Later that evening as I headed to bed for the night, 12 hours or so after getting back, I felt myself physically wither - I started to feel a dull-but-intense headache, my joints and muscles began to ache so that I just could not find a way to lie comfortably, and I oscillated between being too hot and too cold.
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| Reinhold Messner and Peter Habeler were the first to reach Everest's 29,029ft. summit without the aid of supplemental oxygen. They took 3 months to acclimatize and summit. |
At first I thought I was coming down with the flu, but soon realized that I was coming up against something I had never experienced in all of my time spent at high altitude: altitude sickness, or more correctly, altitude illness.
According the NOLS Wilderness Medicine Handbook, altitude illness "results from insufficient oxygen in the blood (hypoxia) secondary to decreased barometric pressure at altitude."
I know that altitude-related symptoms can affect anyone who does not take time to adequately acclimatize no matter their level of physical conditioning, but since I had never experienced symptoms before and had maintained an active lifestyle during my travels, even traveling as high as 10,000ft. while in Europe, I honestly did not expect it to affect me when I returned.
In light of my recent humbling experience, this post will look at some ways that the NOLS Wilderness Medicine Institute and the non-profit group The Mountaineers recommend preventing altitude illness, with a follow up post to discuss assessing and treating altitude illness in the field.
There is no standard agreement on where "high altitude" begins, and it is equally possible to feel the effects of altitude in Denver (5,280 ft.) and on Mount Rainier (14,411 ft.), but for our purposes and based on general consensus, we will use the following labels:
- Low Altitude: sea level to 5,000ft. (1,524m)
- Intermediate Altitude: 5,000ft. to 7,000ft. (2,134m)
- High Altitude: 7,000ft. to 18,000ft. (5,486m)
- Extreme Altitude: above 18,000ft. or 5,486m
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| The Eiger seen from the Swiss town of Mürren. There is 40% less oxygen at Eiger's 13,025 foot summit than at sea level. |
Effects of altitude are rarely felt at Low Altitude and traveling to Extreme Altitudes should only be done under the supervision of experienced mountain guides, so we will limit our focus to Intermediate and High Altitudes.
According to Stephen Bezruchka, M.D., in his book Altitude Illness: Prevention & Treatment published by The Mountaineers, there is no absolute rule for avoiding altitude illness at high elevation, as it varies for each person in each instance. The key, he says, is acclimatization - giving your body time to adjust slowly to the increased physical demands that accompany traveling at higher elevation.
Dr. Bezruchka asserts in that altitude illness can almost always be avoided by making your ascent slowly and by specifically focusing on gradually raising your sleeping elevation. His advice for optimizing acclimatization - "Increase the sleeping altitude by 1000 feet (300 m) each night above 10,000 feet (3050 m). While ascending, take a break every two to three days by sleeping at the same altitude as the previous day."
Dr. Beruchka also makes a point to note that staying hydrated enough for your circulatory system to make the necessary physiological adjustments to altitude is crucial. "One recommendation is to drink sufficient water to produce at least two bursting bladders full of urine a day," he says, but warns that "people may not perceive their own bladder capacity accurately, so many experienced trip leaders recommend drinking at least four quarts (liters) of fluid a day."
Among Dr. Bezruchka's other words of advice: Eat enough food but avoid excesses of salt, do not drink alcohol while acclimatizing, some light exercise can enhance altitude adaptation (but he also warns that too much exercise can quickly lead to serious altitude illness conditions).
His final thought on the issue of acclimatization: "Behavioral characteristics may be one of the most important aspects in preventing altitude illness. Goal-oriented and driven people may be more at risk, as they will push themselves to go higher and deny symptoms of altitude illness," and warns that "peer pressure may push someone to ascend faster than she otherwise would... fixed schedules make it difficult for an individual to admit having symptoms of altitude illness for fear of slowing down the group or being left behind."
Dr. Bezruchka asserts in that altitude illness can almost always be avoided by making your ascent slowly and by specifically focusing on gradually raising your sleeping elevation. His advice for optimizing acclimatization - "Increase the sleeping altitude by 1000 feet (300 m) each night above 10,000 feet (3050 m). While ascending, take a break every two to three days by sleeping at the same altitude as the previous day."
Dr. Beruchka also makes a point to note that staying hydrated enough for your circulatory system to make the necessary physiological adjustments to altitude is crucial. "One recommendation is to drink sufficient water to produce at least two bursting bladders full of urine a day," he says, but warns that "people may not perceive their own bladder capacity accurately, so many experienced trip leaders recommend drinking at least four quarts (liters) of fluid a day."
Among Dr. Bezruchka's other words of advice: Eat enough food but avoid excesses of salt, do not drink alcohol while acclimatizing, some light exercise can enhance altitude adaptation (but he also warns that too much exercise can quickly lead to serious altitude illness conditions).
His final thought on the issue of acclimatization: "Behavioral characteristics may be one of the most important aspects in preventing altitude illness. Goal-oriented and driven people may be more at risk, as they will push themselves to go higher and deny symptoms of altitude illness," and warns that "peer pressure may push someone to ascend faster than she otherwise would... fixed schedules make it difficult for an individual to admit having symptoms of altitude illness for fear of slowing down the group or being left behind."
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