Understanding Altitude Sickness
Altitude sickness arises from the body’s response to high elevations and is characterized by hypoxia (insufficient oxygen in the blood, brain, or tissues), fluid accumulation in the lungs or brain, and cold and dehydration. To alleviate symptoms, descend to a lower altitude, keep warm, and maintain hydration, avoiding alcohol during hikes.
Understanding the Causes of Altitude Sickness
At sea level, dry air is composed of 20.9% oxygen. As altitude increases, air becomes less dense (expands due to lower atmospheric pressure), reducing the percentage of oxygen available. For instance, at 5,500 meters, the oxygen level is about 50% of that at sea level, and only 30% at the summit of Everest.
The body can typically adapt to these changes, but this process needs to be facilitated. Altitude sickness often starts above 2,500 meters. It’s recommended to limit ascension to no more than 300 meters per day above 3,000 meters and to “climb high, sleep low.”
Acclimatization is crucial, especially for those who start fast and feel fit initially, as they may face more issues at higher altitudes. Starting with a slow, steady pace aids in bodily adjustment and lowers the risk of complications. This is particularly important for treks starting at high altitudes, like those from Lukla in Everest, which begin at 2,600 meters. Rest days at 3,000 and 4,000 meters are beneficial.
Types and Symptoms of Altitude Sickness and Their Treatments
1. Acute Mountain Sickness (AMS)
AMS manifests through headaches, dizziness, fatigue, shortness of breath, loss of appetite, stomach aches, and sleep difficulties, worsening at night due to decreased breathing rates.
Treatment: Headache tablets and Diamox, a diuretic that increases breathing rate and aids in fluid removal, can alleviate symptoms. If symptoms persist, descend at least 200 meters and rest, descending further if necessary. [Consider starting Diamox before reaching 3,000 meters.]
2. High-Altitude Pulmonary Edema (HAPE)
HAPE involves dangerous fluid accumulation in the lungs, hindering air absorption and oxygen distribution.
Symptoms: Breathlessness at rest, an elevated heart rate, coughing with white or pink sputum, and blue lips, typically appearing after two or three days at altitude.
Treatment: Immediate descent to a lower altitude for increased oxygen and air pressure, and seek medical attention. HAPE can be life-threatening within hours.
3. High Altitude Cerebral Edema (HACE)
HACE is a severe fluid buildup in the brain, leading to irrational behavior, confusion, inability to walk straight, severe headaches, nausea, vomiting, lethargy, and potentially coma.
Treatment: Provide oxygen or rapidly descend to a lower altitude. HACE can be fatal within hours.
HAPE and HACE can co-occur and affect approximately 1% of trekkers between 4,000 and 5,000 meters. Not experiencing AMS previously does not guarantee immunity on subsequent treks.
Pay attention to your body’s signals, and inform your guide and fellow trekkers of any unusual symptoms. Prioritize health and safety over a “macho attitude” to ensure a memorable and safe trekking experience.
Duration: 
