Altitude Sickness in Peru: Symptoms, Prevention, and What to Do
Cusco sits at 3,400 m (11,150 ft). Most first-time visitors experience some altitude symptoms. Here is what to expect, how to prevent it, and when to be concerned.
By the Travel Smart Peru editorial team · Last updated April 2026 · 14 min read
Last updated: April 2026
Affiliate disclosure: Some links on Travel Smart Peru may be affiliate links. If you book through these links, we may earn a commission at no extra cost to you. We only include links that are relevant to the guide and useful for travelers. Learn more
What Is Altitude Sickness?
Altitude sickness — medically called Acute Mountain Sickness (AMS) — occurs when you ascend to high altitude faster than your body can adapt. At altitude, the air contains less oxygen per breath. Your body responds by breathing faster and producing more red blood cells, but this adjustment takes time. If you ascend too quickly, you may develop symptoms ranging from a mild headache to, in rare cases, life-threatening conditions.
In Peru, altitude sickness is most commonly encountered in Cusco (3,400 m), the Sacred Valley (2,800–3,000 m), and Puno near Lake Titicaca (3,812 m). Rainbow Mountain (5,200 m) is only suitable for visitors who have already fully acclimatized.
The local term is soroche. Peruvians are well aware of it and hotels, restaurants, and tour operators in Cusco routinely offer coca tea and other remedies. You will not be the first person to ask for help.
Altitude Levels Across Peru
Not all of Peru is high altitude. Lima is at sea level. Machu Picchu is at a moderate altitude that most people tolerate well. The highest-risk destinations are Cusco, Puno, and any high-altitude hikes.
| Location | Altitude | AMS Risk |
|---|---|---|
| Lima | 154 m / 505 ft | None |
| Paracas / Ica | ~10 m / 33 ft | None |
| Machu Picchu | 2,430 m / 7,970 ft | Low |
| Ollantaytambo | 2,792 m / 9,160 ft | Low–Moderate |
| Pisac / Sacred Valley | ~2,950 m / 9,680 ft | Moderate |
| Cusco | 3,400 m / 11,150 ft | Moderate–High |
| Lake Titicaca (Puno) | 3,812 m / 12,507 ft | High |
| Rainbow Mountain | 5,200 m / 17,060 ft | Very High |
Symptoms: Mild to Severe
Altitude sickness exists on a spectrum. The vast majority of cases are mild and resolve with rest and hydration. Severe forms — High Altitude Cerebral Edema (HACE) and High Altitude Pulmonary Edema (HAPE) — are rare but life-threatening and require immediate descent.
Symptoms: Headache, fatigue, dizziness, shortness of breath, poor sleep, loss of appetite, nausea
What to do: Rest, hydrate, take ibuprofen. Do not ascend further until symptoms resolve.
Symptoms: Persistent headache not relieved by medication, vomiting, increasing fatigue, difficulty with physical tasks
What to do: Rest completely. Consider descending 300–500 m. Consult a doctor if symptoms persist beyond 24 hours.
Symptoms: Confusion, loss of coordination (ataxia), severe headache, altered consciousness
What to do: Medical emergency. Descend immediately. Administer supplemental oxygen if available. Seek emergency medical care.
Symptoms: Extreme breathlessness at rest, cough (may produce pink frothy sputum), blue lips or fingertips, inability to walk
What to do: Medical emergency. Descend immediately. This condition can be fatal. Seek emergency medical care.
Prevention: Before You Arrive
The most effective prevention strategies begin before you board the plane to Cusco.
Talk to your doctor about Diamox
Acetazolamide (brand name Diamox) is a prescription medication that accelerates acclimatization by stimulating faster breathing. It is the most evidence-based pharmacological prevention for AMS. The standard prophylactic dose is 125–250 mg twice daily, starting 1–2 days before ascent and continuing for 2 days at altitude.
Diamox is not suitable for everyone. It should not be taken by people with sulfa allergies, and it can cause increased urination and tingling in the extremities. Consult your doctor or a travel medicine clinic before your trip.
Arrive well-rested
Fatigue significantly worsens altitude sickness. If possible, avoid red-eye flights that arrive in Cusco early in the morning after a sleepless night. Arrive rested and plan to rest further on arrival day.
Avoid alcohol before your flight
Alcohol dehydrates you and impairs your body's ability to acclimatize. Avoid it for at least 24 hours before your flight to Cusco.
Prevention: Once You Arrive in Cusco
The first 24 hours in Cusco are the most important. What you do — and do not do — in this window has a significant impact on how you feel for the rest of your trip.
Before you travel
- 1
Consult your doctor about Diamox (acetazolamide) — a prescription medication that helps prevent altitude sickness.
- 2
If you have heart or lung conditions, get medical clearance before traveling to high altitude.
- 3
Avoid alcohol for 24 hours before your flight to Cusco.
- 4
Arrive well-rested. Fatigue makes altitude sickness worse.
On arrival in Cusco
- 1
Rest for the first 4–6 hours. Do not schedule tours or strenuous activities on arrival day.
- 2
Drink 2–3 liters of water throughout the day. Dehydration worsens symptoms.
- 3
Eat light meals. Heavy, rich food is harder to digest at altitude.
- 4
Avoid alcohol for at least the first 24–48 hours.
- 5
Drink coca tea — available at most hotels and restaurants.
- 6
Take ibuprofen or paracetamol for headaches if needed.
During your stay
- 1
Ascend gradually. Do not go to Rainbow Mountain or Vinicunca on your first day in Cusco.
- 2
Sleep at a lower altitude if possible — the Sacred Valley (Ollantaytambo or Pisac) is 600 m lower than Cusco.
- 3
Listen to your body. Mild symptoms are normal. Severe symptoms (confusion, loss of coordination, persistent vomiting) require descent.
- 4
Stay hydrated throughout your trip.
Recommended Acclimatization Schedule
The golden rule of altitude acclimatization is: "climb high, sleep low." You can visit higher altitudes during the day, but sleep at a lower elevation to allow your body to recover. Here is a practical schedule for a first-time visitor to Peru:
Medications: Diamox, Coca, and Other Remedies
Diamox (Acetazolamide)
Diamox is the most effective pharmacological prevention for altitude sickness. It works by making the blood slightly more acidic, which stimulates faster breathing and speeds up acclimatization. It is a prescription medication — ask your doctor or a travel medicine clinic before your trip.
| Category | Taking Diamox | Not taking Diamox |
|---|---|---|
| Acclimatization speed | ✓Faster | Normal body pace |
| AMS prevention | ✓Significantly reduced risk | Higher risk on rapid ascent |
| Side effects | Increased urination, tingling, mild diuresis | ✓None from medication |
| Suitability | Not for sulfa allergy; requires prescription | ✓Suitable for everyone |
| Best for | Rapid ascent, tight itineraries, high-risk individuals | Slow ascent, extra rest days |
Coca Tea (Mate de Coca)
Coca leaves contain small amounts of alkaloids that may provide mild relief from altitude symptoms. Coca tea is widely available in Cusco — your hotel will likely offer it on arrival. It is legal in Peru (and throughout the Andean region) and has been used by indigenous communities for centuries.
Coca tea is not a substitute for proper acclimatization, but many travelers find it helpful for mild headaches and nausea. The alkaloid content in a cup of tea is very low — far below any level of concern.
Ibuprofen and Paracetamol
For mild altitude headaches, ibuprofen (400–600 mg) is effective and well-tolerated. Paracetamol (acetaminophen) is an alternative. These are symptomatic treatments — they address the headache but do not treat the underlying cause. If headaches persist beyond 24 hours despite rest and medication, take it seriously.
Dexamethasone
Dexamethasone is a corticosteroid used for treatment of severe AMS and HACE. It is not a preventative medication and should only be used in emergency situations. It is prescription-only. Some travelers carry it as an emergency backup — discuss this with your doctor.
Treatment If You Get Altitude Sickness
If you develop altitude sickness symptoms, here is what to do:
For mild symptoms
- •Stop ascending. Do not go to higher altitude until symptoms resolve.
- •Rest completely for 24 hours.
- •Drink 2–3 liters of water.
- •Take ibuprofen (400 mg) or paracetamol for headache.
- •Drink coca tea.
- •Eat light, easily digestible food.
- •Avoid alcohol and sleeping pills.
For moderate symptoms (not improving after 24 hrs)
- •Descend 300–500 m immediately. Even a small descent can produce rapid improvement.
- •Consider taking Diamox if you have it and have not already started.
- •Seek medical attention in Cusco — there are clinics experienced with altitude sickness.
- •Do not ascend again until fully recovered.
For severe symptoms (HACE or HAPE) — Medical Emergency
- !Descend immediately — this is the single most important action.
- !Administer supplemental oxygen if available.
- !Call for emergency medical assistance.
- !Do not leave the person alone.
- !Dexamethasone (8 mg initial dose) can be used for HACE if available and the person is conscious.
- !HAPE requires supplemental oxygen and immediate descent — it can be fatal within hours.
Who Is Most at Risk?
Altitude sickness does not follow predictable patterns, but certain factors increase the likelihood of a difficult acclimatization:
Flying directly from sea level to Cusco is the most common risk factor. The faster you ascend, the less time your body has to adapt.
If you have had altitude sickness before, you are more likely to experience it again at similar altitudes.
Dehydration worsens AMS symptoms. Drink more water than you think you need.
Alcohol impairs acclimatization and worsens symptoms. Avoid it for the first 48 hours at altitude.
Strenuous activity on arrival day dramatically increases AMS risk. Rest is not optional.
Heart or lung conditions, anemia, and sleep apnea can increase risk. Consult your doctor before traveling to high altitude.
Altitude and Itinerary Order
The order in which you visit Peru's destinations has a significant impact on your altitude experience. The standard recommended order for first-time visitors is:
For a detailed day-by-day itinerary that accounts for altitude, see our Peru 10-Day Itinerary and How Many Days in Cusco Before Machu Picchu.
Frequently Asked Questions
Related Guides
Get the Peru First-Time Visitor Checklist
What to book, when to book it, and common mistakes to avoid — free.
No spam. Unsubscribe anytime.
Affiliate disclosure: Some links on Travel Smart Peru may be affiliate links. If you book through these links, we may earn a commission at no extra cost to you. We only include links that are relevant to the guide and useful for travelers. Learn more
Medical disclaimer: The information on this page is for general travel planning purposes only and does not constitute medical advice. Consult a qualified healthcare professional or travel medicine clinic before traveling to high altitude, particularly if you have pre-existing health conditions.