How should I prepare for a trip to high altitude?

Updated

Start by treating altitude as a planning variable, not a risk you deal with once you arrive. The core preparation is: get individual medical advice before you go, plan a gradual ascent with rest days, carry the right medication and equipment, and know the warning signs that mean descend rather than push on. Medex (medex.org.uk) is a UK-based medical expedition charity that publishes a free booklet on travelling at high altitude, which is a reasonable starting point for general background before you speak to a clinician.

Get health advice before you book

Altitude illness is not predictable from fitness alone. Fit people get it; unfit people sometimes don't. That is why the first step is a conversation with a travel medicine clinic or a doctor experienced in high-altitude medicine, ideally several weeks before departure.

Bring these to that appointment:

  • Your exact itinerary, including maximum sleeping altitude and how fast you get there
  • Any heart, lung, or neurological conditions, and current medications
  • Pregnancy status, if relevant
  • Previous altitude illness — this is one of the strongest predictors of getting it again

The clinician decides whether you need preventive medication such as acetazolamide, and whether you should travel at all. This article cannot make that call for you; it only tells you what to prepare.

Plan an ascent rate you can actually keep

The single most effective prevention is slow ascent. A widely used rule of thumb above 3,000 m is to increase your sleeping altitude by no more than about 300–500 m per day, with a rest day every 1,000 m or so. Above roughly 3,000 m, spend a second night at the same altitude before going higher.

Practical ways to build this into a trip:

  • Add a buffer day at a mid-altitude town before the final push
  • Sleep lower than your highest point of the day where the terrain allows
  • Avoid flying or driving directly to very high sleeping altitudes if you have a choice
  • Treat the schedule as adjustable — bad weather and illness are normal, and a fixed summit date is how people get into trouble

Pack for the altitude, not just the destination

Category What to carry Why
Medication Personal prescription medicines, plus what your clinician recommends for altitude illness Availability is limited above the tree line
Monitoring Pulse oximeter if your clinician suggests one Gives an objective reading alongside how you feel
Warmth Layered insulation, windproof shell, hat, gloves Cold and altitude compound each other
Hydration and food Water treatment, high-calorie snacks Appetite and thirst cues are unreliable at altitude
Descent options Cash, permits, or a plan for getting down fast The main treatment for severe altitude illness is descent

Do not rely on buying altitude medication at your destination. Carry what you need, in original packaging, with a copy of your prescription.

Know the signals that mean stop

Learn to separate normal altitude adjustment from illness.

Expected at altitude: mild breathlessness on exertion, waking at night, needing to urinate more, mild headache in the first day or two.

Warning signs:

  • Headache that does not respond to painkillers and rest
  • Nausea or vomiting, especially with headache
  • Dizziness, unsteadiness, or confusion
  • Breathlessness at rest
  • Cough, or fluid sounds in the chest
  • Swelling of the face, hands, or ankles

Confusion, breathlessness at rest, and a wet cough are emergencies. The response is to descend and get medical help, not to wait until morning.

Use Medex as background, not as a diagnosis

Medex publishes a free booklet on travelling at high altitude, aimed at travellers and expedition members. Read it to understand the general mechanisms and to prepare better questions for your clinician. It does not replace individual medical assessment, and it cannot tell you whether a specific itinerary is safe for you.

A sensible sequence: read the general material, write down your itinerary and health history, then take both to a travel medicine appointment.