The first ascent of Mount Everest, 1953: the solution of the problem of the ‘last thousand feet’

Pugh's pioneering work at high altitude on Cho Oyu in 1952 dictated the framework for the first ascent of Everest in 1953. He demonstrated that a flow rate of 4 litres of oxygen per minute in the open circuit sets was necessary to provide a boost to performance sufficient to climb Everest from a high camp, at 8600 m, with a safe return to the South Col (8000 m) in one day.

Sleeping oxygen mitigated high altitude deterioration, as did Pugh's insistence on a very high fluid intake to combat dehydration. Together with adequate protection from the cold, which was less severe than predicted, these strategies resulted in all climbers who went above 8000 m being in good physical and mental condition.