Altitude sickness is the most common reason climbers fail to reach Kilimanjaro's summit. Understanding how to prevent and treat it can make the difference between success and disappointment. This comprehensive guide covers everything you need to know about altitude sickness on Kilimanjaro.
What is Altitude Sickness?
Altitude sickness, also known as Acute Mountain Sickness (AMS), occurs when your body doesn't get enough oxygen at high elevations. As you climb higher, air pressure decreases and there's less oxygen available with each breath.
Key Fact
At Kilimanjaro's summit (5,895m/19,341ft), there's approximately 50% less oxygen than at sea level. Your body needs time to adapt to these conditions through a process called acclimatization.
Types of Altitude Sickness
1. Acute Mountain Sickness (AMS)
The mildest and most common form. Symptoms typically appear within 6-12 hours of reaching high altitude.
Common symptoms:
- Headache (most common symptom)
- Nausea and loss of appetite
- Fatigue and weakness
- Dizziness or lightheadedness
- Difficulty sleeping
- Shortness of breath during exertion
2. High Altitude Pulmonary Edema (HAPE)
A serious condition where fluid accumulates in the lungs. HAPE can be life-threatening if not treated immediately.
Warning signs:
- Severe shortness of breath, even at rest
- Persistent cough, possibly with pink/frothy sputum
- Chest tightness or congestion
- Extreme fatigue
- Blue lips or fingernails (cyanosis)
- Rapid heart rate
⚠️ Emergency Warning
HAPE requires immediate descent and medical attention. Do not delay if you experience these symptoms. Descend at least 1,000 meters (3,280 feet) immediately.
3. High Altitude Cerebral Edema (HACE)
The most severe form of altitude sickness, where fluid accumulates in the brain. HACE is a medical emergency.
Critical symptoms:
- Severe headache that doesn't respond to medication
- Confusion and disorientation
- Loss of coordination (ataxia)
- Difficulty walking
- Altered consciousness
- Hallucinations
- Coma (in severe cases)
Who Gets Altitude Sickness?
Altitude sickness can affect anyone, regardless of age, fitness level, or previous mountain experience. However, certain factors increase your risk:
Higher Risk Factors
- Living at low elevation (sea level)
- Rapid ascent without acclimatization
- Previous history of altitude sickness
- Certain medical conditions
- Dehydration
- Alcohol consumption
Common Misconceptions
- ❌ Being fit prevents altitude sickness
- ❌ Young people are less susceptible
- ❌ Previous successful climbs guarantee immunity
- ❌ You can "push through" symptoms
- ✅ Anyone can get altitude sickness
- ✅ Proper acclimatization is key
Prevention Strategies
1. Choose the Right Route
Route selection is crucial for acclimatization. Longer routes with gradual ascent profiles have significantly higher success rates.
| Route | Days | Success Rate | Acclimatization |
|---|---|---|---|
| Northern Circuit | 9 days | 95% | Excellent |
| Lemosho | 7-8 days | 90% | Excellent |
| Machame | 6-7 days | 85% | Good |
| Marangu | 5-6 days | 65% | Moderate |
| Umbwe | 5-6 days | 60% | Poor |
2. Follow "Climb High, Sleep Low" Principle
This golden rule of mountaineering means hiking to a higher elevation during the day, then descending to sleep at a lower altitude. This helps your body acclimatize more effectively.
Example: Machame Route Day 3
- Start: Shira Camp (3,840m)
- Climb to: Lava Tower (4,630m) - lunch stop
- Descend to: Barranco Camp (3,960m) - overnight
- Result: You climbed 790m higher but only slept 120m higher than the previous night
3. Ascend Slowly ("Pole Pole")
"Pole pole" (pronounced "po-lay po-lay") means "slowly slowly" in Swahili. Your guides will repeat this constantly, and for good reason. Slow, steady climbing allows your body to adjust to decreasing oxygen levels.
Optimal Climbing Pace
- Walk at a pace where you can hold a conversation
- If you're breathing too hard to talk, slow down
- Take regular breaks (5-10 minutes every hour)
- Don't race ahead of your group
- Summit night: extremely slow pace (2-3 hours per kilometer)
4. Stay Hydrated
Dehydration exacerbates altitude sickness symptoms. At high altitude, you lose more water through breathing and increased urination.
Hydration Guidelines
- Daily target: 3-4 liters of water
- Summit day: 4-5 liters
- Check your urine: Should be clear or light yellow
- Drink before you're thirsty: Thirst is a late sign of dehydration
- Hot drinks help: Tea, soup, hot chocolate count toward hydration
5. Eat Well, Even When You Don't Feel Like It
Loss of appetite is common at altitude, but your body needs fuel. Aim for 3,000-5,000 calories per day during the climb.
- Carbohydrates: Pasta, rice, bread, porridge - easy to digest and provide quick energy
- Snacks: Energy bars, nuts, dried fruit, chocolate - eat frequently
- Avoid: Heavy, fatty foods that are hard to digest
- Force yourself: Eat even if you're not hungry
6. Avoid Alcohol and Sleeping Pills
Both alcohol and most sleeping medications depress breathing, which is dangerous at altitude where oxygen is already limited.
Important
- No alcohol for 48 hours before starting the climb
- Absolutely no alcohol during the climb
- Avoid sleeping pills unless specifically prescribed for altitude
- Caffeine in moderation is okay (coffee, tea)
7. Consider Altitude Medication
Consult your doctor about altitude sickness prevention medications before your trip.
| Medication | Purpose | Typical Dosage |
|---|---|---|
| Diamox (Acetazolamide) | Prevention & treatment of AMS | 125-250mg twice daily |
| Dexamethasone | Emergency treatment of HACE | As prescribed by doctor |
| Nifedipine | Prevention & treatment of HAPE | As prescribed by doctor |
| Ibuprofen | Headache relief | 400-600mg as needed |
About Diamox
Diamox is the most commonly used medication for altitude sickness prevention. It works by acidifying the blood, which stimulates breathing and helps acclimatization.
Common side effects:
- Tingling in fingers, toes, and lips
- Increased urination
- Altered taste (carbonated drinks taste flat)
- Mild nausea
Important: Start taking Diamox 1-2 days before ascending to test for side effects. Do not take if you're allergic to sulfa drugs.
Treatment Strategies
Mild AMS Treatment
If you experience mild altitude sickness symptoms:
- 1. Stop ascending: Stay at your current altitude until symptoms improve (usually 24-48 hours)
- 2. Rest: Avoid strenuous activity, but don't lie down all day - light walking is beneficial
- 3. Hydrate: Drink extra water (4-5 liters per day)
- 4. Take medication: Ibuprofen for headaches, Diamox if not already taking it
- 5. Monitor symptoms: Tell your guide immediately if symptoms worsen
Moderate to Severe AMS Treatment
If symptoms are severe or worsening despite rest:
⚠️ Immediate Action Required
- 1. Descend immediately: Go down at least 500-1,000 meters (1,640-3,280 feet)
- 2. Never descend alone: Always have a guide or porter with you
- 3. Descend even at night: Don't wait until morning if symptoms are severe
- 4. Seek medical attention: Contact emergency services if available
- 5. Use supplemental oxygen: If available (most reputable operators carry oxygen)
HAPE/HACE Treatment
These are life-threatening emergencies requiring immediate action:
🚨 EMERGENCY PROTOCOL
- 1. DESCEND IMMEDIATELY - Do not delay for any reason
- 2. Administer oxygen if available
- 3. Give Dexamethasone (for HACE) or Nifedipine (for HAPE)
- 4. Use portable hyperbaric chamber (Gamow bag) if descent is delayed
- 5. Arrange helicopter evacuation if possible
- 6. Continue descending until symptoms improve significantly
Remember: Descent is the only definitive treatment. Medication and oxygen are temporary measures.
Pre-Climb Preparation
Physical Training
While fitness doesn't prevent altitude sickness, being in good shape helps you cope better with the physical demands of the climb.
Recommended Training (3-6 months before)
- Cardiovascular: Hiking, running, cycling - 3-4 times per week
- Strength: Leg exercises, core work - 2-3 times per week
- Hiking practice: Long hikes with a weighted backpack (5-8 hours)
- Altitude training: If possible, spend time at 2,500-3,500m before the climb
Medical Consultation
Visit your doctor 2-3 months before your climb to:
- Get a general health check-up
- Discuss altitude sickness prevention medications
- Review any existing medical conditions
- Update vaccinations (Yellow Fever, Hepatitis A/B, Typhoid)
- Get prescriptions for emergency medications
Acclimatization Hikes
Consider spending 2-3 days in Moshi before your climb doing acclimatization hikes:
Mount Meru (Optional)
4-day climb to 4,566m - excellent acclimatization for Kilimanjaro
- ✅ Significantly improves success rate
- ✅ Beautiful scenery
- ✅ Less crowded than Kilimanjaro
- ⏰ Requires extra 4-5 days
Day Hikes Near Moshi
- Materuni Waterfalls: 1,800m elevation
- Shira Plateau: Drive to 3,600m, short hike
- Marangu Village: Hike to 2,700m
- Benefit: Helps your body start adjusting to altitude
During the Climb: Daily Monitoring
Reputable tour operators monitor climbers' health twice daily using the Lake Louise Scoring System:
Lake Louise AMS Score
Rate each symptom from 0 (none) to 3 (severe):
- Headache
- Gastrointestinal symptoms (nausea, vomiting, loss of appetite)
- Fatigue/weakness
- Dizziness/lightheadedness
Score interpretation:
0-3: No AMS
4-6: Mild AMS
7-9: Moderate AMS (consider descent)
10+: Severe AMS (descend immediately)
Pulse Oximeter Readings
Your guide will check your oxygen saturation (SpO2) and pulse rate daily:
| Altitude | Normal SpO2 | Concerning SpO2 |
|---|---|---|
| Sea Level | 95-100% | <90% |
| 3,000m | 90-95% | <85% |
| 4,000m | 85-90% | <80% |
| 5,000m | 80-85% | <75% |
| Summit (5,895m) | 75-80% | <70% |
Summit Day: Special Considerations
Summit day is when altitude sickness risk is highest. You'll climb from around 4,600m to 5,895m, spending several hours above 5,500m.
Summit Day Tips
- Start time: Usually midnight (allows descent before afternoon weather changes)
- Pace: Extremely slow - slower than you think necessary
- Breathing: Use pressure breathing technique (exhale forcefully)
- Hydration: Drink from insulated bottles (water freezes quickly)
- Snacks: High-energy foods that won't freeze (chocolate, energy gels)
- Listen to your body: Don't push through severe symptoms
- Turn-around time: Most groups have a cut-off time (usually 7-8 AM)
When to Turn Back
Making the decision to turn back is difficult but sometimes necessary. Turn back if you experience:
- Severe headache that doesn't respond to medication
- Persistent vomiting
- Confusion or disorientation
- Loss of coordination
- Severe shortness of breath at rest
- Chest tightness or persistent cough
- SpO2 below 70%
Remember
The mountain will always be there. Your health and safety are more important than reaching the summit. About 30-40% of climbers don't make it to the top, and that's okay. Many return for a second attempt and succeed.
After the Climb: Recovery
Most altitude sickness symptoms resolve quickly once you descend. However, proper recovery is important:
Post-Climb Recovery Tips
- Rest: Take 2-3 days to recover before traveling
- Hydrate: Continue drinking plenty of water
- Eat well: Replenish calories and nutrients
- Monitor symptoms: Rare, but some symptoms can persist
- Celebrate: You've accomplished something amazing!
Frequently Asked Questions
Can I climb Kilimanjaro if I've had altitude sickness before?
Yes, but take extra precautions. Choose a longer route (8-9 days), consider taking Diamox, and be prepared to turn back if symptoms recur. Many people who experienced AMS on previous climbs succeed on subsequent attempts with better preparation.
Does physical fitness prevent altitude sickness?
No. Altitude sickness can affect anyone regardless of fitness level. However, being fit helps you cope with the physical demands of the climb and may help you recover faster if you do experience symptoms.
Should I take Diamox even if I feel fine?
This is a personal decision to discuss with your doctor. Many climbers take Diamox prophylactically (preventively) starting 1-2 days before the climb. Studies show it can reduce the incidence and severity of AMS by about 50%.
How quickly do symptoms improve after descending?
Most people feel significantly better within 12-24 hours of descending 500-1,000 meters. Mild symptoms like headache may persist for a day or two but should gradually improve. If symptoms don't improve with descent, seek medical attention.
Can children climb Kilimanjaro?
The minimum age is 10 years old. Children are at the same risk for altitude sickness as adults, but they may have difficulty communicating symptoms. Extra caution and monitoring are essential. Many operators recommend waiting until age 12-13.
What's the success rate for reaching the summit?
Overall success rates range from 45-65%, with altitude sickness being the primary reason for failure. However, success rates vary dramatically by route: 95% on the 9-day Northern Circuit vs. 60% on the 5-day Marangu route. Proper acclimatization is key.
Conclusion
Altitude sickness is a serious concern on Kilimanjaro, but with proper preparation, acclimatization, and awareness, most climbers can successfully manage it. The key factors for success are:
- ✅ Choose a longer route (7-9 days minimum)
- ✅ Ascend slowly ("pole pole")
- ✅ Stay well hydrated (3-4 liters daily)
- ✅ Eat regularly even without appetite
- ✅ Consider altitude medication (Diamox)
- ✅ Listen to your body and communicate with guides
- ✅ Be prepared to turn back if necessary
Ready to Climb Kilimanjaro?
Stay at Kilimanjaro Lodge before and after your trek. Our experienced team can connect you with reputable trekking companies that prioritize safety and proper acclimatization. We'll help you prepare for the adventure of a lifetime!
Medical Disclaimer
This guide is for informational purposes only and should not replace professional medical advice. Always consult with your doctor before attempting to climb Kilimanjaro, especially if you have pre-existing medical conditions. Altitude sickness can be life-threatening if not properly managed.