section_path: Mountains and humans
section_name: Mountains and humans
paragraph_text: Mountains and humans
  
  The highest known permanently tolerable altitude is at 5,950 metres (19,520 ft). At very high altitudes, the decreasing atmospheric pressure means that less oxygen is available for breathing, and there is less protection against solar radiation (UV). Above 8,000 metres (26,000 ft) elevation, there is not enough oxygen to support human life. This is sometimes referred to as the " death zone ". The summits of Mount Everest and K2 are in the death zone.