Brain Cells into Thin Air; April/May 2008; Scientific American Mind; by R. Douglas Fields; 2 Page(s)

In the late 1890s in a laboratory atop a 4,554-meter peak in the Monta Rosa range in the Italian Alps, physiologist Angelo Mosso made the first direct observations of the effects of high altitude on the human brain: by eye and with an apparatus he designed, Mosso peeked into the skull of a man whose brain had been partly exposed in an accident, observing changes in swelling and pulsation.

Now a similar experiment has been done with noninvasive brain imaging, and for those of us who love to climb the results are not elevating. Neurologist Nicolás Fayed and his colleagues in Zaragoza, Spain, performed MRI brain scans on 35 climbers (12 professionals and 23 amateurs) who had returned from high-altitude expeditions, including 13 who had attempted Everest. They found brain damage in virtually every Everest climber but also in many climbers of lesser peaks who returned unaware that they had injured their brain. It seems that climbers of high mountains, whether weekend warrior or seasoned professional, face returning from the high peaks with a brain that is not in the same condition it was in beforehand.