High-Altitude Travel
Success in your alpine adventures depends on proper acclimatization.

A change in altitude can cause a change in attitude” is a great saying. Still, traveling to high or moderate altitude can cause problems for many individuals. While severe altitude-related medical conditions such as high-altitude pulmonary edema (HAPE) or high-altitude cerebral edema (HACE) are uncommon, they can be fatal if untreated.

Various levels of high altitude are defined as follows:

Moderate Altitude: 4,000-10,000 feet
(Salt Lake City, Denver, Leadville)
High Altitude: 10,000-18,000 feet
(any Colorado fourteener, Mt. Whitney,
Mt. Hood)
Extreme Altitude: >18,000 feet
(Mt. McKinley, Mt. Everest)

PRE-TRIP
Prior to your trip, it is important to build your fitness level so it is appropriate for the activities you plan to do at altitude. Specializing your fitness routine for a weeklong ski trip should include a combination of strength training, balance and skills training, endurance, and—if possible—actual alpine skiing. For a backpacking or mountain climbing journey, building endurance with hiking and/or stair climbing would provide excellent activity-specific fitness. In general, a 10-12 week progressive exercise program can help increase fitness levels and endurance by 10-20 percent for most recreational athletes. Finding an experienced and certified coach, personal trainer, or fitness professional can help you make the most of your fitness training. Of course, if you have less time, then do what you can, but remember: failing to plan ahead can be a plan for failure.

FIRST FEW DAYS
The first two or three days at altitude, your body is making big adjustments. It helps a great deal if you take certain precautions. If possible, stage your ascent by starting at a lower elevation and move higher over time. Individuals who are rapidly ascending to high or extreme altitude, or those who are susceptible to AMS, are often prescribed medications to prevent altitude illness. However, these medications can have serious side effects and they are not typically prescribed as preventative medicine for high-altitude travelers. The ultimate preventative measure for reducing altitude illnesses is time. The more time that you have available to slowly ascend, the better you will feel. At elevations greater than 10,000 feet, it is recommended you only climb about 3,000 feet per day. For altitudes less than 10,000 feet, there is less of a concern as the impact of moderate altitude is considerably less stressful than high or extreme altitude.

Once you arrive at high altitude, be aware that your body is responding to a decrease in available oxygen. Oxygen is necessary to break down fuels (carbohydrates, fats, and even proteins to a small extent) into usable energy for the muscles, heart, brain, and all other organs. At the top of Mt. Everest, there is a scant one-third the oxygen available compared to sea level. At an altitude of 10,000 feet, the effective amount of oxygen available to the body is about 30 percent lower than that available at sea level.
The single most important acute response to high altitude is an increase in breathing rate. When this happens, there tends to be a slight disturbance in your body’s acid-base balance. This imbalance leads to an increase in diuresis (increased urine production), which can lead to dehydration.

Other concerns for high altitude travel include an increase in solar radiation, very low air humidity, decreased exercise capacity, and changes in energy metabolism. To effectively counter these negative effects of high altitude, try the following:
• Avoid drinking alcohol the first 1-2 days.
• Maintain hydration by drinking more water and fluids.
• Increase your carbohydrate intake.
• Sleep with a humidifier in your room if possible.
• Decrease your normal exercise intensity, especially in the first day or two.

HIGH-ALTITUDE ADAPTATIONS
Within ten days, your body will have made many of the short-term adaptations to altitude, with respiration and acid-base balance stabilization being two of the targeted adaptations. With longer altitude exposure, one of the major responses your body will experience is an increase in the number of red blood cells in your bloodstream. This allows your blood to carry more oxygen to your muscles. Another longer-term altitude-related adaptation is a change in enzyme concentrations, which allows oxygen to get to your muscles more readily. Full acclimatization to moderate altitude can be achieved in about three months for most individuals. Once returning to sea level, the benefits of an extended altitude stay (greater than three weeks) can benefit endurance exercise performance for two to four weeks.

ACCLIMATIZATION LIMITATIONS
Being acclimatized, however, does not mean that you will be capable of doing what you could do at sea level. Your performance level will still be reduced. In fact, endurance performance decreases by 2-3 percent at 5,000 feet, and you lose another 2-3 percent of performance for every 1,000 feet of altitude you gain above that.
At extreme altitude, specifically above 25,000 feet, the human body cannot adapt to the altitude and long-term stays are not possible. This is typically referred to as the “death zone” for mountaineers, because no one can survive for very long at that altitude or above.