Four former British special forces soldiers have made headlines by scaling Mount Everest in less than five days, bypassing the traditional acclimatisation period. Their record-setting climb was made possible through a high-speed expedition that used xenon gas to help them prepare for the extreme altitudes. This innovative, yet controversial method has stirred debate within the mountaineering community.
Among the climbers was Alastair Carns, a UK government minister and veterans minister. The team successfully reached the summit of the world’s tallest mountain early on Wednesday, marking a notable achievement in mountaineering. They employed a method that allowed them to pre-acclimatise to the thin air at high altitudes using xenon, a gas not typically associated with mountaineering.
Normally, climbers spend six to eight weeks on Everest to adjust to the altitude. However, the organisers of this expedition claim xenon allowed the team to ascend rapidly without experiencing the usual symptoms of altitude sickness. Despite the record, it was clarified that this was not the fastest ascent overall—Lhakpa Gelu Sherpa still holds that title, having ascended from base camp to the summit in 10 hours and 56 minutes back in 2003, but only after acclimatising on the mountain.
The British team, supported by five Sherpa guides and a cameraman, reached the Everest summit at 8,849 metres (29,032 feet) and began descending shortly afterward. Lukas Furtenbach, the expedition organiser, said, “They started on the afternoon of 16th May and summited on the morning of the 21st, taking four days and approximately 18 hours.”
Traditionally, climbers spend several weeks at Everest, moving between base camp and progressively higher camps to allow their bodies to adjust to lower oxygen levels. This slow process is crucial because, above 8,000 metres—known as the “death zone”—oxygen availability drops to one-third of that at sea level, posing significant risks.
Instead of undergoing the usual acclimatisation on the mountain, the four men completed a three-month pre-acclimatisation program using special hypoxic tents. These tents simulate high-altitude conditions by removing oxygen from the air with the help of a generator, mimicking the oxygen levels found on Everest. The team slept in these tents for six weeks before departing for Nepal.
Once in Nepal, they flew from Kathmandu to Everest base camp and began their climb immediately. Like other climbers, they used supplemental oxygen during the ascent. But the key difference was the pre-expedition use of xenon gas, inhaled at a German clinic two weeks before the trip. “It helps to protect the body from altitude sickness,” said MrFurtenbach.
The theory behind xenon use is that it boosts the production of erythropoietin, a protein that increases red blood cell count, thereby improving the body’s ability to carry oxygen. This mechanism could help the body combat hypoxia—a condition triggered by low oxygen levels. However, the scientific consensus on the effectiveness of xenon remains unsettled, and experts are calling for more research.
The use of xenon in mountaineering has drawn criticism from some in the industry. The International Climbing and Mountaineering Federation issued a warning earlier this year, stating, “According to current literature, there is no evidence that breathing in xenon improves performance in the mountains, and inappropriate use can be dangerous.”
They added, “Acclimatisation to altitude is a complex process that affects the various organs/systems such as the brain, lungs, heart, kidneys and blood to different degrees, and is not fully understood. From a physiological point of view, a single, one-off drug cannot be the key to improved acclimatisation or increased performance.”
Adrian Ballinger, a seasoned expedition leader whose team ascends Everest from the Chinese side, supports pre-acclimatisation through hypoxic tents but opposes the use of xenon gas. “If you’re promoting xenon as a performance enhancer, but you’re not also willing to examine what that means for fairness and integrity in the mountains, it’s a problem,” he told the BBC. “People are grasping at shortcuts instead of doing the real work of acclimatisation and training.”
The success of the British team has sparked concerns that others may try to replicate this method. Some worry this could fundamentally change the mountaineering experience and impact the tourism economy in Nepal, which relies heavily on long-duration expeditions.
“If that happens then it will certainly have a direct, negative impact on the tourism industry as the length of time mountaineers stay will come down significantly,” warned Damber Parajuli, president of the Expedition Operators Association of Nepal. He also questioned whether such climbers should even be awarded official summit certificates. “Acclimatising on the mountains is the basic rule of mountaineering. If that is not done then authorities should not be giving them certificates certifying that they climbed the mountain.”
Nepal’s tourism officials said they had not been informed that the team would attempt the summit without standard acclimatisation. “Now that we know about it, we will be discussing the issue and decide on our future course of action,” said Narayan Regmi, director general at Nepal’s department of tourism.
The motivation behind such a rapid ascent was not just about speed and setting records. According to Furtenbach, a shorter expedition also comes with environmental and health benefits. “A shorter expedition has a lower carbon footprint and less ecological impact,” he said. “And it is safer for climbers because they can climb the mountain in good health and they are exposed to high altitude risks and mountain hazards for shorter time compared to when they are acclimatising on the mountain.”
Whether the British team’s method will become the new norm in mountaineering or be deemed unsafe and unethical remains to be seen. For now, their record-setting ascent stands as a bold challenge to traditional climbing norms—and a focal point for an evolving debate on the future of high-altitude expeditions.
