At the summit of Mt Everest – 8848 metres up – each breath delivers only a third of the oxygen it does at sea level imageBROKER/Alamy
MOUNTAINEERS Ralf Dujmovits and Nancy Hansen are no strangers to thin air, having collectively reached the summits of all eight of the world’s highest mountains. But when they entered the hypoxia chamber at the in May 2018, they were effectively climbing one of the highest peaks of their careers. After a two-week acclimatisation, they spent 16 days breathing air thinner than at Everest base camp – including four days at the equivalent of 7112 metres. This is just shy of the “death zone” over 8000 metres, where the lack of oxygen impairs climbers’ judgement and increases their risk of heart attack and stroke.
Time and again, the two mountaineers – and those observing them – questioned whether they should keep going, but they did. If Dujmovits and Hansen could show that humans can tolerate extended periods of low oxygen, known as hypoxia, it would pave the way for an even more ambitious experiment: to test whether, sometimes, it might even be beneficial to starve people of oxygen.
This may sound strange. After all, our organs and tissues need oxygen. Indeed, astonishingly low oxygen levels in people with covid-19 have (See “Happy hypoxia?”), and treatment . After a heart attack or stroke, people are routinely given oxygen too, to ensure their tissues don’t die.
Yet, for all this, surprisingly, there are hints that hearts and spinal cord injuries could heal faster if deprived of oxygen.…
