Introduction
Cusco sits at 3,400 meters (11,150 ft). Choquequirao at 3,050 meters. The mountain passes on our longer routes reach 4,650 meters. At these altitudes, the air has approximately 40% less oxygen than at sea level.
Your body is not designed for this—at least not immediately. Altitude sickness, known in Peru as soroche, affects a significant percentage of travelers who rise quickly above 2,500 meters. It is not a sign of weakness and has nothing to do with your physical fitness. It is simply your body’s response to an environment it wasn’t prepared for.
This guide explains what altitude sickness is, how to prevent it, and what to do if it affects you during your trek.
What is Altitude Sickness?
When you ascend, atmospheric pressure drops, meaning there are fewer oxygen molecules in every breath. To compensate, your body breathes faster, your heart beats quicker, and you produce more red blood cells.
These adjustments take time. If you ascend faster than your body can adapt, you develop Acute Mountain Sickness (AMS), commonly known as altitude sickness.
Altitude Risk Levels
Altitude | Risk Level | Examples |
0 – 1,500 m | None | Lima, coastal cities |
1,500 – 2,500 m | Low | Arequipa (2,335 m) |
2,500 – 3,500 m | Moderate | Cusco (3,400 m), Choquequirao (3,050 m) |
3,500 – 4,500 m | High | High-altitude campsites |
Over 4,500 m | Very High | San Juan Pass (4,650 m) |
Who is at Risk?
Anyone. Altitude sickness does not discriminate. We have seen marathon athletes struggle while sedentary retirees feel perfect.
- Factors that DO NOT predict risk: Fitness, age, gender, or weight.
- Factors that DO increase risk: Rapid ascent, dehydration, alcohol consumption, and a history of severe altitude sickness.
Recognizing the Symptoms
1. Mild Symptoms (Common)
Affects 25-50% of travelers in Cusco.
- Headache (the most frequent sign)
- Unusual fatigue or dizziness
- Difficulty sleeping
- Loss of appetite or mild nausea
- What to do: Rest, hydrate (3-4 liters of water), take over-the-counter painkillers (ibuprofen), and avoid alcohol. Symptoms usually improve within 12-48 hours.
2. Moderate Symptoms (Requires Attention)
- Severe headache that doesn’t respond to painkillers
- Persistent nausea or vomiting
- Extreme fatigue (difficulty standing up)
- Shortness of breath at rest
- What to do: Stop ascending immediately. Inform your guide. Consider descending 300-500 meters. Use supplemental oxygen if available.
3. Severe Symptoms (Emergency)
Rare at these altitudes but dangerous.
- HACE (Cerebral Edema): Confusion, behavior changes, loss of coordination (ataxia).
- HAPE (Pulmonary Edema): Extreme difficulty breathing, persistent cough with pinkish sputum, blue-tinted lips (cyanosis).
- What to do: Immediate descent. This is a life-or-death emergency. Our guides are trained to initiate evacuation protocols instantly.
Prevention Strategies
- Gradual Ascent: Arrive in Cusco at least 48 hours (ideally 72) before your trek. Spend your first day resting.
- Hydration: Altitude dehydrates you quickly. Drink 3-4 liters of water daily. Clear urine is the best sign that you are well-hydrated.
- Light Meals: Stick to complex carbohydrates (rice, pasta, quinoa) and avoid heavy, greasy foods that slow down digestion.
- Preventative Medication: * Acetazolamide (Diamox): The most effective medication for prevention. It speeds up acclimatization. (Consult your doctor before use).
- Ibuprofen: Can help prevent altitude-induced headaches.
- Coca Leaves: A traditional Andean remedy. While not scientifically proven to prevent AMS, chewing leaves or drinking mate de coca provides subjective relief for many.
Myths vs. Truths
- Myth: “Fitness protects you.” It affects everyone equally.
- Myth: “Oxygen cures it.” It only relieves symptoms temporarily; it doesn’t speed up acclimatization.
- Truth: “Descending is the best treatment.” A descent of just 300-500 meters can produce dramatic improvement.
- Truth: “Climb high, sleep low.” This is the golden rule of mountaineering that we incorporate into our route designs.
Altitude Safety on Our Tours
We don’t just hope for the best; we prepare for the worst. Our expeditions include:
- Portable supplemental oxygen in every group.
- Pulse oximeters to monitor oxygen saturation levels.
- WFR-certified guides (Wilderness First Aid) trained in altitude protocols.
- Satellite communication for emergency evacuations in remote areas.
FAQ
- Should I take Diamox? If you have limited time to acclimate or a history of AMS, it may help. Consult your physician.
- Can altitude sickness be fatal? Only in severe, untreated cases (HAPE/HACE). With proper awareness and a professional guide, it is almost entirely manageable.
- Does alcohol make it worse? It dehydrates you and can mask or worsen symptoms. Avoid it for your first 48 hours in Cusco.
Conclusion
Altitude sickness is a reality of trekking in the Andes, but it shouldn’t be feared—just respected. By arriving early, staying hydrated, and being honest with your guide about how you feel, it will be nothing more than a minor hurdle on your way to Choquequirao.
Have questions about the altitude? Our team is here to help you prepare based on your personal health history.
