Altitude sickness is the single biggest threat to your Kilimanjaro summit attempt. It affects roughly 70% of climbers who do not reach the top, and it can affect anyone regardless of age, fitness, or experience. The good news: with proper preparation, you can significantly reduce your risk.
Key Fact
Altitude sickness is not about fitness. Very fit athletes sometimes get it because they push too hard. The key is patience and proper acclimatization.
What Is Altitude Sickness?
Altitude sickness (Acute Mountain Sickness or AMS) occurs when you ascend faster than your body can acclimatise. At sea level, air contains 21% oxygen. At Kilimanjaro's summit (5,895m), there is roughly half the oxygen. Your body needs days to produce additional red blood cells — which is why acclimatization is critical.
Symptoms: What to Watch For
⚠️ Mild AMS
- Headache — throbbing pain
- Nausea or loss of appetite
- Fatigue and weakness
- Dizziness
- Difficulty sleeping
- Mild shortness of breath
🔶 Moderate AMS
- Severe headache (not relieved by ibuprofen)
- Persistent nausea and vomiting
- Extreme fatigue — unable to walk
- Shortness of breath at rest
- Decreased coordination
🚨 Severe AMS (HACE/HAPE)
- Confusion or disorientation
- Inability to walk straight
- Severe breathlessness at rest
- Coughing pink/frothy sputum
- Gray or pale skin
- Loss of consciousness
⚠️ When to Descend Immediately
If you experience any symptoms of moderate or severe AMS, you must descend immediately. Do not wait to see if symptoms improve. Descending 500–1,000 metres can provide rapid relief. Our guides carry pulse oximeters and conduct regular health checks.
Risk Factors
Speed of Ascent
Climbing too fast is the #1 cause of AMS. "Pole pole" (slowly, slowly) is not just a saying — it's a survival strategy.
Final Altitude
The higher you go, the greater the risk. Most AMS symptoms appear above 3,500 metres.
Individual Susceptibility
Some people are more prone to AMS than others. There is no way to predict this. Fitness does NOT correlate with risk.
Dehydration
Dry air at altitude causes rapid fluid loss, worsening altitude symptoms.
Overexertion
Pushing too hard increases oxygen demand and can trigger or worsen AMS.
Poor Nutrition
Your body burns 50% more calories at altitude. Undereating weakens your ability to adapt.
Prevention Strategies That Work
Choose a Route with Enough Days
Longer routes give your body more time to adapt. 7+ days is strongly recommended for first-timers.
Climb High, Sleep Low
Ascend to higher altitude during the day, descend to sleep. This is the gold standard for acclimatization.
Walk Slowly — Pole Pole
You should be able to hold a conversation while walking. If you cannot, slow down.
Stay Hydrated
Drink 3–4 litres per day. Monitor urine colour — pale yellow is normal, dark means dehydration.
Eat Enough Food
Your body burns 50% more calories at altitude. Force yourself to eat even when appetite is low.
Avoid Alcohol & Sleeping Pills
Both suppress respiration and interfere with acclimatization. Avoid completely during your climb.
Consider Diamox
Acetazolamide helps prevent AMS by stimulating breathing. Consult your doctor before your climb.
Report Symptoms Immediately
Never ascend with AMS symptoms. Rest or descend. Your guide will help you decide.
Route Choice and AMS Risk
| Route | Days | Success Rate | AMS Risk |
|---|---|---|---|
| Northern Circuit | 9 | 97% | Very Low |
| Lemosho | 8 | 95% | Low |
| Machame | 7 | 85% | Moderate |
| Marangu | 6 | 75% | Moderate-High |
| Marangu (5-day) | 5 | 60% | High |
Myths About Altitude Sickness
"Fit people don't get AMS"
False. Fitness has no correlation with AMS susceptibility. Very fit athletes sometimes get AMS because they push too hard.
"You can train for altitude at sea level"
False. Your body can only truly acclimatize by being at altitude. Altitude masks help but cannot replicate the real thing.
"Once you have AMS, your climb is over"
Not necessarily. Many climbers experience mild AMS, rest for a day, then continue successfully.
"Diamox is a magic pill"
It helps but does not guarantee AMS prevention. Use alongside proper acclimatization, hydration, and slow pacing.
Your AMS Prevention Checklist
- Choose a route with 7+ days for adequate acclimatization
- Walk slowly — pole pole — and rest when needed
- Drink 3–4 litres of water per day
- Eat regularly even when appetite is low
- Avoid alcohol and sleeping pills at altitude
- Consider Diamox after consulting your doctor
- Report symptoms to your guide immediately
- Never ascend with AMS symptoms — rest or descend
- Trust your guides' experience and decisions
Climb with Confidence
Every Bush Lion Tours climb is led by guides trained in high-altitude medicine, equipped with pulse oximeters and Gamow bags, and experienced in AMS management.
