What is Acute Mountain Sickness?

Acute Mountain Sickness (AMS) is a common condition that occurs when the body fails to adapt to lower oxygen levels at high altitudes. It typically affects trekkers, climbers, and travelers ascending above 2,500 meters (8,200 feet) too quickly without proper acclimatization.

If left untreated, AMS can escalate into High-Altitude Pulmonary Edema (HAPE) or High-Altitude Cerebral Edema (HACE)—both life-threatening conditions requiring immediate descent and medical attention.

Causes of AMS

AMS occurs due to low oxygen levels (hypoxia) at high altitudes. Factors that increase the risk include:

• Rapid ascent without proper acclimatization
• Overexertion during the climb
• Dehydration and poor nutrition
• Individual susceptibility (some people are more prone than others)
• Sleeping at high altitudes without gradual adjustment

Symptoms of AMS

Symptoms typically appear 6 to 24 hours after reaching high altitude and can range from mild to severe:

Mild AMS (Common Symptoms)

✅ Headache
✅ Nausea and dizziness
✅ Loss of appetite
✅ Fatigue and weakness
✅ Shortness of breath during exertion
✅ Disturbed sleep

Moderate AMS (Worsening Symptoms)

⚠ Persistent headache, unrelieved by medication
⚠ Severe nausea and vomiting
⚠ Increased dizziness and difficulty walking
⚠ Shortness of breath at rest

Severe AMS (Life-Threatening)

🚨 Confusion and loss of coordination (signs of HACE)
🚨 Shortness of breath even while resting (signs of HAPE)
🚨 Blue or gray skin, coughing up pink frothy fluid (HAPE)
🚨 Inability to walk or stay conscious (HACE)

If severe symptoms develop, immediate descent is critical to prevent fatal complications.

Prevention of AMS

The best way to prevent AMS is to ascend gradually and allow your body to acclimatize. Follow these essential tips:

✅ Gradual Ascent: Do not ascend more than 500m (1,640 ft) per day once above 3,000m (9,800 ft).
✅ Acclimatization Days: Take rest days at higher altitudes (e.g., in places like Namche Bazaar, Dingboche, or Kyanjin Gompa).
✅ Stay Hydrated: Drink at least 3-4 liters of water daily.
✅ Eat High-Carbohydrate Meals: Your body needs more energy at altitude.
✅ Avoid Alcohol & Smoking: Both can worsen dehydration and AMS symptoms.
✅ Medications:

• Acetazolamide (Diamox): Helps prevent AMS but should be taken under medical advice.
• Ibuprofen or Paracetamol: For headache relief.
  ✅ Listen to Your Body: If symptoms appear, rest or descend. Never ignore worsening AMS.

Treatment of AMS

Mild cases of AMS can improve with rest, hydration, and medication, but if symptoms worsen:
🚑 Descend Immediately to a lower altitude (at least 500m/1,640ft).
🚑 Oxygen Therapy: Supplemental oxygen can help in emergencies.
🚑 Portable Hyperbaric Chamber: Used in extreme cases where descent is not possible immediately.

Final Thoughts

AMS is preventable and treatable, but ignoring symptoms can be fatal. If you’re trekking or climbing in Nepal—whether it’s to Everest Base Camp, Annapurna, Langtang, or Mera Peak—always follow proper acclimatization guidelines. Listen to your body, be cautious, and enjoy your adventure safely!