Altitude sickness is caused by rapid or prolonged exposure to low amounts of oxygen at high elevation. Symptoms may include headaches, vomiting, tiredness, trouble sleeping, blue lips and extremities and dizziness. It can progress to worse conditions including HAPE (high altitude pulmonary edema), which is a fluid buildup in the lungs that prevents the normal absorption of oxygen from the intake of air. The condition is characterized by shortness of breath (even while resting) and a feeling that you are suffocating.
Your likelihood of developing altitude sickness is dependent on a number of factors including elevation. Living in Aspen at 8000 feet elevation, I hear frequently that it usually occurs above 8000 feet, and indeed about one in five people experience some discomfort upon landing in Aspen from sea level. Being physically fit does not reduce the risk.
Headaches are the most common symptom, although headaches are also a symptom of dehydration. If in addition to headaches there is loss of appetite, nausea, excessive gaseousness, nosebleeds, and obvious shortness of breath, then it is more likely altitude, but drinking more water can’t hurt. One of the best treatments on an uphill hike is to reverse direction and descend while drinking lots of water. If descent is not immediately possible, breathing oxygen helps—but on normal hikes who has oxygen?
If the condition is mild, the symptoms typically lessen in a day or two as the person acclimatizes to the altitude. If the symptoms worsen it is certainly best to check into a medical facility. Coughing and a gray, pale or bluish skin tone can indicate an emergency.
I had an experience with altitude sickness on my 53rd fourteener climb after eight years of regularly summiting at over 14,000 feet. It happened when I backpacked to a lake and camped at over 11,000 feet to start a climb early the next morning.
The climb the next day was especially arduous, but I made it to the summit of Windom Peak in the Needle Mountain range of the Rockies, feeling pretty good.
We then descended to camp by late afternoon. Our plan was to overnight a second night still at 11,000 feet and hike out the next morning. But at four in the morning, I woke up my buddy and declared we had to get to lower altitude. I was having trouble breathing but getting along by sucking on an emergency inhaler I always have on a high-altitude climb. My lungs were full of fluid.
It was a tough situation because the only way out was to backpack 6 ½ miles and 2500 feet down to a narrow-gauge railroad track and wait for a once per day, 100-year-old steam locomotive train to come by and pick us up to get back to our car. We made it down to the tracks at 8500 feet, onto the train and back to our car, but I was still in trouble. We drove four hours back to Aspen where I checked into the hospital emergency room immediately. My oxygen saturation was at 82, not good. I was subjected to several procedures that successfully cleared my lungs; fortunately, I had not progressed all the way to HAPE. A few hours later I was in much better shape and was sent home.
To this day I don’t know why it happened on that climb and not others. Two weeks later, I did another high-mountain climb and was fine. Go figure.
The lesson I learned is that high-altitude physiology is still part mystery (some might say that about all of medicine).
My advice is to take altitude sickness seriously. It can get out of hand and can be dangerous, even life-threatening.