Sunday, February 22, 2009

Altitude Attitude

If you love skiing, hiking and running at high altitude, but you live at sea level like me, there are some things you should do before you go from zero feet to 12,000 feet to avoid acute mountain sickness (AMS).

AMS occurs from the combination of reduced air pressure and a lower concentration of oxygen at high altitude. Symptoms can range from mild to life-threatening, and can affect the nervous system, lungs, muscles, and heart. In most cases the symptoms are mild. In severe cases fluid collects in the lungs (pulmonary edema) causing extreme shortness of breath, which further reduces how much oxygen a person gets. Brain swelling may also occur (cerebral edema). This can cause confusion, coma, and, if untreated, death.

Approximately 20% of people will develop mild symptoms at altitudes between 6,300 to 9,700 feet, but pulmonary and cerebral edema are extremely rare at these heights. However, above 14,000 feet, a majority of people will experience at least mild symptoms. Some people who stay at this height can develop pulmonary or cerebral edema.

Symptoms generally associated with mild to moderate altitude illness include:
Difficulty sleeping
Dizziness or light-headedness
Loss of appetite
Nausea or vomiting
Rapid pulse (heart rate)
Shortness of breath with exertion

Symptoms generally associated with more severe altitude illness include:
Bluish discoloration of the skin
Chest tightness or congestion
Coughing up blood
Decreased consciousness or withdrawal from social interaction
Gray or pale complexion (cerebral edema)
Inability to walk in a straight line, or to walk at all
Shortness of breath at rest

The key to avoiding AMS is a gradual ascent that gives your body time to acclimatize. People acclimatize at different rates, so no absolute statements are possible, but in general, the following recommendations will keep most people from getting AMS:
- If possible, you should spend at least one night at an intermediate elevation below 3000 meters (10,000 feet).
- At altitudes above 3000 meters (10,000 feet), your sleeping elevation should not increase more than 300-500 meters (1000-1500 feet) per night.
- Every 1000 meters (3000 feet) you should spend a second night at the same elevation.
Remember, it's how high you sleep each night that really counts; climbers have understood this for years, and have a maxim "climb high, sleep low". The day hikes to higher elevations that you take on your "rest days" (when you spend a second night at the same altitude) help your acclimatization by exposing you to higher elevations, then you return to a lower (safer) elevation to sleep. This second night also ensures that you are fully acclimatized and ready for further ascent.

Things to Avoid
Respiratory depression (the slowing down of breathing) can be caused by various medications, and may be a problem at altitude. The following medications can do this, and should never be used by someone who has symptoms of altitude illness (these may be safe in persons who are not ill, although this remains controversial):
- Alcohol
- Sleeping pills
- Narcotic pain medications in more than modest doses

Here are the nutrition tips you should follow to make your trip more enjoyable and reduce the chances of altitude sickness:

Two days before you leave:
1. Drink plenty of fluids
2. Refrain from alcohol
3. Eat a "clean" diet - fruits, vegetables, whole grains, fish, nuts. Avoid processed foods and foods with added sugar.

On the airplane: Continue the tips listed above, particularly consuming plenty of fluids.

When you arrive:
1. Continue the tips listed above.
2. Slowly make you ascent. Everyone has a different tolerance to the change in altitude. Some people can jump right into the 12,000 foot ski bowl with no problems, while others might take a day or two to get down the intermediate run without feeling lightheaded or nauseous.
3. Have fun!!!

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