Altitude sickness happens when you travel to high altitude — usually above about 2,500 metres — faster than your body can adjust to the thinner air. It typically causes headache, feeling sick, dizziness, tiredness and poor sleep, starting within the first day or two at height. It can affect anyone: being fit and healthy doesn't stop you getting it.
Treatments & products
Altitude Sickness — your questions, answered
Can I prevent altitude sickness?
The best prevention is ascending slowly — building in rest days and, where you can, sleeping at a lower altitude than the highest point you reached that day. Avoid alcohol and keep well hydrated. If a rapid ascent is unavoidable, acetazolamide is a prescription option our pharmacist can discuss and supply after an online travel-health consultation.
What should I do if I get symptoms?
Stop going any higher and rest where you are — symptoms usually settle within a day or two once you stop ascending. Simple painkillers can ease the headache, and it's important to keep drinking fluids. Only carry on climbing once you feel completely better. If symptoms don't improve, or get worse, go down to a lower altitude.
When is altitude sickness an emergency?
Get urgent medical help if you or a companion become breathless at rest, develop a persistent cough, or become confused, clumsy or unsteady on your feet — these can be signs of fluid on the lungs or brain, which is life-threatening. Descend to a lower altitude straight away, and never leave someone with these symptoms on their own.
Information only — always read the patient leaflet and ask our pharmacist if you're unsure. Prescription treatments are supplied only after a consultation and our pharmacist's approval.