Sunday, 23 December 2007

Preparing for altitude

By the end of the week I will be enjoying (if that's the right word) the rarified air of Kenya's Rift Valley. Well to be more precise, the top of the western escarpment which rises to 2400 metres (8000 feet) above sea level. At that altitude the partial pressure of oxygen in the air is significantly lower than at sea level and you notice its effect by gasping for breath even walking up stairs !

Altitude has long been used by endurance athletes for improving performance and while the precise adaptations the body goes through are still not fully understood we do know the basics which go something like this: the partial pressure of the oxygen in the air forces oxygen through the tiny membranes in your lungs to where it binds with the iron containing haemoglobin in your blood before getting carried to the muscles where it unbinds and gets used to burn fuel (carbohydrates and fats).

So with reduced pressure less oxygen gets bound into the blood and is available to the muscles. The body responds to this hypoxia by releasing hormones, one of which is erythropoietin (not to be confused with the sythentic version of EPO loved by drug cheats). The natural EPO stimulates production of red blood cells and over time you get more mature cells for the oxygen to bind to and running at altitude becomes easier. And of course when you return to sea level and normal partial pressure you have those extra cells which can transport more oxygen to the muscles and hey presto you can run faster. At least thats the idea.

An easy way to think about it is transporting goods on the motorway. If you want to move more stuff you can add an extra lane to the motorway, or make bigger lorries or put more lorries on the motorway moving closer together. The effect of altitude training is basically the last option ! And if you are thinking "surely too many lorries equals a traffic jam" you would be right. Abuse EPO and your blood can get too thick, the arteries grind to a halt and cardiac arrest can follow. However training at altitude is safe, your body regulates the production blood cells to a healthy level.

Many sea level athletes have had problems with anaemia at altitude as their iron stores quickly get used up in the body's rush to create new blood cells so for 3 weeks before going to altitude I take iron supplements to make sure that my stores are fully topped up. Waiting until arriving at 8000ft is too late !

The other advantage to training in a place like Kenya is that for a few weeks you can be totally focused on training and recovering in the company of top class athletes with near perfect weather conditions. This inevitably means that you train harder than you would back at home. So its also important before going away to make sure that any niggling injuries or misaligned joints are taken care of before going away which I did earlier in the week.

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