Kilimanjaro Acclimatisation Guide: How to Reduce Altitude Sickness and Climb Smarter
Acclimatisation is the real challenge on Kilimanjaro
Many UK travellers worry most about fitness, but Kilimanjaro success is often decided by how well you acclimatise. Altitude affects everyone differently. You can be very fit and still struggle, while someone less athletic may feel fine. The difference is usually pace, itinerary, hydration, sleep, and how quickly you respond to early symptoms.Kilimanjaro rises to 5,895 metres, high enough for acute mountain sickness (AMS) to be a genuine risk. The good news is that with a sensible route choice and a disciplined approach, most people can reduce risk significantly.
What acclimatisation actually means
At higher altitudes, there’s less oxygen available with each breath. Your body needs time to adapt by changing breathing rate, heart rate, and blood chemistry. This is why “slow and steady” isn’t just a slogan—it’s the mechanism that helps you keep going.On Kilimanjaro, you gain altitude quickly compared to many other high mountains, because you start at a relatively high trailhead and climb day after day. Your itinerary and daily ascent profile matter more than how hard you can push.
Common altitude sickness symptoms to recognise early
AMS often starts with symptoms that can be mistaken for tiredness:- Headache (especially persistent or worsening)
- Nausea or reduced appetite
- Dizziness or lightheadedness
- Unusual fatigue or weakness
- Poor sleep
More serious conditions include HACE (cerebral) and HAPE (pulmonary), which are medical emergencies and require immediate descent and professional support. Warning signs can include confusion, loss of coordination, breathlessness at rest, and a persistent cough with chest tightness. Your guides should be trained to assess symptoms and act decisively—choose an operator with robust safety procedures.
The biggest acclimatisation decision: route and number of days
From the UK, it’s tempting to choose a shorter climb to reduce cost or time off work. But short itineraries often mean faster altitude gain and less time to adapt.As a general principle, choose:
- More days over fewer days
- Routes with built-in acclimatisation (for example, “climb high, sleep low” opportunities)
- An operator that will not rush the pace to meet a schedule
A longer itinerary can feel like a bigger commitment, but it often results in a more enjoyable trek, fewer headaches, and better summit chances.
Pace: the simplest, most powerful tool
Your pace should feel almost frustratingly slow on early days. Many climbers who get altitude sick later can trace it back to walking too fast when the air was thicker.A useful mindset is to focus on breathing rhythm and conversation pace. If you can speak in full sentences without gasping, you’re generally moving at a sensible rate. Let the guides set the tempo, and resist the urge to “race” other groups.
Hydration and food: consistent intake beats big efforts
At altitude, dehydration can worsen headaches and fatigue, and appetite can drop. You don’t need to force huge meals, but you do need regular intake.For more in-depth guides and related topics, be sure to check out our homepage where we cover a wide range of subjects.
Practical tips:
- Drink frequently in small amounts throughout the day
- Use electrolytes if you’re drinking a lot and feeling flat
- Eat snacks even if you don’t feel hungry
- Keep a “summit snack” you genuinely enjoy
Many UK climbers find warm drinks help them drink more consistently in cold conditions, especially in the evenings.
Sleep and temperature management
Poor sleep is common at altitude, but staying warm and comfortable improves recovery. Use a sleeping bag that matches the expected temperatures and wear dry base layers at night. Cold stress adds to fatigue, and fatigue can make altitude symptoms feel worse.Also, manage sweat during the day. Overheating early, then cooling down when you stop, is a classic way to feel miserable. Adjust layers before you’re too hot.
“Climb high, sleep low” and acclimatisation walks
Many itineraries include acclimatisation hikes where you walk higher during the day and return to a lower camp to sleep. This approach helps your body adapt without the stress of sleeping at maximum height.If your guides offer a short acclimatisation walk after reaching camp, it’s often worth doing—assuming you feel well enough and conditions are safe.
Medication and medical advice
Some climbers discuss preventative medication for altitude with a doctor before travelling. This is a personal medical decision based on your health history, the route profile, and your risk tolerance. If you’re considering it, speak to a UK medical professional well ahead of your trip.Never hide symptoms to “save” a summit attempt. The safest summit is the one you can walk away from.
What to do if you feel symptoms on the mountain
Tell your guide early. Good teams would rather manage mild symptoms proactively than deal with a crisis later.Supportive actions can include:
- Slowing the pace further
- Drinking and eating regularly
- Resting at camp
- Descending if symptoms worsen or don’t improve
Descent is the most effective treatment for altitude illness. A reputable operator will prioritise health over reaching the summit.