Quick Answer
Altitude sickness is the biggest risk on Kilimanjaro, but it can be managed with the right preparation. The key is to climb slowly, drink plenty of water, choose a longer route and listen to your body.
This guide explains what altitude sickness is, how to recognise the symptoms, and — most importantly — how to prevent it so you can enjoy your trek and reach the summit safely.
What Is Altitude Sickness?
Altitude sickness (also called Acute Mountain Sickness or AMS) happens when your body does not have enough time to adjust to lower oxygen levels at high altitude. It can affect anyone, regardless of fitness level, age or experience.
On Kilimanjaro, you will be climbing from around 1,800 m at the base to 5,895 m at the summit. This is a huge change in altitude, and your body needs time to adapt.
Types of Altitude Sickness
1. Mild AMS
This is the most common form and usually causes headaches, nausea, dizziness and fatigue. It is uncomfortable but manageable if you slow down and rest.
2. Moderate AMS
Symptoms become more severe — persistent headache, vomiting, weakness and difficulty sleeping. You should stop ascending and rest until symptoms improve.
3. Severe AMS (HAPE or HACE)
This is rare but serious. High Altitude Pulmonary Edema (HAPE) affects the lungs, and High Altitude Cerebral Edema (HACE) affects the brain. Both require immediate descent and medical attention.
Symptoms to Watch For
- Headache
- Nausea or vomiting
- Dizziness
- Fatigue
- Difficulty sleeping
- Loss of appetite
- Shortness of breath (at rest)
- Confusion or loss of coordination (severe cases)
How to Prevent Altitude Sickness
1. Choose a Longer Route
The best way to prevent altitude sickness is to give your body more time to acclimatise. Routes like Lemosho (7–8 days) and Northern Circuit (8–9 days) have higher summit success rates because of their gradual ascent. [625][627][628]
2. Climb Slowly (“Pole Pole”)
“Pole pole” means “slowly” in Swahili — and it is the golden rule on Kilimanjaro. Walk at a steady, comfortable pace and do not rush.
3. Drink Plenty of Water
Dehydration makes altitude sickness worse. Aim for 3–4 litres of water per day.
4. Eat Well
Even if you do not feel hungry, eat regular meals to keep your energy up.
5. Avoid Alcohol and Smoking
Both can worsen altitude sickness and interfere with acclimatisation.
6. Consider Medication
Some climbers use Diamox (acetazolamide) to help with acclimatisation. Always consult your doctor before taking any medication.
7. Listen to Your Body
If you feel unwell, tell your guide immediately. Do not try to “push through” symptoms.
What to Do If Symptoms Appear
- Stop ascending and rest
- Drink water and eat something
- Inform your guide
- If symptoms worsen, descend immediately
- Seek medical attention if severe symptoms appear
When to Descend
Descend immediately if you experience:
- Severe or worsening headache
- Persistent vomiting
- Confusion or loss of coordination
- Shortness of breath at rest
- Any signs of HAPE or HACE
Frequently Asked Questions
Can altitude sickness be prevented?
Yes — with slow ascent, hydration, a longer route and listening to your body, you can reduce the risk significantly. [625][627]
Does fitness prevent altitude sickness?
No — fitness helps you enjoy the trek, but it does not prevent altitude sickness.
What is the best route to avoid altitude sickness?
Lemosho (7–8 days) and Northern Circuit (8–9 days) have the best acclimatisation profiles. [625][627][628]
Should I take Diamox?
Some climbers use it, but always consult your doctor first.
How much water should I drink?
Aim for 3–4 litres per day.
What should I do if I feel unwell?
Stop ascending, rest, drink water and inform your guide.
When should I descend?
Immediately if you have severe or worsening symptoms, especially confusion or shortness of breath at rest.
Can I still summit if I get mild AMS?
Yes — mild AMS is common and manageable if you slow down and rest.