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Climbing the world's tallest mountains is risky business. The brave people who attempt these treks try to avoid avalanches, falling rocks, crevasses, frostbite, and dehydration. Should high altitude climbers worry about the risk of brain damage? Research conducted by scientists in Zaragoza, Spain, suggests that brain damage IS an added risk to some climbers.
The scientists examined brain scans of 35 climbers (12 professional climbers and 23 amateur climbers; 33 men and 2 women) who climbed either Mt. Everest (8,848 m; 20,030 ft), Mt. Aconcagua (6959 m; 22,832 ft), Mt. Blanc (4,810 m; 15,782 ft) or Mt. Kilimanjaro (5,895 m; 19,341 ft). Each climb was made without extra oxygen.
Within 7 to 15 days after a climb, the researchers examined the brains of the climbers using magnetic resonance imaging (MRI). The brain scans of the climbers were compared to brain scans of 20 healthy people of similar ages (the control group).
Of the 13 climbers (12 professional, 1 amateur) who started up Mt. Everest, only three made it to the summit, three made it to 8,100 m, and seven made it to 6,500-7,500 m. Only 1 climber had a normal brain scan! The brain scans of the other climbers showed signs of damage to the cerebral cortex (8 climbers) and an enlargement of the Virchow-Robin (VR) space (11 climbers). (VR spaces surround blood vessels that enter the brain and are rarely enlarged in young people.)
All eight Mt. Aconcagua climbers showed brain damage and/or enlarged VR spaces even though only five made it to the 6,000-6,400 m level and one reached only 5,500 m. Abnormalities in the brain scans were seen three years later even though the climbers did not attempt another high altitude expedition. Climbers who trekked up Mt. Blanc and Mt. Kilimanjaro had fewer abnormal brain scans. All seven climbers made it to the top of Mt. Blanc and three had abnormal brain scans. Only one Kilimanjaro climber (three made it to the summit) had an abnormal brain scan. None of the brain scans from control subjects showed signs of brain damage and only two brain scans from these people showed enlarged VR spaces.
At high altitudes, the lack of oxygen can damage nerve cells. Also, blood vessels may leak and cause brain swelling. The risk of stroke is also higher. Mountain climbing may provide a great sense of accomplishment, but it may also come at the cost of damage to the brain. Further experiments will need to be conducted to determine if the climbers' cognitive abilities have been affected.
Copyright © 1996-2008, Eric H. Chudler, University of Washington