This article was first published in 2013. Travel health advice, vaccine recommendations and entry requirements change over time, so check our latest guides below or speak with a TMA travel doctor before you travel.
Key points
- Altitude sickness can occur above about 2,500 metres, including on arrival in high-altitude cities such as Cusco.
- Symptoms include headache, nausea, dizziness and weakness, and can be worse at night.
- Above 3,000 metres, avoid climbing more than 500 metres a day, and do not go higher if you have symptoms.
- A doctor can prescribe medicine to help you acclimatise. Talk to a travel doctor before your trip.
Reviewed and updated November 2026.
Update: Medicine choices and doses for preventing altitude sickness should be individual. Speak with a travel doctor before you travel rather than relying on the doses in this article.
| ... Prepared by TMA Member Maitland: Dr Puru Sagar Chromis
A survey among travelers departing from Cuzco International airport in Peru showed that almost half of all travelers (48.5%) interviewed reported symptoms of altitude sickness, and 17% had severe AMS. One in five travelers with AMS was forced to alter their travel plans. Three people were admitted to hospital and one was urgently evacuated. Only one-sixth (16.6%) of the group used Acetazolamide (Diamox) for prevention of AMS, but more than 60% used coca leaf products. Unfortunately, the use of coca-leaf products (usually tea) was found to be associated with a greater risk of developing AMS in this study. Use of coca-leaf can have other negative side-effects (changes in circulation and cardiac arrhythmias) as well as a positive urine drug screen to cocaine. Other recent reviews have found that Diamox 250 mg half tab twice daily reduced the risk of developing AMS by about 48%. There was no benefit in taking higher doses. Diamox is strongly recommended for travelers flying into Cuzco (elevation 3,225 m) and is often required at lower altitudes (around 2,000 m). These scientific studies underline the need to obtain accurate and up-to-date advice from an experienced travel medicine practitioner before undertaking trips to altitude. Prevention is really worthwhile. The Travelling Well iPad app or iBook from Dr Deb the Travel Doctor has very useful information on preventing and recognizing altitude illness.
|
|||
Frequently asked questions
At what altitude does altitude sickness start?
Healthdirect notes it happens at altitudes above about 2,500 metres.
What should I do if I get altitude sickness?
Do not climb higher. Rest, and descend if symptoms worsen. Confusion, unusual behaviour or severe breathlessness are emergencies that need help to descend straight away.
Sources
Related travel health guides
Planning a trip? A TMA travel doctor can tailor your vaccines and travel health advice to your itinerary.