When trekking in the Himalayas, it’s important to understand altitude sickness. There are three main forms:
1) Acute Mountain Sickness (AMS)
AMS is a mild illness that can affect trekkers, hikers, and climbers above 2,500 meters. It feels similar to a hangover and is caused by reduced air pressure and lower oxygen levels. The faster you ascend, the greater the risk.
Symptoms:
- Difficulty sleeping
- Dizziness or light-headedness
- Fatigue
- Headache
- Loss of appetite
- Nausea or vomiting
- Rapid pulse
- Shortness of breath with exertion
Prevention:
- Descend immediately if symptoms worsen (at least 1,000m, even at night).
- Drink plenty of fluids and avoid alcohol.
- Garlic soup is a traditional local remedy.
- Acetazolamide (Diamox) may be prescribed to ease breathing.
2) High Altitude Pulmonary Edema (HAPE)
HAPE is a dangerous condition where fluid builds up in the lungs, preventing proper oxygen intake. It can be fatal within hours if untreated.
Symptoms:
- Fast heart rate and breathlessness even at rest
- Blue lips and nails
- Elevated body temperature
- Extreme fatigue and low fever
- Coma (unresponsiveness)
- Death if untreated
Prevention:
- Descend immediately to a lower altitude.
- Drink fluids and avoid alcohol.
- Eat high‑carbohydrate foods and drink hot liquids (garlic soup is recommended).
- Provide extra oxygen or use a Gamow bag if available.
- Medicines such as Sildenafil (Viagra) or Nifedipine may be prescribed to improve lung function.
3) High Altitude Cerebral Edema (HACE)
HACE occurs when fluid builds up in the brain, causing swelling. It is life‑threatening and requires urgent action.
Symptoms:
- Severe headache, vomiting, confusion, drowsiness, loss of balance
- Irrational or bizarre behaviour
- Inability to walk in a straight line (“heel‑to‑toe” test)
- Coma (unresponsiveness)
- Death within hours if untreated
Prevention:
- Descend immediately and rapidly to a lower altitude.
- Provide extra oxygen or use a Gamow bag.
- Dexamethasone (Decadron) may be prescribed to reduce brain swelling.
Source: Altitude.org
