Living in the quiet solitude and exhilarating landscape of mountainous regions can be a wonderful experience. However, there are many effects that living at high altitudes has on the human body, and while some of the effects are relatively minor, others can be very dangerous.

The air at higher altitude regions of the planet contain a much smaller amount of oxygen than sea level regions. This lack of oxygen can have numerous health effects on people who are not yet accustomed to the significant difference in altitude. Different people, however, will notice these effects at different heights. Some people who are young and healthy might not be affected by the altitude and the lack of oxygen until they elevate to around 6,000 feet above sea level, while other people who are ill, suffering from health problems or are out of shape can notice the effects at around 4,000 feet.

People living at high altitudes can suffer from altitude sickness. The oxygen content in the air decreases as the altitude increases, and thus people unaccustomed to living at high altitudes generally have trouble breathing and obtaining a sufficient amount of oxygen. For instance, at 14,000 feet a person can only inhale 60 percent of the oxygen in one breath that they would in one breath at sea level. The inability of the body to effectively and efficiently acquire constant supplies of oxygen can cause oxygen deficiency, and exercising or exerting physical activity at high altitudes can further increase the risks of oxygen deficiency. Oxygen deficiency, also referred to as hypoxia, can have detrimental effects on a person's lungs and brain, resulting in "altitude sickness." The symptoms of altitude sickness include intense nausea, throbbing headaches or severe weakness of the body.

Extreme physical weakness is another effect that can be caused by high altitudes. Muscles in the human body are accustomed to receiving an adequate amount of oxygen at all times, and thus the sudden lack of oxygen associated with mountainous regions can dramatically impair muscles. Free radicals are highly reactive molecules with unpaired electrons, and insufficient supplies of oxygen can enable free radicals to build up and accumulate like toxins within muscle tissue when cellular respiration is inhibited. As a result, people adjusting to living at high altitudes might suffer from severe fatigue in which the body, limbs and muscles become weak and depleted of energy. However, with time the body usually can successfully adapt to the new environment, and the symptoms of physical weakness eventually subside.

People not yet adjusted to the mountains commonly notice the impact of dehydration. At high altitudes people exhale and perspire twice as much moisture as they do at sea level. Thus, throughout the day a person at high altitudes loses water at a much quicker rate than his body is used to -- often the total can amount to more than an extra quart a day -- and as a result the body can become dehydrated. People not yet accustomed to high altitudes should drink extra amounts of water to prevent dehydration.