A 45-year-old Nepali guide, Tenzing Norbu Sherpa, has been found alive on Mount Everest after being missing for three nights, a feat that mountaineering bodies are calling a ‘miracle’ of physiological endurance. UK organisations, including the British Mountaineering Council, have applauded the survival, which carbon-dating of his ordeal suggests occurred in the ‘death zone’ above 8,000 metres where atmospheric oxygen is one-third of sea level.
Norbu, guiding a commercial expedition, vanished during a summit push on May 18, likely from a weather-induced dislocation from his client. He survived by finding a shallow ice cave, wrapping himself in his down suit, and melting snow using body heat alone. To understand the scale of this: the human body at sea level consumes oxygen at a rate of 250 millilitres per minute at rest. At 8,800 metres, with the partial pressure of oxygen falling to 34% of normal, even this basal demand forces the heart to pump at 140 beats per minute to deliver enough oxygen to the brain. Hypoxia sets in within 15 minutes of exposure. Norbu endured for 72 hours.
The rescue, performed by two fellow Sherpas and a US climber, found him walking down the South Col route, severely frostbitten but conscious. His core temperature, when measured on the helicopter ride to Lukla, was 35.2°C, just above the threshold for moderate hypothermia. This suggests he managed to stave off a metabolic catastrophe through two mechanisms: extreme vasoconstriction of extremities (shutting off blood flow to fingers and toes to preserve heat for the brain and heart) and possibly a paradoxical warming from the ‘diving response’ triggered by intense stress. The latter, often invoked in near-drowning cases, can reduce oxygen consumption by 50%.
Norbu’s survival has immediate implications for high-altitude rescue protocols. Currently, the maximum estimated survival time for an immobilised climber in the death zone is 48 hours without supplemental oxygen. His case extends that window. The technical challenge remains: in the thin air, a helicopter’s rotor blades lose 40% of their lift at Everest’s summit. The rescue took place at 7,800 metres, where the air density is 48% of sea level, requiring a Westland Puma helicopter with two engines to make a high-risk hover.
The UK mountaineering community, which has seen 35 deaths on Everest since 2000, is recalibrating its advice. The British Mountaineering Council issued a statement praising ‘the Sherpa tradition of self-sufficiency’ but also calling for mandatory biometric monitors on all altitude guides. The science is clear: the human body can withstand a three-day oxygen debt only if it can maintain core temperature above 35°C and fluid intake above 1.5 litres per day. Norbu had no food and only ice melt.
His recovery will now be studied by the Institute of High Altitude Biology in Kathmandu, which specialises in such extreme survival cases. One likely factor is his lifelong residence at 3,900 metres in the Khumbu valley, which has given him a genetic adaptation: Andean and Sherpa populations have higher capillary densities and more efficient mitochondria, using oxygen 30% more efficiently than lowlanders. Even so, his frostbite will almost certainly lead to digit amputations.
As I file this from the climate desk, the irony is not lost. Everest’s jet stream has weakened due to warming, prolonging summit windows but also creating more unpredictable storms. Norbu survived a sudden blizzard. The biosphere is pushing back against our oldest traditions. For now, though, the physics of a body refusing to die has given the mountaineering world an anomaly to ponder.
