A new medical study by researchers at Miguel Servet University Hospital in Zaragoza, Spain, have discovered a previously unknown danger to high altitude mountaineering. Every mountaineer knows the risk of climbing at altitude – the lack of oxygen, the changeable weather or the lack of an easy escape that over the years has taken the life of many climbers. Now it seems that those who do return from their objective unscathed in body may have subjected their brain to unseen damage. The research studied 35 climbers from 4 expeditions who had all eschewed the use of supplemental oxygen. The 4 expeditions went to Everest, Mt Blanc, Kilimanjaro and Aconcagua. All of the test subjects received MRI scans of the brain on their return with only 1 out of the 35 returning WITHOUT measurable brain damage. You can read a more detailed report including a link to the full research at Alpinist.com>> The high level of damage is quite amazing considering how two of the mountains, Mt Blanc & Kilmanjaro, are regularly seen as easy objectives for regular climbers. In the summer of 2007, a British expedition (that was followed by a documentary crew from the BBC Horizon team) undertook a research study into the effects of low oxygen levels and human performance at extreme altitude. Their results into their research should be released next year. Source: Alpinist