A revision of maximal oxygen consumption and exercise capacity at altitude 70 years after the first climb of Mount Everest

Abstract

On the 70th anniversary of the first climb of Mount Everest by Edmund Hillary and Tensing Norgay, we discuss the physiological bases of climbing Everest with or without supplementary oxygen. After summarizing the data of the 1953 expedition and the effects of oxygen administration, we analyse the reasons why Reinhold Messner and Peter Habeler succeeded without supplementary oxygen in 1978. The consequences of this climb for physiology are briefly discussed. An overall analysis of maximal oxygen consumption ((Formula presented.)) at altitude follows. In this section, we discuss the reasons for the non-linear fall of (Formula presented.) at altitude, we support the statement that it is a mirror image of the oxygen equilibrium curve, and we propose an analogue of Hill's model of the oxygen equilibrium curve to analyse the (Formula presented.) fall. In the following section, we discuss the role of the ventilatory and pulmonary resistances to oxygen flow in limiting (Formula presented.), which becomes progressively greater while moving toward higher altitudes. On top of Everest, these resistances provide most of the (Formula presented.) limitation, and the oxygen equilibrium curve and the respiratory system provide linear responses. This phenomenon is more accentuated in athletes with elevated (Formula presented.), due to exercise-induced arterial hypoxaemia. The large differences in (Formula presented.) that we observe at sea level disappear at altitude. There is no need for a very high (Formula presented.) at sea level to climb the highest peaks on Earth. (Figure presented.).