Altitude Sickness

What is Altitude Sickness ?

Altitude sickness occurs when the body fails to acclimate properly to high altitudes, leading to insufficient oxygen intake. At higher elevations, although the oxygen concentration in the air remains the same, the atmospheric pressure decreases, making it harder for the lungs to absorb the necessary oxygen.

Types of Altitude Sickness

• Acute Mountain Sickness (AMS): The most common type, affecting about 65% of travellers. Symptoms include headache, fatigue, loss of appetite, nausea, sleep disturbances, shortness of breath, and dizziness. Typically appears 6-10 hours after ascent and resolves within 1-3 days with rest.

• High Altitude Cerebral Oedema (HACE): A severe condition that may develop if AMS is left untreated, affecting 10% of individuals. Symptoms include lethargy, confusion, and ataxia, usually occurring at least 2 days after ascent.

• High Altitude Pulmonary Oedema (HAPE): A life-threatening condition that can develop without prior AMS symptoms. Symptoms include shortness of breath during exertion, a dry cough, and possibly blood-stained sputum, usually occurring at least 2 days after ascent.

Prevention of Altitude Sickness

• Acclimatise Slowly: Ascend gradually and allow rest days every 3 days.
• Monitor Symptoms: Be aware of AMS symptoms and avoid sleeping more than 300 meters higher than the previous night if symptoms are present.
• Hydration and Rest: Drink plenty of fluids and minimise physical exertion.
• Medication: Consider taking Acetazolamide (Diamox) to aid in acclimatisation. Diamox helps prevent blood acidosis and stimulates breathing.

Treatment of Altitude Sickness

• AMS: Rest and take analgesics for headaches and antiemetics for nausea. If symptoms worsen, descend immediately by at least 500-1000 meters.

• HACE/HAPE: Immediate descent is crucial. Administer oxygen and medications like Nifedipine and Dexamethasone for HAPE, and Dexamethasone for HACE.

Pre-existing Medical Conditions & Altitude

Travellers with pre-existing conditions such as pulmonary issues (e.g., COPD), cardiac disease, or pregnancy should consult a GP before traveling to high altitudes, as these conditions increase the risk of altitude-related problems.

For further guidance and to obtain medications like Diamox, book a consultation with one of our expert travel clinicians. If you’ve experienced AMS on a previous trip, you’re more likely to experience it again, regardless of previous tolerance, age, or fitness level.