how to prevent altitude sickness
Altitude sickness is best prevented by going up slowly, letting your body acclimatize, staying hydrated, and using medication like acetazolamide in higher‑risk situations after talking with a doctor.
Quick Scoop
What altitude sickness is
Altitude sickness (often called acute mountain sickness, AMS) happens when you go to high elevations too quickly and your body doesn’t get enough time to adjust to thinner air.
Typical early symptoms include headache, nausea, fatigue, dizziness, and poor sleep, and they can progress to dangerous brain or lung swelling (HACE, HAPE) if ignored.
Core prevention rules
- Ascend slowly
- Once above roughly 2,400–2,500 m (about 8,000 ft), increase your sleeping altitude by no more than about 300–500 m (1,000–1,600 ft) per night.
- For every 900–1,000 m (3,000 ft) you gain, schedule an extra rest day at the same altitude before going higher.
- If you fly directly into a high city (for example, a ski town or trekking base above 2,500 m), build in an easy “acclimatization day” before doing anything strenuous.
- Use “climb high, sleep low”
- Hike or ski higher during the day, then drop back down to sleep lower if you can; this helps your body adapt without over‑stressing it.
- Many guided treks plan short acclimatization hikes from camp in the afternoon, then return to the same camp for the night.
- Hydrate and eat smart
- Drink water regularly; the air is dry at altitude and you lose more fluid through breathing.
- Avoid getting dehydrated, but don’t force huge amounts of water beyond thirst; over‑hydration can also cause problems.
- Favor light, carbohydrate ‑rich meals (grains, pasta, bread, fruits) for easier energy and digestion.
- Go easy on heavy, greasy foods, especially the first couple of days.
- Avoid things that make it worse
- Skip or strictly limit alcohol at altitude; it dehydrates you and can worsen sleep and breathing.
- Be cautious with sleeping pills and sedatives; some can depress breathing and mask symptoms.
- Dial back intense exercise for the first 1–3 days at a new high altitude; keep activities easy and steady.
Medications and planning
Acetazolamide (Diamox) and others
- Acetazolamide is a prescription medicine that helps your body acidify the blood slightly and breathe more, which speeds acclimatization.
- It’s often used preventively for people who must ascend quickly (flying into a high city, aggressive climbing itinerary, or prior history of AMS).
- Typical regimens and whether it’s appropriate for you must be decided with a clinician who knows your health history; it’s not a one‑size‑fits‑all pill.
- Other drugs (like certain lung‑pressure medicines or inhalers) are used in more specialized cases, usually under expert guidance.
Trip‑planning safety checklist
- Talk with a healthcare professional before your trip if you have heart, lung, or brain conditions, or if you’ve had altitude issues before.
- Choose itineraries that build in acclimatization days and avoid massive one‑day altitude jumps whenever possible.
- Pack a small first‑aid kit including headache medicine, nausea treatment, and any prescribed prevention meds.
- Travel with companions who are willing to turn back or stop if someone develops symptoms; “summit fever” is a known risk.
What to do if you start feeling sick
“The mountain will always be there; your job is to come back healthy enough to try again.”
- Stop going higher
- If you develop headache, nausea, unusual fatigue, or dizziness, do not ascend further until symptoms clearly improve.
- Pushing on despite symptoms is one of the biggest predictors of severe altitude illness.
- Rest, hydrate, reassess
- Rest at the same altitude, drink fluids, and eat light carbohydrates while you monitor symptoms.
- Sometimes mild AMS improves over 24 hours of rest at the same height.
- Descend if symptoms worsen or don’t improve
- If symptoms get worse, or if you notice confusion, trouble walking straight, severe shortness of breath at rest, or chest tightness, descend as soon and as safely as possible.
- In moderate to severe cases, medical care, supplemental oxygen, or pressurized rescue bags may be needed.
Quick HTML table: key prevention tips
| Strategy | What to do | Why it helps |
|---|---|---|
| Slow ascent | Limit sleeping altitude gain to ~300–500 m per day above 2,400 m; add a rest day every 900–1,000 m. | [1][5][9][3]Gives your body time to adapt to lower oxygen and reduces AMS risk. | [8][5][3]
| Climb high, sleep low | Hike higher during the day, return to a lower camp to sleep. | [7][3]Stimulates adaptation without overstressing you overnight. | [7]
| Hydration & carbs | Drink regularly, eat light, carb‑rich meals. | [5][9][1][3]Offsets fluid loss in dry air and fuels your body efficiently. | [3][5]
| Avoid alcohol & sedatives | Skip alcohol; be cautious with sleeping pills. | [9][1][7]Prevents worsened breathing, dehydration, and masked symptoms. | [9][7]
| Medication when needed | Discuss acetazolamide or other meds with a doctor if you must ascend quickly or have risk factors. | [5][7][9]Can speed acclimatization and reduce symptom risk when used correctly. | [8][7]
| Know when to turn back | Stop ascending with symptoms; descend if they worsen or don’t improve. | [1][3][5][7][9]Prevents progression to life‑threatening HACE or HAPE. | [6][8][7]