Many popular resorts are 8,000 to 9,500 feet above sea level, and the mountain summits rise even higher. You may have noticed your breathing is faster or deeper, and you may feel short of breath, especially when you are active. This is the body's first and most effective response to altitude. Your heart is likely to beat faster also; this, too, is a helpful normal reaction.
However, you may also develop a headache, a touch of nausea or unusual tiredness; some people even have trouble sleeping. Depending on the altitude, 20 to 80 percent of those from near sea level have one or several symptoms, which are called acute mountain sickness or AMS. Children are slightly more susceptible. The older you are, the less likely you are to be affected, with the exception of the elderly, who are at higher risk for AMS.These symptoms usually go away in a day or two. If they grow worse, or if you are worried, consult a physician. If you develop a worsening cough, increasing shortness of breath or feel like you have fluid in your lungs, seek medical attention at once. Altitude illness, though usually minor, can become serious quite rapidly, so don't take it lightly. Studies show that those living at a modest altitude like 5,000 feet or those coming from low altitudes and spending a couple of nights at 5,000 feet have decreased symptoms when they increase altitude. At high altitudes (above 8,000 feet) take it easy for the first day or two. Eat more foods high in carbohydrates, drink more water than usual and take less salt. Diamox is a prescription drug which prevents the unpleasant symptoms for many people. Since many of Yellowstone National Park's visitors come from the Intermountain West and live at moderate altitudes, they should still know about AMS when visiting the park. Dr. Lily Conrad reported on altitude sickness in Yellowstone National Park. She worked at Lake Hospital, located within the park, which provides seasonal medical care for thousands of park visitors and employees each year. At 7,733 feet, Yellowstone Park and Lake Hospital are at moderately high altitude. The highest road elevation within Yellowstone is 8,859 feet at the top of Dunraven Pass. Entry into the park from the south, east or north requires crossing passes of 7,988 to 10,960 feet. About 3 million visitors go through Yellowstone yearly, from all parts of the world, most from lower altitudes and many from sea level. Tour buses bring elderly passengers with a spectrum of medical problems. The Lake Hospital saw "mild altitude sickness" both in visitors and in seasonal park employees, who also come from all areas of the United States. Park employees with AMS are seen in the first six weeks of the season. The cases of AMS in park employees declines to zero after early June as they become acclimatized. Mild or acute mountain sickness represents a frequent problem for Yellowstone National Park visitors. Even moderate elevations such as those in the park can present a significant challenge to visitors from lower altitude.