Altitude Sickness

When to book an altitude sickness consultation

Book a travel health consultation before any trip taking you above 2,500 metres. Symptoms usually appear 6 to 10 hours after reaching altitude:

• Headache
• Nausea or vomiting
• Dizziness or light-headedness
• Loss of appetite
• Fatigue and exhaustion
• Difficulty sleeping
• Shortness of breath during activity

Mild symptoms usually improve within 1 to 3 days if you stop ascending. Descend immediately and get emergency help for severe breathlessness at rest, a persistent cough with frothy or blood-tinged sputum, confusion, disorientation or hallucinations, loss of balance or coordination, extreme drowsiness, or a blue or grey tinge to the lips or fingertips.

What is altitude sickness?

Altitude sickness happens when your body cannot get enough oxygen from thinner air at height, typically above 2,500 metres when you ascend too quickly. It can affect anyone, regardless of age or fitness. There are three forms:

• Acute Mountain Sickness (AMS) - the most common and mildest, causing headache, nausea and fatigue
• High Altitude Pulmonary Oedema (HAPE) - a dangerous build-up of fluid in the lungs causing severe breathlessness
• High Altitude Cerebral Oedema (HACE) - life-threatening swelling of the brain causing confusion and loss of coordination

Altitude sickness cannot occur in the UK. It affects travellers to destinations such as the Himalayas and Everest Base Camp, Kilimanjaro, the Andes, Machu Picchu and Cusco, La Paz, the Alps, the Atlas Mountains and Lhasa.

How to prevent altitude sickness

• Avoid travelling from low altitude to above 3,500 metres in a single day
• Spend a few days acclimatising below 2,500 metres before going higher
• Above 3,000 metres, increase your sleeping altitude by no more than 300 to 500 metres per day
• Plan rest days every 3 to 4 days above 3,000 metres
• Stay well hydrated and avoid alcohol in the first few days
• Avoid strenuous activity on your first day at a new altitude
• Eat a light, high-carbohydrate diet

Acetazolamide (Diamox)

For higher-risk travellers or very high destinations, acetazolamide can help your body adjust faster by increasing your breathing rate and oxygen intake. It is prescription-only, usually started 1 to 2 days before ascending and continued during the ascent. Common side effects include tingling in the fingers and toes, increased urination and a change in the taste of fizzy drinks. It is not suitable for everyone, and our independent prescribing pharmacists can assess you and issue a prescription during your consultation, saving a separate GP appointment.

Find altitude sickness advice near you

No GP referral required. Independent prescribing pharmacists, fast appointments often available within days, and full travel health consultations covering altitude, vaccinations and antimalarials. Use the postcode search above to find your nearest Allied Pharmacy.