High Altitude Illness in Ski Resorts (Short Version).
For the longer version, click here.
The Arizona Snowbowl is having a great season with many visitors from lower elevations. If you are a visitor to the Flagstaff area and are experiencing headache and/or nausea you may have Acute Mountain Sickness (AMS). Acute Mountain Sickness is a syndrome of headache and one or more of the following symptoms: nausea, anorexia, lightheadedness, insomnia and fatigue and occasionally vomiting. These symptoms occur after an ascent to an altitude greater than 6500 ft and more typically above 8125 ft. The symptoms can occur within one hour of ascent, but can take as long as 6-10 hours to appear. A study done in Summit County Colorado showed an incidence of acute mountain sickness of 22% at altitudes between 7000-9000 feet and 42% at altitudes of 10000 ft. The lift at the Snowbowl takes you to 11,500 ft.
The mechanism of AMS is not completely understood. One of the theories is that mild cerebral edema develops secondary to hypoxia from lower concentrations of oxygen at higher altitudes.
There are ways to prevent acute mountain sickness. Rapid acclimatization takes place over a period of three days so if you can wait three days to go up to the resort, your chances are better. It is better to proceed higher during the day and return to a lower elevation to sleep. This makes Flagstaff a little better than some of the Colorado resorts because Flagstaff sits at bout 7000 ft whereas many of the Colorado resort base locations are in the 8000ft to 9500 ft range. Overexertion can cause the onset of AMS, so take it easy at high altitudes, above 9000 ft. Avoid getting out of breath. Almost all of the studies have shown that physical fitness has no effect on preventing AMS. I believe it is better to be in shape simply because you don't have to exert as much which should theoretically reduce your incidence of AMS. The Wilderness Medical Society also recommends the following: Starting a diet of at least 70% carbohydrates one to two days prior to ascent has been shown to reduce symptoms of AMS by 30%. Proper hydration can reduce the onset of AMS. These last two recommendations are not supported by the literature as helping to prevent AMS; however, their effects are to increase endurance during exercise. They indirectly lower the incidence of AMS by making it so you don't get tired as fast or over exert too soon. Living at high altitude 7000 ft or above also serves to increase high altitude tolerance simply because your starting point on any journey is higher and you have had a long time to acclimate to your dwelling altitude.
It is important to prevent or reduce the incidence of AMS mainly because it detracts from your fun. Also AMS can progress to worse conditions as seen below. There are actually three syndromes that encompass the diagnosis of High Altitude Illness. Acute Mountain sickness is the most common. The other syndromes of HACE (High Altitude Cerebral Edema) and HAPE (High Altitude Pulmonary Edema) are much less common. HACE is the endpoint of AMS and presents with symptoms of ataxia (loss of coordination to walk), altered conscientiousness or both and is caused by swelling of the brain leading to coma and death secondary to brain herniation. HAPE is caused by fluid building up in the lungs and is manifested early on by a dry cough and decreased performance. It usually occurs the second night at a new altitude and rarely strikes after the fourth day at a new altitude due to the body's ability to adapt. HAPE accounts for most of the deaths from High Altitude Illness. Fortunately the incidence of both is low reported from 0.1-4%.
If you suspect that someone has AMS, either descend 1500 to 2000 ft or more or stop and rest. Stay hydrated. Often at higher altitudes with exertion you lose more fluid than you think. When you begin to proceed again, go at a slower pace. If the symptoms persist descend to a lower altitude. For more severe symptoms or for HACE or HAPE evacuate and seek immediate medical attention.
Much of the literature cites the use of various medications for both treatment and prophylaxis of AMS. One of the more commonly used is acetazolamide. I personally don't like to take any medications and would rather change my environment, descend if needed or rest more as any medication you take can have side effects. If you are considering medications be sure to consult a doctor first. Keep in mind that this article does not take the place of a doctor's visit or a call for help to the ski patrol who are well trained in these syndromes. For more detailed information visit hospitalprivileges.net where I have some of my favorite references posted for detailed articles on this subject. I also have posted my own experiences with AMS as well as my son's, the circumstances and what we did for treatment on my web site.