At a glance
Altitude illness is not about fitness. It is mainly about ascent speed and sleeping altitude. Mild symptoms are common in the first 24–48 hours. Severe illness is rare, but it is predictable and preventable with the right rules.
1) Recognise early symptoms.
2) Do not go higher to sleep if symptoms are present.
3) If symptoms worsen at the same altitude, descend.
The goal is not “zero symptoms.” The goal is to keep symptoms mild and protect the itinerary: stable sleep, stable pacing, and a route that can step down if needed.
This page is general travel guidance, not personal medical advice. If you have heart or lung disease, sleep apnea, pregnancy, or previous severe altitude illness, speak with a clinician before committing to a high-altitude route.
Altitude map (key elevations)
Knowing the numbers helps you understand why some days feel easy and others feel sharp. In Uyuni, the challenge is cumulative exposure over nights.
Common starting points
- San Pedro de Atacama: ~2,400 m
- Tupiza: ~2,850 m
- La Paz: ~3,650 m (El Alto airport ~4,061 m)
- Uyuni town: ~3,700 m
Typical high points on South Lipez routes
- Salar de Uyuni: ~3,656 m
- Laguna Colorada: ~4,278 m
- Laguna Verde: ~4,310 m
- Hito Cajón / Portezuelo del Cajón: ~4,480 m
- Sol de Mañana area: ~4,850 m
Your highest point is not always the problem. Your highest sleeping altitude and the speed of ascent are usually the drivers.
Who is at risk
Susceptibility varies between people and does not correlate reliably with strength or endurance. What increases risk is arriving high, sleeping high, and pushing effort early.
Higher-risk patterns
- Rapid ascent from low altitude to 3,500–4,000 m with no buffer night.
- Going higher to sleep while symptomatic.
- Hard exertion on day one (fast hikes, long walks on the salt, heavy alcohol use).
- History of AMS, HACE, or HAPE on previous trips.
Conditions that warrant clinician input
- Chronic lung disease, heart disease, pulmonary hypertension.
- Significant sleep apnea or baseline low oxygen saturation.
- Pregnancy, severe anemia, or complex medication profiles.
- Anyone considering prescription prevention (e.g., acetazolamide).
Acclimatization strategy
Good acclimatization is boring by design. It is controlled ascent, controlled effort, and predictable sleep. Once you are above ~3,000 m, your plan should prioritise sleeping altitude and recovery.
Simple framework
- When possible, stage your ascent with an intermediate night.
- Keep day one light. Let your first night do the work.
- Do not “push through” worsening symptoms. Stop, stabilise, or descend.
How this looks on real routes
- Arriving via San Pedro: you start moderate (2,400 m) and step up. Good for many travellers.
- Arriving via Tupiza: often the calmest build-up before entering the higher reserves.
- Arriving via La Paz: you may start very high immediately. A rest day is often wise before long drives south.
Why the first night matters
Acute mountain sickness often begins within hours after arrival and commonly shows up during or after the first night. The smartest “treatment” is to avoid stacking effort and altitude on top of that first sleep window.
Symptoms and red flags
Early altitude illness can feel like a hangover: headache plus fatigue, nausea, dizziness, or poor appetite. The risk is not discomfort. The risk is ignoring progression.
Typical mild AMS
- Headache (the key symptom), fatigue, light dizziness.
- Nausea or reduced appetite.
- Poor sleep, unusual breathing patterns at night.
Rest. Reduce effort. Do not ascend to a higher sleep. If symptoms improve, the itinerary continues calmly.
Red flags (treat as urgent)
- Confusion, loss of coordination, inability to walk a straight line (possible HACE).
- Shortness of breath at rest, cough, chest tightness, frothy sputum (possible HAPE).
- Symptoms getting worse despite rest at the same altitude.
Stop ascent. Descend. Seek medical evaluation. Oxygen and medications can help, but they should not delay descent when severe symptoms are present.
Medication and oxygen
Medications can support acclimatization, but they do not replace planning. The primary prevention is staged ascent. The primary treatment for worsening illness is descent.
Acetazolamide (Diamox)
- Used for prevention and to speed acclimatization.
- Typical adult prevention dose is often 125 mg twice daily, started the day before ascent (clinical guidance varies by individual).
- Discuss suitability with a clinician—especially if pregnant, with kidney issues, or with complex allergies.
Oxygen and emergency medication
- Supplemental oxygen can improve symptoms, where available.
- Some travellers carry clinician-prescribed emergency medication (e.g., dexamethasone) for remote routes.
- For severe symptoms, these are adjuncts. Descent remains the priority.
Sleep disruption is common at altitude. Avoid using alcohol or sedatives to “force sleep” in the first nights. If you need sleep support, discuss safer options with a clinician in advance.
Should I bring a pulse oximeter?
It can be useful as a trend indicator, but it does not replace symptom awareness. People can have “okay numbers” and still feel unwell, and vice versa. We treat symptoms and function as the decision drivers.
How we design the itinerary
Our job is to build a route that respects altitude as a constraint. That means controlling the first 48 hours, controlling sleeping altitude when possible, and keeping a descent option in the structure.
What we prioritise
- Clean pacing on day one: fewer “extra stops,” more controlled effort.
- Early departures in the high zones to avoid rushed, late-day fatigue.
- A coherent route that does not require last-minute improvisation.
- Clear decision points: continue, stabilise, or step down.
Why dry season helps here
- Route reliability reduces stress and rushed driving.
- Stable tracks make it easier to keep sleep and arrival times predictable.
- Crossing to San Pedro (2,400 m) can act as a meaningful descent after high days.
On South Lipez routes, discomfort usually comes from cumulative exposure: cold nights, wind, and long drives at altitude. A well-built itinerary does not pretend this is easy. It keeps it manageable.
Day-to-day habits that help
Small behaviours have outsized impact at 3,700–4,800 m. The goal is to lower workload on the body while it adapts.
First 24–48 hours
- Eat lightly and regularly, even if appetite drops.
- Hydrate steadily (no extremes).
- Avoid alcohol early. It disrupts sleep and breathing.
- Keep exertion moderate: short walks, slow pace, no sprinting for photos.
Ongoing
- Protect sleep: warm layers, wind control, consistent bedtime.
- Keep mornings calm. Headache often improves after you are moving and warmed up.
- Speak up early if symptoms change. Delay creates escalation.
What about “natural remedies”?
Many local and traveller practices exist. We treat them as comfort measures, not prevention. If symptoms progress, the response is operational: stop ascent, stabilise, descend if needed.
Packing notes
Altitude discomfort is often amplified by cold and dehydration. Pack to control exposure first, then add small items that make the first days easier.
Core layers
- Windproof shell (non-negotiable in open terrain).
- Warm mid-layer + base layer (easy to adjust during drives).
- Hat and gloves (morning starts in South Lipez are cold).
Support items
- Sunglasses and sunscreen (glare is strong on salt and snow-dust).
- Lip balm and moisturiser (wind + dry air).
- Simple snacks you can tolerate when appetite is low.
- Any clinician-recommended prescriptions in original packaging.
If you plan to use prescription prevention, organise it before travel. Remote routes are not the place to improvise dosing or discover contraindications.
Common questions
How long does acclimatization take?
Mild symptoms often resolve within 12–48 hours if you do not ascend further. Some people take longer, especially if sleep is poor or the itinerary climbs quickly.
Can I do a 3-day Uyuni → Atacama route without acclimatizing?
Some travellers can. Many feel it. The route reaches very high points quickly. If you are coming from sea level, a buffer night (or a staged approach via an intermediate altitude) is often the difference between managing and suffering.
Should everyone take acetazolamide (Diamox)?
No. It is not automatically needed for every traveller. It is most useful when ascent is rapid, when a person has prior AMS history, or when the itinerary has limited flexibility. Discuss personal suitability with a clinician.
What is the clearest sign we need to descend?
Symptoms that worsen despite rest at the same altitude, or any red flags: confusion, loss of coordination, or breathlessness at rest. In those cases, descent is the priority.