Science Questions

Is there a way that I can train myself in advance to avoid the risk of altitude sickness? I'm going to Tibet early in the year and I don't know how my body is going to react. Marlice in Switzerland

When you go up a mountain, there's less oxygen, and because there's less oxygen your body recognises this and starts to breathe a lot harder, so your rate of breathing goes up. Whilst this does increase the amount of oxygen in the blood, it decreases the amount of carbon dioxide stored in the blood. Carbon dioxide is a weak acid, and what this does is make your blood more alkaline, which is what makes you feel unwell. So that's why hyperventilating makes you feel dizzy because you lose carbon dioxide. There's a drug called acetazolamide, which is a carbonic anhydride inhibitor. How that works is that it stops your body converting the stored acid back into carbon dioxide, so it keeps your blood a little bit more acidic and you feel better. People in the Andes swear by cocaine or coca tea.

January 2007