How is altitude sickness different in travellers?

A person who normally lives near sea level may notice headache, dizziness, unusual tiredness, nausea, reduced appetite or poor sleep after going higher. The symptoms may resemble dehydration, jet lag, infection or alcohol effects, but the timing after ascent is a useful clue. Fitness does not remove the risk, and a previous comfortable trip does not guarantee the next ascent will feel the same. Children and adults can both be affected.

Pause the ascent when symptoms begin and rest at the same altitude. Drink normally, avoid alcohol and sedating medicines unless a clinician has advised them, and tell a travel companion how you feel. Do not continue climbing while symptoms are present. A travel clinician can discuss gradual ascent, acclimatisation and whether preventive medicine is appropriate for your route and health history.

Get urgent medical help for confusion, difficulty walking, fainting, severe breathlessness at rest, blue or grey lips, chest tightness, or a worsening headache with vomiting. These may indicate a serious altitude-related illness. Move to a lower altitude promptly when it is safe, with assistance, and do not leave a severely unwell traveller alone.

Ask how quickly you can ascend safely, which symptoms mean you must stop, whether your medicines or heart and lung history change the plan, and what emergency oxygen or evacuation arrangements are available. Discuss the route, sleeping altitude and access to medical care before departure.