British former special forces soldiers made history by summitting Mount Everest within five days without acclimatising on the mountain.
According to BBC, the team of four British climbers, including a UK government minister, conquer the highest peak in the world, Mount Everest, using an innovative method on Wednesday, May 21, 2025.
They became the first climbers in the world to summit Everest by using xenon gas that reduces the acclimatisation period which is usually required during such a feat.
Climbers usually spend six to eight weeks on Everest before summiting to acclimatise, but the xenon gas helped the British to pre-acclimatise to low oxygen at high altitudes without spending weeks.
However, the science behind using xenon gas remains contentious, and the mountaineering industry has criticised it and raised concerns.
International Climbing and Mountaineering Federation on xenon use
The International Climbing and Mountaineering Federation, in a statement in January 2025, highlighted the negative impacts of using xenon gas.
It stated, “According to current literature, there is no evidence that breathing in xenon improves performance in the mountains, and inappropriate use can be dangerous. 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," it added.
Not the fastest Everest time
These climbers made a record to summit Everest without acclimatising in the Himalayas, but it is still not the fastest Everest time. The record still belongs to Lhakpa Gelu Sherpa, who ascended the mountain from base camp to summit in 10 hours and 56 minutes in 2003.
Expedition organiser Lukas Furtenbach told the BBC, “They started on the afternoon of 16th May and summited on the morning of the 21st, taking four days and approximately 18 hours... The team made a three-month acclimatisation programme in simulated altitude before coming to Nepal.”
The former British team was accompanied by five Sherpa guides and a cameraman, reached the 8,849-metre (29,032-foot) summit early on Wednesday, and started to descend soon afterwards.
