Many people confuse the symptoms of dehydration with altitude sickness, but at minimally to moderately high altitudes, dehydration is responsible for more illness than oxygen insufficiency.

At 6000 feet above sea level, you exhale and perspire twice as much moisture as you do at sea level. Over the course of a day, that is a lot of water, and can make a difference of a quart or more a day. At higher altitudes, it gets even more pronounced.

Higher altitude means lower air pressure. This results in more rapid evaporation of moisture from skin surface, and from your lungs. Most high altitude areas are also very low in humidity, which means evaporation is further accelerated. The combination of those two factors means that the higher up you are, the more water you need to keep your body functioning.

Toting extra water is especially important in the following conditions:

  1. If you are unaccustomed to higher altitudes.
  2. In hot weather.
  3. If you are in a desert area – most high altitude climates are dryer, but some are extremely dry.
  4. If you are engaged in strenuous activity.
  5. If you are very busy and likely to be distracted from drinking when you are thirsty.
  6. If you have health problems which require that you drink higher than normal amounts of water.

It is advisable to carry water with you wherever you go, and to make a point of drinking frequently. You may be as much as a quart low on fluids before you feel thirsty, and this effect can be magnified at high altitudes. For some reason, many people do not feel as thirsty in higher altitudes as they should, so it is important to take the extra care to drink additional fluids.

Stick to water! Coffee, tea, soda, sugary drinks, and even juice can leech additional fluids from your body. Water is the best hydration fluid there is!

If you are traveling into a new area, you may wish to bring along bottled water. Some areas at higher altitudes may not have safe drinking water in streams and creeks, and some city water systems or wells may have high mineral content which can cause digestive or circulatory problems for some individuals.

Watch for signs of dehydration:

  • Lack of perspiration
  • Dizziness
  • Shortness of breath
  • Nausea
  • Headache
  • Fatigue

Dehydration can hit suddenly, or come on slowly when you are not paying attention. Symptoms of headache, fatigue, or dizziness may appear first, and may be mistaken for altitude sickness. Sit down, and sip water – don’t guzzle it – if you feel funky.

If you are hiking, bring twice as much water as you think you would need for a lower altitude hike. This is no exaggeration, even at 6000 feet (not terribly high), a hike can demand a huge amount of water.