Kilimanjaro Altitude Sickness

Altitude sickness is the single biggest reason climbers do not reach the summit of Kilimanjaro. It is not caused by fitness and it cannot be trained away - it is a physiological response to thin air, and the treatment is always the same: give the body time, or give it more air.

What Altitude Sickness Is

At 5,895 m the air contains roughly half the oxygen of sea level. Your body compensates by breathing faster, which raises carbon dioxide loss and changes blood chemistry. Most people tolerate this well at moderate height. The illness begins when the body adapts too slowly to a large gain in altitude.

Symptoms and How They Develop

Symptoms typically appear within hours of a significant gain in height and worsen overnight. They usually follow a recognisable order, which is why guides track the pattern rather than a single symptom.

• Headache - the earliest and most consistent symptom, and the one that matters most.
• Fatigue, dizziness and nausea - feeling wiped out, off balance, or sick in the stomach.
• Loss of appetite and poor sleep - eating becomes effortful and sleep is disturbed.
• Breathlessness at rest - the warning sign that the body is not coping.

Acute Mountain Sickness and HACE

Most altitude illness on Kilimanjaro is acute mountain sickness: uncomfortable and unpleasant, but manageable with rest, fluids and a slower profile. A small minority develop high-altitude cerebral edema, where fluid accumulates in the brain. It is rare, it is life-threatening, and its cardinal signs are changes in behaviour and difficulty walking in a straight line.

Acclimatisation Is the Protection

Acclimatisation means giving the body scheduled time at a given height before going higher. On Kilimanjaro it is built into the itinerary as a climb-high-sleep-low pattern, and it is the reason a longer route has a better summit record than a short one.

• Choose a route with enough days to gain height gradually.
• On rest days, walk to a higher point and return to sleep lower.
• Keep the daily gain in sleeping altitude modest, especially above 4,000 m.
• Build spare days into the plan so a slow day does not become a failure.

Prevention

1. Climb slowly, and let the itinerary be led by the slowest member of the group.
2. Drink enough to stay hydrated - typically three to four litres a day.
3. Eat well. Altitude kills appetite, and under-fuelling compounds the problem.
4. Avoid alcohol and sleeping pills above 3,000 m.
5. Sleep at a lower camp after the highest point of the day.
6. Take any prescribed acetazolamide exactly as directed, in advance.

What to Do If Symptoms Appear

The sequence below is what our guides are trained to do, and it is worth knowing before you are at 4,500 m with a headache.

1. Stop ascending. Do not go higher today, whatever the schedule says.
2. Rest and reassess through the day with fluids, food and warmth.
3. Do not leave alone. A person with altitude illness must never descend or walk out by themselves.
4. Descent is the cure. If symptoms do not improve, or worsen, lose height as soon as possible.
5. Summit is refused if the guide judges the group or an individual is not fit to continue.

Medical Conditions and Medication

Next Steps

Altitude is the main health risk on the mountain. The wider safety picture - crew, weather, and evacuation - is covered next.

Good to know

Frequently asked questions

Can you summit Kilimanjaro with altitude sickness?

TODO: answer clearly - no, and explain what happens instead.

Do antibiotics prevent altitude sickness?

TODO: clear up the common misconception and explain acetazolamide instead.

How fast should we climb to avoid altitude sickness?

TODO: give a concrete sleeping-altitude rule of thumb above 3,000 m.

Does drinking extra water prevent it?

TODO: be precise - hydration helps, it does not prevent AMS.

Is Kilimanjaro safe for people with asthma or heart conditions?

TODO: advise medical clearance and describe the on-mountain response plan.