Destinations above 2500 metres may expose the traveler to possible altitude sickness by reducing the amount of inspired oxygen. Presenting symptoms may include headache, faintness or giddiness, breathlessness, nausea, vomiting or reduced exercise tolerance. Symptoms often present within 36 hours but may appear at a few days.
Previous altitude sickness increase the risk of recurrence.
Ascents greater than 500 metres / day above 3000 metres increase the likelihood of altitude sickness. A rest day every 3-4 days is recommended to assist acclimatization. Spending 2 nights at high altitudes in the 30 days preceding, before ascending further is beneficial.
Ibuprofen, Diamox and Dexamethasone have been found to be useful in treating altitude sickness. Nifedipine may also be useful
Contraindications to high altitude travel are severe COAD, severe or unstable ischaemic heart disease, heart failure, pulmonary hypertension, pregnancy, cerebrovascular disease or DVT.