Altitude Sickness: How to Prevent and Manage It When Travelling

If you’re planning a trip to a mountainous region or high-altitude destination — like Peru, Nepal, or even cities such as La Paz or Cusco — it’s important to be aware of altitude sickness, also known as acute mountain sickness (AMS).

In this guide, we’ll explain what altitude sickness is, how to spot the symptoms, and the best ways to prevent and treat it safely while travelling.

🏔️ What Is Altitude Sickness?

Altitude sickness happens when you ascend to altitudes over 2,500 metres too quickly, before your body has had time to adjust (a process called acclimatisation). At higher altitudes, the air is thinner, and there’s less oxygen available. This can cause symptoms ranging from mild headaches to life-threatening complications if not addressed early.

✅ Important note: Your age, fitness level or previous travel history doesn’t predict whether or not you’ll get altitude sickness.

⏰ When Do Symptoms Start?

Symptoms typically start within 6 to 24 hours of arrival at high altitude and include:

• Headache

• Nausea or vomiting

• Dizziness or lightheadedness

• Tiredness or fatigue

• Loss of appetite

• Breathlessness on exertion

🚨 Severe Complications to Watch For

Ignoring symptoms can lead to two dangerous conditions:

1. High Altitude Cerebral Oedema (HACE)

A swelling of the brain due to low oxygen.
Symptoms: Confusion, poor coordination, hallucinations, headache, nausea.

2. High Altitude Pulmonary Oedema (HAPE)

A build-up of fluid in the lungs.
Symptoms: Breathlessness (even at rest), blue lips or skin, chest tightness, frothy cough, extreme fatigue.

🆘 Both HACE and HAPE can be life-threatening and require urgent descent and medical attention.

✅ How to Prevent Altitude Sickness

The best prevention is slow, gradual ascent. Here's what to do:

• Don’t fly directly to high-altitude locations, if avoidable

• Take 2–3 days to adjust before trekking above 2,500m

• Climb no more than 300–500m per day

• Rest every 600–900m gain, or every 3–4 days

• Never sleep higher if you feel unwell

• Drink plenty of water and avoid alcohol

• Eat high-calorie, light meals

• Avoid overexertion for the first 24 hours

• Always trek with an experienced guide

• Make sure your travel insurance covers altitude-related emergencies and helicopter evacuation

💊 Medication Options

Acetazolamide (Diamox®) – for prevention or treatment

• Dose: 125mg twice a day

• Start: 1 day before ascent

• Continue: For at least 2 days after reaching the highest altitude

• Note: This is an off-label use — speak to a GP before travel

👉 Read the full SPC for Diamox® (Acetazolamide)

Dexamethasone – for HACE (brain swelling)

A steroid used to reduce cerebral oedema while descending.

Nifedipine – for HAPE (fluid in the lungs)

Relieves pressure in the lungs, making breathing easier during descent.

👨‍⚕️ When to Get Medical Advice

If you're travelling to high-altitude destinations or trekking above 2,500m, it's a good idea to book a pre-travel consultation.

At Ready Health Clinic in Standish, we provide:

• Individualised travel advice

• Prescriptions for altitude sickness prevention

• Support for safe travel and emergency planning

📍 Serving Wigan, Chorley, Bolton, Horwich and surrounding areas
📅 Book online or call us on 01257 676001

📌 Summary

Altitude sickness is a real risk for travellers going above 2,500 metres — but with the right knowledge, a slow ascent, and access to preventive medication like Diamox, you can stay safe and enjoy your adventure.

If you're unsure whether altitude medication is right for you, speak to our clinical team before your trip. Safe travels start with good preparation.