Oxygen 101

One of the most rewarding 'side effects' of my high altitude and Everest experiences has been the opportunity it has presented to better understand my own physiology and the changes that are taking place within the body over the course of an expedition. As the saying goes, "knowledge is power" -  the trick is to learn to 'manage' these changes and work with them rather than against them...

The lungs contain approximately 300 million tiny air sacs, called alveoli. Each sac has a thin membrane, through which oxygen in the air is absorbed into the bloodstream through diffusion, and carbon dioxide is expired from the blood to the air in the lungs, before being exhaled. The less air pressure there is, the less oxygen there will be in each breath, and the less will pass through the membranes into the blood.

The logical answer is to breathe more deeply and more frequently – sadly there are many things about high altitude mountaineering that aren’t as simple or logical as they might seem..!. It’s exhausting to breathe so hard and since the thin air is very cold and very dry and it can be also be painful. There is a serious danger of freezing the throat and lungs; a cough is inevitable at altitude, and can rapidly become so bad that muscles in the chest wall may be torn – or that ribs can be broken which is what happened to me in my 2010 attempt. This cough is often referred to as the ‘Khumbu Cough’ or the ‘high altitude hack’.

The body deals with all these problems by increasing the efficiency of oxygen intake from the lungs and transport in the blood. An important part of acclimatisation is the production of more red blood cells, which takes place mainly during rest which is why we spend so much time resting at Base Camp, Advanced Base Camp and the North Col.... See the next blog entry (27 March) for additional details...

North Col Camp at 7100m