Altitude Sickness in Nepal: How to Recognise it, Prevent it, and Stay Safe

Studies in Nepal’s high mountain regions show that between 30% and 50% of trekkers experience symptoms of altitude sickness. On the Annapurna Circuit, a recent study found an incidence of 45%. In the Everest region, the figure sits around 30%. So if you are heading above 2,500 metres, the chances are real.

What is altitude sickness?

Altitude sickness happens when your body does not get enough oxygen at high altitude. The air contains the same percentage of oxygen as at sea level, but the air pressure is lower. Your lungs take in less oxygen with each breath. Your body needs time to adjust, and that process is called acclimatisation.

Altitude sickness comes in three forms:

1. Acute Mountain Sickness (AMS) The mild form. The symptoms feel a lot like a hangover: headache, nausea, fatigue, loss of appetite, trouble sleeping. Some people barely notice it. Others feel awful. Either way, AMS is a warning sign. Your body is telling you it needs more time.
2. High Altitude Pulmonary Edema (HAPE) A life-threatening condition. Fluid builds up in the lungs. The symptoms are a cough (wet or dry), shortness of breath even at rest, and all the symptoms of AMS. Descend immediately and seek medical help.
3. High Altitude Cerebral Edema (HACE) Also life-threatening. The brain swells. The symptoms are stumbling or losing balance (ataxia), confusion, drowsiness or strange behaviour. Descend immediately and seek medical help.

For all three, the same rule applies: descent is the best medicine.

How we approach altitude on our treks

Every trek we design above 2,500 metres is built around one principle: give your body time. That is not just our preference, that is what the research shows. A recent study at the Himalayan Rescue Association aid post in Manang found that almost a third of altitude sickness patients had ascended too quickly, more than 500 metres per day above 2,500 metres.

So this is what we do:

• Acclimatisation days are built into the itinerary. On our higher-altitude treks, you will have rest days at strategic points. These are not lazy days. They are part of your body’s training. You stay at altitude, walk a little higher during the day, and sleep lower. That is how your body adapts.
• Maximum 500 metres ascent per sleeping altitude per day above 2,500 metres. This is the international guideline, and we stick to it. Some routes ask for creativity to make this work, and that is exactly what your guide does.
• Daily check-ins between you and your guide. Your guide is experienced and watches closely, but your guide cannot feel what you feel. Honest, daily communication between you and your guide is one of the most important safety tools we have. How is your headache today? How did you sleep? How is your appetite? These are not small talk questions. They are the moments where we catch something early.
• A team that knows what to do. Our guides are trained to recognise the signs of AMS, HAPE and HACE. They carry first aid supplies. They know which guesthouses to head to, which routes to descend, and when to call for evacuation. Govinda has guided on these routes for over a decade. He has seen it all, and he has trained the team accordingly.

A small story from Valerie

On my first trek in Nepal, I lost my appetite as we gained altitude. I knew about staying hydrated, but no one had told me about eating. I started sharing meals with my best friend, and I thought I was just not very hungry.

Later I learned that loss of appetite is one of the early signs of altitude sickness. I was lucky. Nothing serious happened. But ever since, I make myself eat full portions, even when I do not feel like it. My body is working hard up there, walking long days, staying warm, processing the altitude. It needs fuel.

That is why we tell every traveller the same thing: do not skip meals. If the portions feel too big, eat soup and small snacks in between. But keep eating.

What you can do yourself

Your guide and your team take care of a lot. But your body is yours, and there are things only you can do.

• Drink plenty of water. Aim for three to four litres per day at altitude. Your body loses more water through breathing in the dry mountain air than you might think.
• Avoid alcohol and limit coffee. Both are diuretic, which means they make you urinate more and dehydrate faster. Alcohol also masks the symptoms of altitude sickness, which is dangerous when you need to read your body clearly.
• Eat three meals a day, plus snacks. As Valerie’s story shows, your appetite may drop. Eat anyway.
• Tell your guide how you feel. Honestly. This is the single most important thing. Some travellers downplay symptoms because they want to keep going. Please do not. Your guide cannot help you if you do not tell them what is going on.
• Sleep low, climb high. On acclimatisation days, walk to a higher point during the day, then return to sleep at a lower altitude. Your body adapts faster this way.

What about Diamox?

Diamox (acetazolamide) is a medication that helps your body acclimatise faster. It is widely used and well researched.

We do not advise taking Diamox preventively. We believe it is important to feel how your body responds to altitude, rather than masking the early signs. If you suppress symptoms preventively, you may miss a warning that something is wrong.

That said, we do recommend bringing Diamox with you on higher-altitude treks. It can be useful to have on hand if descending immediately is not possible, or if symptoms develop and your doctor or guide advises you to take it. Talk to your GP or travel doctor before your trip about what to bring and when to use it.

Walk safely, return safely

Altitude is part of what makes Nepal so extraordinary. The Himalayas are not gentle, but they are honest. They reward travellers who pay attention, who listen to their bodies, and who walk with people who know the way.

We have built our treks around exactly that. Acclimatisation days that are not negotiable. Daily distances that fit what your body can handle. Guides who notice things before you do. And a team that has been doing this for over a decade.

If you want to know more about altitude or about a specific trek, just ask. You can reach us by email, meet us at a travel fair, or get in touch through our [contact page]. We are happy to talk it through.

Reliable sources for more information

• Himalayan Rescue Association — non-profit operating high-altitude aid posts in Pheriche and Manang, with decades of experience in altitude illness.
• UIAA Medical Commission — international mountaineering federation with detailed medical advice.
• Wilderness Medical Society Practice Guidelines — evidence-based clinical guidelines on the prevention and treatment of altitude illness.

Disclaimer: This blog provides general information and is based on our experience and on the sources listed above. It is not a substitute for medical advice. If you have questions or concerns about altitude sickness, please contact your GP or a travel doctor before your trip.