Understanding AMS
Acute Mountain Sickness (AMS) is caused by reduced oxygen at altitude. On Mount Kenya, symptoms typically begin above 3,500m. Point Lenana sits at 4,985m where atmospheric pressure is about 55% of sea level. AMS affects people regardless of age, fitness, or experience — there is no reliable way to predict who will be affected.
Symptoms to Watch For
Mild AMS: Headache, nausea, loss of appetite, dizziness, fatigue, and difficulty sleeping. These are common and usually manageable. Moderate AMS: Persistent vomiting, severe headache unresponsive to paracetamol, confusion, loss of coordination (ataxia). Severe AMS/HACE/HAPE: Fluid in the lungs (HAPE) or brain (HACE). These are life-threatening emergencies requiring immediate descent.
Prevention Strategies
The golden rule: climb high, sleep low. Ascend no more than 500m per day above 3,000m. Drink 3–4 litres of water per day. Avoid alcohol and sleeping pills. Eat carbohydrate-rich meals. Walk at a pace where you can comfortably hold a conversation. The Sirimon route's gradual profile is ideal for acclimatization.
Diamox (Acetazolamide)
Diamox is a prescription medication that helps prevent AMS by stimulating breathing. Typical prophylactic dose: 125mg twice daily, starting 1–2 days before ascent. Common side effects include tingling fingers and increased urination. Consult your doctor before your trip. Diamox is available at pharmacies in Nairobi and Nanyuki. It is not a cure — if symptoms are severe, the only treatment is descent.
Written by James Mwangi
Lead Mountain Guide & Founder
James Mwangi is a KWS-licensed mountain guide with over 15 years of experience leading treks on Mount Kenya. Born and raised in Nanyuki at the foot of the mountain, he has summited Point Lenana over 300 times and guided climbers from 40+ countries. He holds Wilderness First Aid (WFA) certification and is a certified Leave No Trace trainer.
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