Oxygen is the "food" the body can not go without even for a few minutes. The body is adjusted to getting a certain amount of oxygen with each breath. When traveling to a higher elevation area the body undergoes adjustments in order to get the proper amount of oxygen. One such adjustment is the heart rate increasing. With an increased heart rate blood can distribute the oxygen at a faster rate. With less oxygen coming in with each breath, the oxygen must be distributed more quickly in order to continue to get sufficient oxygen. Another adjustment is taking deeper breaths. A greater lung capacity will aid the body in getting increased oxygen. It is interesting that through evolution, peoples that have lived generation after generation in high altitude areas have a greater lung capacity and a larger heart to distribute what oxygen is available in the thin air. Unfortunately, most of us don't have this genetic adaptation so we must rely on deeper breaths and a greater heart rate. If the body has trouble adapting, below is some additional information that can help.

When traveling to high elevations it is a good idea to not immediately travel to the highest elevation. Take the height increases in steps. This gives the body time to adapt better to the elevation change. For example, if you will be traveling to a 2 mile elevation, first go to a one mile elevation and take a couple of days adapting to that elevation. Altitude sickness is more likely when a person goes from a low elevation to an immediate high elevation. Another point of advice is to drink lots of water. Dehydration enhances high altitude sickness thus it is important to keep drinking water. Also be careful with how much you physically exert yourself. Altitude sickness can be enhanced by physical stress. If you will be hiking, skiing or traveling into the mountains keep in mind the preparations that should be taken when going to the high altitudes.