Acclimatization hinges on genetics. Some mountaineers can adjust to altitude in two weeks; others will never get used to it. No matter how much they train, they can’t climb high mountains without bottled oxygen. These different physical responses help explain why climbing is rife with theories about how best to acclimatize. Climbers will tell you to eat bananas, meditate, practice yoga, sleep on your left side, swallow Diamox, or avoid it and instead chew yarsagumba, a mummified caterpillar with a mushroom spore shooting from its brain.
