Last Tuesday, May 20th, I checked on the news of the “xenon climbers” attempting to reach the top of Chomolungma and be back home in the UK within a week. They had just left London by plane the previous Friday and they were in Camp IV. Reports of heavy winds threatened the goal. As climber and author Mark Horrell commented:

Love ’em or hate’ em, 4 days from the UK to Camp 4 on Everest is definitely a first 😲–via BlueSky

That day I was thinking, Great, now they’ll get delayed and we’ll have to watch another London-to-Chomolungma-to-London attempt. But they pulled it off: Expedition organizer Lukas Furtenbach told the BBC, they summited “on the morning of the 21st, taking four days and approximately 18 hours.”

There have been at least two other claims to have done it faster or the same thing, but Furtenbach’s is the most credible to date. He announced it back in January, though some details were sparse. The others seem to be publicity chasers and copycats. But I could be wrong, we’ll see.

Only time will tell how significant and lasting this event will be, but it’s worth keeping in mind. This is different than a fastest known time of the typical sense. Beating the clock from base camp to the summit is akin to a track meet. If xenon has a benefit, and I don’t know if it does, then it could influence climbs, high altitude rescues.

WHAT WE’VE BEEN TOLD

I have several questions about all this xenon stuff, but first I wanted to put down some of the essential facts about the preparation and the ascent, including a timeline first. So here we go:

Furtenbach is an established commercial expedition guide service. He’s in Everest, Inc by Will Cockrell (2024) (my review of which will be in the 2025 AAJ.) He wasn’t the first to guide on Everest, of course, but he has been running a steady business. In January 2025, he announced that four climbers would climb Everest within a week using xenon gas. These are the four climbers:

• Garth Miller
• Alastair Carns
• Anthony Stazicker
• Kev Godlington

More recently we learned that the climbers would be highly fit and conditioned athletes, would be sleeping in hypoxic tents for two months, use supplemental oxygen on the climb, and be supported by a team of climbers that acclimatized the traditional way. This was the support team, and five of which, accompanied the four UK climbers to the top:

• Pasang Tendi Sherpa, Guide
• Pemba Rinji Sherpa
• Nima Nuru Sherpa
• Gelu Sherpa
• Pemba Rickchhen Sherpa
• Karma Sherpa
• Mingma Chhiri Sherpa
• Phu Dorji Sherpa

Photographer Sandro Gromen-Hayes, who did not undergo the special treatment, also accompanied the climbers and the support team.

Lastly, for two weeks prior to the attempt, the four climbers underwent a “xenon therapy,” breathing in the gas. The purpose of the gas, Furtenbach says, is to minimize the effects of altitude sickness in the rapid ascent. (Also see this from BBC.)

Here was the final timeline of the airport-to-summit-to-airport ascent:

• Miller, Carns, Stazicker, and Godlington boarded a plane in London’s Heathrow airport bound for Everest on Friday, May 16, 2025.
• Reached camp IV on Monday, May 19, 2025.
• Summited at 7:15 a.m. Nepal time on Wednesday, May 21, 2025.
• Returned to Heathrow Airport at 6:05 a.m. on May 23, 2025.

This amounts to an elapsed time of six days and 13 hours since departure, according to ExplorersWeb dot com.

OUTSTANDING QUESTIONS

First, I am glad nobody was hurt in this. I mean, I’m glad that it didn’t seem to be an outright stunt. It was more responsible than I feared when we heard Furtenbach’s announcement back in January. It also makes some sense to me that xenon was in addition to employing several other tactics, such as hypoxic tents and supplemental oxygen. So for some questions:

• Could the ascent have been successful with their pre-acclimatization program, mainly with hypoxic tents and strong fitness regimen, without the xenon?
• Supplemental oxygen is a well-established performance enhancer, but to what degree would this fend off altitude sickness?
• Does the May ascent with xenon prove anything about xenon? I don’t think so, and I think we need more samples.

This “xenon climb” was a demonstration, but hardly a scientific exercise. I wish there was another team that would have done everything Miller, Carns, Stazicker, and Godlington did, minus the xenon therapy, to compare it to.

If we wanted to spend a longer duration at altitude, would xenon therapy help beyond this Everest smash-and-grab?

I don’t know the answers and won’t for a while, but this still has potential. Potential for what? I am not sure, because it could become another list of forgettable firsts.