Altitude sickness, also known as acute mountain sickness (AMS), occurs when the body struggles to adapt to reduced oxygen levels at higher elevations. It typically begins above 2,500 meters (8,200 feet) and is common on high-altitude treks like the Everest Base Camp (EBC) trek and the Annapurna Base Camp (ABC) trek.
Symptoms range from mild headaches, dizziness, and nausea to severe cases of high-altitude pulmonary edema (HAPE) or high-altitude cerebral edema (HACE), which can be life-threatening. Understanding how to prevent altitude sickness is crucial for a safe and enjoyable trekking experience.
1. Acclimatize Properly
Gradual ascent is the most effective way to prevent altitude sickness. Treks like the Everest Base Camp Trek include acclimatization days in Namche Bazaar and Dingboche, allowing the body to adjust. Skipping these rest days increases the risk of AMS. A good rule is to avoid ascending more than 500 meters (1,640 feet) per day once above 3,000 meters (9,800 feet).
2. Stay Hydrated
Dehydration can worsen altitude sickness, so it is essential to drink plenty of water. Trekkers should aim for at least 3-4 liters of fluids per day. Herbal teas and soups available in teahouses along the EBC and ABC trails help maintain hydration. Avoiding alcohol and caffeine, which can contribute to dehydration, is also important.
3. Maintain a Slow and Steady Pace
Rushing to higher altitudes increases the likelihood of altitude sickness. Trekkers should walk at a slow and steady pace, allowing their bodies to adjust naturally. On trails like the Annapurna Base Camp Trek, where there are steep ascents, taking breaks and maintaining a steady rhythm can prevent overexertion.
4. Eat a High-Carbohydrate Diet
A diet rich in carbohydrates provides the necessary energy for high-altitude trekking. Foods like dal bhat (lentil soup with rice), pasta, and porridge are common in teahouses and help maintain stamina. Avoiding heavy, greasy foods reduces the risk of digestive issues, which can worsen altitude sickness symptoms.
5. Consider Taking Acetazolamide (Diamox)
Acetazolamide, commonly known as Diamox, helps the body acclimatize faster by improving oxygen absorption. Many trekkers use it as a preventive measure on high-altitude routes like the EBC trek. However, it should be taken only after consulting a doctor, as it can cause mild side effects such as tingling sensations in the hands and feet.
6. Avoid Sleeping at High Altitudes Too Quickly
Following the “climb high, sleep low” principle helps minimize altitude sickness. Trekkers ascending to places like Everest Base Camp should avoid sleeping at the highest point of the day’s trek. For instance, after reaching Kala Patthar for sunrise views, it is best to descend to lower elevations to sleep.
7. Recognize Early Symptoms and Act Quickly
Ignoring mild altitude sickness symptoms can lead to severe conditions like HAPE or HACE. If symptoms such as persistent headaches, dizziness, or nausea appear, the best approach is to stop ascending and rest. If symptoms worsen, descending at least 300-500 meters (1,000-1,600 feet) is necessary.
8. Avoid Alcohol and Smoking
Alcohol and smoking reduce oxygen levels in the blood, making altitude sickness worse. Many trekkers celebrate reaching Namche Bazaar, a major stop on the EBC trek, with a drink, but alcohol should be avoided at high altitudes. Smoking can also impair lung function, increasing the risk of breathing difficulties.
9. Dress in Layers to Stay Warm
Cold weather can contribute to dehydration and exhaustion, increasing susceptibility to altitude sickness. Wearing layers allows trekkers to regulate body temperature effectively. On treks like ABC and EBC, temperatures drop significantly at higher elevations, so having proper thermal clothing is essential.
10. Use Supplemental Oxygen in Emergencies
In severe cases, supplemental oxygen can be a lifesaver. Some trekking agencies provide portable oxygen cylinders for emergencies. On high-altitude treks, helicopter evacuations are available if AMS symptoms become critical. However, early prevention and proper acclimatization remain the best strategies to avoid the need for emergency oxygen.
Conclusion
Preventing altitude sickness requires proper acclimatization, hydration, a slow ascent, and listening to the body. Trekkers heading to Everest Base Camp or Annapurna Base Camp should follow these preventive measures to ensure a safe and rewarding experience. Understanding the risks and taking precautions helps make high-altitude trekking more enjoyable and less risky.
