How Do I Prevent Altitude Sickness on a Base Camp Trek?

Trekking to high altitudes in Nepal — whether it’s Everest Base Camp (5,364m), Annapurna Base Camp (4,130m), or Manaslu Circuit — is a physical and mental challenge. But one of the biggest risks at these elevations isn’t the hiking itself.

It’s altitude sickness.

Also known as Acute Mountain Sickness (AMS), this condition affects trekkers who ascend too quickly without giving their bodies enough time to adapt to thinner air.

The good news? It’s largely preventable.

Here’s how to avoid altitude sickness and stay safe while trekking through the breathtaking Himalayas.

As you ascend above 2,500 metres, the oxygen level in the air drops, putting extra stress on your body. Your lungs and brain work harder to get the oxygen they need, which can lead to symptoms if you don’t acclimatise properly.

Common Symptoms of AMS:

• Headache
• Dizziness
• Nausea or vomiting
• Fatigue
• Loss of appetite
• Difficulty sleeping

If left unmanaged, AMS can develop into serious conditions like:

• High Altitude Pulmonary Edema (HAPE) — fluid in the lungs
• High Altitude Cerebral Edema (HACE) — swelling in the brain

These are medical emergencies that require immediate descent.

This is the most important rule.

• Don’t gain more than 300–500m of sleeping elevation per day once above 3,000m
• Include acclimatisation days every 2–3 days (especially at Namche Bazaar and Dingboche on the Everest route)

See our Everest Base Camp Trek Itinerary designed with acclimatisation built in.

Drink at least 3–4 litres of water per day.
High altitude increases your breathing rate and causes fluid loss. Dehydration worsens AMS symptoms.

Avoid:

• Alcohol (it dehydrates and affects breathing)
• Excess caffeine (increases urination and fluid loss)

Your body uses more energy at altitude. Eat regular meals and include carbohydrates to fuel your efforts. Even if you lose appetite (common at altitude), try to keep eating small portions throughout the day.

Climb high, sleep low” is a golden rule.
On rest days, take short hikes to higher elevations, then return to your teahouse to sleep lower. This trains your body to adapt without pushing too hard.

Examples:

• Hike to Everest View Hotel from Namche
• Hike to Nagarjun Hill from Dingboche

Some trekkers take acetazolamide (Diamox) before and during high altitude travel.

It helps your body adjust by speeding up breathing rate.

Speak with your doctor before taking any medication and understand potential side effects.

Dosage typically starts at 125–250mg twice a day from around 3,000m.

If you develop symptoms of AMS:

• Stop ascending immediately
• Rest and monitor your condition
• If symptoms worsen, descend at least 500 metres

Never “push through” altitude sickness. It can be deadly.

At Base Camp Himalayas, our guides are trained to monitor symptoms daily, assess severity, and adjust the route as needed.

• Sleep at lower elevations when possible
• Don’t rush the trek to “tick it off” — it’s not a race
• Follow your guide’s advice on pacing and rest days

While fitness won’t prevent altitude sickness directly, it helps you:

• Handle physical strain better
• Focus on breathing and recovery
• Avoid exhaustion, which weakens your body’s response to altitude

Training recommendations:

• Hike with a pack 2–3 times per week
• Include cardio: cycling, swimming, stairs
• Practice walking on varied terrain

When you travel with Base Camp Himalayas, we provide:

• Experienced local guides trained in altitude response
• Built-in rest days in all high-altitude treks
• Oximeter checks to monitor blood oxygen
• Emergency backup plans including evacuation support

We believe high-altitude trekking should be safe, not scary.

Warm layers, moisture-wicking clothing, and weatherproof jackets help your body stay stable in cold, thin air.

Cold stress can compound the effects of altitude, so staying dry and warm supports your overall health during the trek.

Altitude sickness is avoidable — if you respect the mountain and prepare properly.

At Base Camp Himalayas, every itinerary is crafted with altitude safety at its core. We take no risks with your health or your experience.

Ready to trek with confidence?

Contact us today to start planning your high-altitude adventure, safely and professionally.