Several times a year I will be asked by patients about travel to a part of the country or the world where they may experience a period of exposure to high altitudes. The concern these patient have is based on the fact that they usually have lung disease of some significance and want to know how safe the high altitude experience may be for them. The number of unacclimatized lowlanders with medical conditions who travel to high altitude locations is increasing. In 1992 only 10% of the trekkers in Nepal where over 50 years of age, and a more recent survey found 47% were over 50 years of age and 155 were over the age of 60. Travelers to high altitude areas are often on multiple, long term medications. Diseases present in these travelers include asthma, COPD, hypertension, diabetes, thyroid disease and inflammatory bowel disease, along with a smattering of more unusual problems.
As a physician trained in Undersea and Hyperbaric Medicine, I occasionally get referrals from patients and physicians about advice on high altitude travel plans. The most important variable in these circumstances is the reduction in barometric pressure at high altitude which reduces the amount of oxygen in the air you are breathing. Although the risk of acute altitude illness begins with an ascent above 2000 to 2500 meters (6500 to 8200 feet), some patients with chronic medical conditions are at risk at lower altitudes.
Talk to your doctor before scheduling a trip to a high altitude location