How to Avoid Altitude Sickness on ABC Trek (12 Effective Tips)

You can lower your risk of altitude sickness on the Annapurna Base Camp (ABC) trek by climbing slowly, adding rest days, drinking enough water, eating regularly, avoiding alcohol and descending if symptoms get worse. Base camp sits at about 4,130 metres, high enough for Acute Mountain Sickness (AMS) to affect anyone, whether they are fit or not.

The good news is that most AMS is mild and avoidable with a sensible plan. This guide explains the symptoms, shows where on the trail they usually appear, and gives 12 practical tips you can use. It is written for first-time trekkers, including Indian trekkers heading to Nepal, and it is general information, not medical advice. Talk to a doctor or travel clinic before you go, especially if you have a heart, lung or other medical condition.

Quick summary

AMS usually happens when you gain height faster than your body can adjust. The most effective protection is a slow, well-paced itinerary. Everything else on this list, such as water, food, sleep and listening to your body, supports that one idea.

Key takeaways

• ABC is about 4,130 m. AMS can affect anyone, regardless of age or fitness.
• Slow ascent is the best prevention. Above 3,000 m, health guidelines advise not raising your sleeping altitude by more than about 500 m per day, with a rest day every 3 to 4 days.
• Drink enough fluids, eat carbohydrate-rich meals and avoid alcohol.
• Never ignore a headache that gets worse. Rest, do not go higher, and tell your guide or group.
• Descending is the main treatment if symptoms worsen. Going down about 300 to 1,000 m usually helps.
• Confusion, loss of balance, breathlessness at rest or a wet cough are emergencies. Descend and get medical help.

What is altitude sickness?

Altitude sickness, also called Acute Mountain Sickness, happens when your body has trouble adjusting to lower oxygen levels at height. The air pressure drops as you climb, so each breath carries less oxygen. Your body adapts, but it needs time. If you climb too fast, symptoms can appear.

The NHS notes that altitude sickness mainly happens above about 2,500 m, and symptoms often begin 6 to 10 hours after arriving at a new height. MedlinePlus gives a similar threshold of around 2,400 m and says faster ascent raises the risk. ABC is lower than the Everest Base Camp trek, which reaches about 5,364 m, but it is still above the level where AMS is common.

Common symptoms of AMS

Mild symptoms usually ease with rest at the same altitude. Serious symptoms may signal fluid on the lungs (HAPE) or swelling of the brain (HACE). These can become life-threatening, and the answer is to descend and get medical help right away.

Where on the ABC trail does AMS usually show up?

Most people start to notice the altitude above roughly 2,500 m. The steeper stretch from Sinuwa up through Deurali to base camp is where trekkers tend to feel it most. Elevations vary slightly between sources, so treat these as approximate.

Being a little short of breath above 3,000 m is normal. A severe headache, repeated vomiting or confusion is not, and should never be pushed through.

1. Walk slowly from day one

The early part of the trail feels easy, so many beginners walk fast. That is a mistake. A fast pace raises your breathing rate and tires you out, which makes it harder to acclimatise. A simple rule used by many guides is to walk slowly enough that you can still hold a conversation.

Even very fit trekkers can get AMS if they climb too quickly. Fitness helps with the walking, not with the altitude.

2. Build rest days and a gentle ascent rate into the plan

This is the most important tip. Health guidance, including the Wilderness Medical Society guidelines and the NHS, suggests that once you are above about 3,000 m you should not raise your sleeping altitude by more than about 500 m per day, and should take a rest day (no gain in sleeping height) every 3 to 4 days.

Compare that with the trail. From Deurali (about 3,230 m) to ABC (about 4,130 m) is roughly 900 m. Spreading that over two nights, with a stop at Machapuchare Base Camp (about 3,700 m), keeps each step within the guidance. Some fast itineraries skip that stop, which raises the risk.

An example of a more gradual ABC plan

This is an illustration of pacing, not a fixed route. Real itineraries vary with weather, trail conditions and your guide’s advice.

If you feel unwell on any day, add a rest day before going higher. An extra day costs very little compared with the cost of a ruined trek.

3. Drink enough fluids

Dehydration makes AMS feel worse, and cold weather can hide thirst. The NHS and MedlinePlus both recommend drinking enough fluids and avoiding dehydration at altitude. There is no single number that suits everyone. A practical approach is to sip water regularly through the day and check that your urine stays pale.

• Carry a reusable bottle.
• Do not wait until you feel thirsty.
• Use water that is boiled or treated. Many teahouses sell boiled or filtered water, and you can also carry purification tablets.
• Warm drinks such as ginger tea or soup count towards fluids.

4. Do not ignore mild symptoms

A mild headache after reaching a new village can get worse overnight. If you feel unwell:

• Stop climbing and rest at the same altitude.
• Drink and eat something light.
• Tell your guide or trekking partner right away.
• Do not go higher until the symptoms have gone.

The NHS says symptoms usually improve within one to three days, and advises descending around 300 to 1,000 m if they worsen or do not improve after a day. Listening to your body matters more than sticking to the schedule.

5. Eat even when you are not hungry

Altitude often reduces appetite, but your body needs energy to trek and to adapt. MedlinePlus recommends carbohydrate-rich meals at altitude. Dal bhat (rice, lentils, vegetables) is a popular choice on the trail because it is filling and easy to find. Other good options are soup, potatoes, oatmeal, noodles and plain rice. Heavy, oily food can sit badly at height, so keep meals simple.

Indian vegetarian trekkers usually find enough choices on teahouse menus along this route, but it is worth telling your guide about dietary needs in advance.

6. Avoid alcohol and smoking

Both the NHS and MedlinePlus advise avoiding alcohol at altitude. Alcohol can dehydrate you and can make sleep and breathing worse. Smoking also reduces how well your body uses oxygen. Save the celebration for after you are back at lower altitude.

7. Sleep and rest properly

Many trekkers arrive in Nepal tired from travel. Give yourself a day or two in Pokhara or Kathmandu before starting the trek. On the trail, pack a warm sleeping layer, keep your clothes dry and avoid caffeine late in the day. Sleep is often broken at height, and that is common. Rest still helps.

8. Ask a doctor about preventive medicine

Some trekkers use a prescription medicine called acetazolamide (often sold as Diamox) to help reduce the risk of AMS. MedlinePlus says it helps symptoms, especially when started before the ascent, and the Wilderness Medical Society guidelines list it as a preventive option. The NHS advises seeing a doctor or travel clinic before climbing if you have had altitude sickness before or plan to ascend quickly.

It is not a substitute for a slow ascent, it has side effects, and it is not suitable for everyone (for example, people with certain allergies). Do not take it on a friend’s advice. Get a prescription and dosing instructions from a doctor who knows your medical history.

9. Prepare your body before the trek

You do not need to be an athlete, but a few weeks of regular walking, stair climbing and uphill practice with a light backpack can make the trek less tiring. The less tired you are, the easier it is to keep a steady pace. If you live in a city, climbing stairs and doing longer weekend walks is a simple start.

10. Trek with an experienced guide

A good local guide can spot early signs of AMS, adjust the pace and make the call to rest or descend. This is especially helpful for first-time trekkers. Read why in our article on trekking with a local trekking company in Nepal. Whichever company you choose, check recent reviews, ask how they handle altitude problems and confirm that your guide knows the emergency plan. One option that publishes ABC itineraries is Nepal Hiking Team, but compare several operators before booking.

11. Descend if symptoms get worse

Descent is the main treatment for AMS. The Wilderness Medical Society guidelines call it the single best treatment for AMS and HACE, and say symptoms usually improve after going down about 300 to 1,000 m. Do not wait until morning if the signs are serious.

Get help and descend straight away if you or a companion has:

• Confusion or strange behaviour
• Trouble with balance or walking in a straight line
• Breathlessness at rest
• A cough with frothy or bloody spit
• Blue or grey lips or skin
• Extreme sleepiness or difficulty waking

A person with suspected HACE should not descend alone.

12. Choose the season carefully

Spring (March to May) and autumn (September to November) are the usual trekking seasons in Nepal, with more stable weather and good mountain views. Winter is colder, and monsoon brings slippery trails and poor visibility. Cold and wet conditions do not cause AMS, but they make the trek more tiring and uncomfortable.

Planning for Indian trekkers

• Documents. According to Buddha Air’s India to Nepal travel page, Indian citizens flying to Nepal need a valid passport or a voter ID, and an Aadhaar card is not accepted as a travel document. Carrying your passport is the safest choice. Check the latest rules with your airline before travelling.
• Permits. Trekking in the Annapurna region normally needs permits arranged through registered channels. Fees and requirements change, so ask your trekking company or check the official Nepal tourism sources rather than relying on an old blog post.
• Insurance. Look for travel insurance that covers trekking at your maximum altitude and emergency evacuation. Many standard policies exclude high-altitude trekking.
• Medical checks. Visit a doctor before you go, especially if you have a heart, lung or blood-pressure condition.

For general trip planning, read our first-time international travel tips and our list of the best trekking destinations in the world. If you prefer to stay in India, see our guide to hidden hill destinations in India.

Common mistakes that raise your risk

• Climbing too fast because the lower trail feels easy.
• Skipping the stop at Machapuchare Base Camp to save a day.
• Drinking too little water.
• Ignoring a headache and hoping it goes away overnight.
• Drinking alcohol to celebrate before the summit day.
• Starting the trek already exhausted from travel.
• Continuing upward after a guide has advised rest or descent.

Frequently asked questions

Can beginners get altitude sickness on the ABC trek?

Yes. The route reaches about 4,130 m, high enough for AMS. Fitness does not protect you from it. Pacing, rest days, hydration and early action on symptoms matter more.

Is ABC easier than Everest Base Camp for altitude sickness?

It is lower, so the risk is generally lower, but AMS can still affect anyone who climbs too quickly. Everest Base Camp reaches about 5,364 m.

Does garlic soup prevent altitude sickness?

Garlic soup is a popular warm dish on Himalayan trails, but we did not find reliable evidence that it prevents AMS. Enjoy it for warmth and fluids, and do not use it in place of a slow ascent.

Should I take Diamox for the ABC trek?

It is a prescription medicine that some trekkers use to help reduce the risk. Whether it is right for you depends on your health and itinerary, so ask a doctor or travel clinic well before your trip.

What should I do if my headache gets worse at night?

Stay where you are, do not go higher, drink water and tell your guide or companion. If it gets worse or you notice confusion, vomiting or breathlessness at rest, descend and get medical help.

How we checked this guide

Medical and ascent-rate advice was checked against the NHS, MedlinePlus and a summary of the Wilderness Medical Society guidelines in October 2026. Trail elevations were cross-checked against a trekking operator’s elevation page and vary slightly between sources. Permit fees were not quoted because they change, so confirm them with official Nepal sources or a registered trekking company. This article is general information, not medical advice.

Sources

• NHS: Altitude sickness
• MedlinePlus: Altitude sickness
• Outdoor Ed: Summary of Wilderness Medical Society guidelines for acute altitude illness
• Ace the Himalaya: Annapurna Base Camp trek elevation
• Buddha Air: India to Nepal travel

Trekking in Nepal? Nepal runs 15 minutes ahead of India. Our Nepal time to India time guide explains the gap and what it means for buses, flights and calls home.

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Varinder Kaur

Varinder Kaur is from Amritsar, India. She has traveled to well-known places across India, including Darjeeling, and to a few countries abroad, and shares travel experiences and practical tips for travelers through OpinionHook.