自宅でできる高所順応　コロナ禍のヒマラヤ遠征で注目

【カトマンズＡＦＰ＝時事】米国の登山家アカシュ・ネギーさん（２９）は、世界最高峰のエベレスト登頂に向けて訓練を重ねた──ここ数週間、米ニュージャージー州にある自宅リビングにセットしたテントで寝泊まりをしたということだ。（写真は低酸素テントを利用するアカシュ・ネギーさん。米ニュージャージー州の自宅で）
　ネギーさんが使ったのは低酸素テントだ。新型コロナウイルスの流行が続くネパールでの滞在期間を短縮させ、ウイルスとの接触リスクを減らす目的で、遠征前にこれを利用する登山者が増えている。
　４月に春の登山シーズンが始まって以来、今年はすでに３０人以上が健康上の理由からベースキャンプを去っている。そのうちの３人は新型コロナウイルスへの感染が確認された。
　通常、登山者らはカトマンズから標高５３６４メートル地点のベースキャンプまで８日間かけて移動する。この間、高地への環境に少しずつ体を慣らすのだ。
　今回、遠征のために十分な休みを確保できなかったというネギーさんだが、低酸素テントの利用でベースキャンプまで時間をかけて移動する必要がなくなり、ほっとしたと話す。
　遠征前、ネギーさんはドーム形のテントで１日最長１０時間眠った。テントは酸素を窒素と置き換えて低酸素状態をつくる装置につながっている。高地トレーニング用のマスクを着用しながらフィットネスバイクも利用した。
　こうした自宅での高地順応トレーニングを通じて、エベレスト遠征の期間を８週間から４週間に短縮できる可能性がある。
　自宅での低酸素トレーニングを経た短縮期間の遠征には、最大で８万５０００ドル（約９４０万円）かかる。これは通常のエベレスト登頂に要する費用の約２倍にあたるという。
　しかし、このような高額な費用にもかかわらず、肺機能の強化を求めるアスリートらからの人気はプロアマ問わず高まっている。

■ワクチン接種を受けていても…
　人口約２８００万人のネパールでは、１日当たりの新規感染者が数千人に上っている。また今季、登山許可証の発行件数が過去最多となる４０８件を記録。登山者の大半が地元ガイドのサポートを受けるため、８００人以上が登頂を目指すことが見込まれている。
　こうした状況の中、低酸素トレーニングを取り入れているスペインの登山家フランシスコ・マルティンさん（３４）にとっても、遠征期間の短縮は大きな意味を持つ。
　「新型コロナウイルスのワクチン接種を受けていても、自らが（ウイルスを）持ち込む恐れはある」とマルティンさん。「ワクチン未接種の人との接触を最小限にしたい。一番避けたいのは、誰かを病気にさせること」だと語る。マルティンさんは標高世界第４位のローツェ登頂を目指している。【翻訳編集ＡＦＰＢＢＮｅｗｓ】

〔ＡＦＰ＝時事〕（2021/06/08-13:57）

Mountaineer Akash Neggi is fully prepared to take on the world's highest mountain -- after spending several weeks sleeping in a tent in his living room in New Jersey.
As Nepal battles Covid-19, a growing number of climbers are using oxygen-deprivation tents ahead of their expeditions to reduce exposure to the coronavirus by cutting down the length of their Himalayan adventure.
Mount Everest aspirants typically spend eight days trekking from Kathmandu to base camp at 5,364 metres (17,598 feet), using the journey to acclimatise to high-altitude conditions.
But this year, more than 30 mountaineers have already been evacuated from base camp for medical reasons since the start of the spring climbing season in April -- with three known to have contracted the coronavirus.
Neggi, a seasoned climber, used the chamber as he did not have enough vacation leave for his expedition. But he is now relieved to have avoided the extra days on the ground.
During the trek, people were staying at tea houses together and meeting other teams, he told AFP in Kathmandu ahead of his helicopter flight to base camp.
It is hard to say where people were infected, but I am glad I was able to skip that crowd.
- 'Hard to breathe' -
The 29-year-old American slept in the plastic-domed tent -- attached to a machine that sucks oxygen from the air and replaces it with nitrogen -- for up to 10 hours every day.
Neggi also wore a face mask attached to a device that reduced his oxygen supply as he exercised on a stationary bike.
Another mountaineer, 34-year-old Francisco Martin from Spain, would lie in bed every day with his head and some of his upper body covered by a sealed plastic frame attached to a machine.
For two months, he slept and worked on his laptop inside the chamber as his body adapted to the lower levels of oxygen ahead of an expedition to Lhotse, the world's fourth-highest mountain.
At the very beginning... it was very hard to breathe as I was acclimatising, Martin told AFP from his New York home.
Now, I'm completely good. I can do phone calls. I have done jobs interviews at 6,400 metres (in) my tent and I have been... fine.
Acclimatising at home could mean reducing an Everest trip from eight weeks to just four, but it comes with a hefty price tag.
Climbers can pay up to $85,000 for their shortened trek and tent experience -- almost double some estimated costs to scale Everest.
But the method -- which alone can cost thousands of dollars -- is gaining popularity among professional and amateur athletes wanting to improve their lung capacity.
By spending time in a hypoxic tent, mountaineers also go through the arduous process without sacrificing their strength ahead of their Everest attempt.
You don't get that weak as you would when you stay for eight or nine weeks at high altitude, Lukas Furtenbach, who runs Austria-based Furtenbach Adventures, told AFP.
- Avoiding Everest crowds -
Brian Oestrike, the chief executive of the world's biggest supplier of such chambers, Hypoxico Altitude Training Systems, told AFP the pandemic has seen more climbers using their equipment.
Even those not planning for shorter expeditions are using the items as they want to reduce their virus exposure by training indoors, he said.
With Nepal issuing a record 408 permits this year and most Everest climbers led and supported by local guides, more than 800 mountaineers could be making their way to the summit this season.
The nation of 28 million people has been recording an average of 9,000 daily Covid-19 infections recently, making adventurers such as Martin grateful for the shortened trip.
Despite being vaccinated against Covid, I don't know if (I) can be a carrier, he said.
So I also wanted to minimise potential exposure to unvaccinated people... (the) last thing I want to do is get anyone sick.