At high elevations, low air pressure makes the air "thin." In other words, there's less oxygen available to breath in any given space.
Without oxygen masks, acute mountain sickness can cause decreased consciousness, interfering with judgment.
Acute mountain sickness causes lethargy and shortness of breath. Decreased physical ability hinders safe and timely mountain travel.
High-altitude pulmonary edema (HAPE) is a life-threatening condition resulting in fluid buildup in the lungs. Lack of oxygen at high elevation can cause HAPE.
High-altitude cerebral edema (HACE) is a potentially fatal condition where fluid builds up in the brain as a result of oxygen deficiency.
Article Written By Kathrine Cole
Kathrine Cole is a professional outdoor educator. She teaches rock climbing, backpacking, cycling, and bike maintenance classes. She is a graduate of the National Outdoor Leadership School, a Wilderness First Responder, and a Leave No Trace Trainer.