent.

Clubbing on this inhospitable terrain, climbers must push themselves to the limit, and the results are a testament to their perseverance, determination, and the risks they are willing to take.