How to Handle Altitude Sickness

Altitude sickness affects more travelers than people expect. Cusco, La Paz, Tibet, the Inca Trail, Mount Kilimanjaro, parts of Colorado and Wyoming — these are common travel destinations where mild altitude symptoms are routine and serious altitude illness is a real risk if mismanaged. Understanding the protocol before going is the difference between a slow first day and a hospitalized one.

What altitude sickness actually is. At elevation, atmospheric pressure decreases, which means each breath delivers less oxygen than at sea level. Cusco at 11,150 feet (3,400 meters) has roughly 65% of the oxygen at sea level; Lhasa at 11,975 feet has 60%; the Everest Base Camp trail tops at 17,500 feet with under 50%. Your body needs 1–3 days to start producing more red blood cells to compensate. Until it does, you're operating with less oxygen than your body is used to. The symptoms — headache, fatigue, nausea, shortness of breath, loss of appetite — are the body protesting against this gap.

The three categories of altitude illness. Acute Mountain Sickness (AMS) is the mild form that affects 25–50% of travelers above 8,000 feet (2,400 m). Symptoms include headache, fatigue, mild nausea, and disturbed sleep. AMS is uncomfortable but rarely dangerous. High-Altitude Pulmonary Edema (HAPE) is fluid in the lungs — symptoms include severe shortness of breath at rest, wet cough, frothy sputum. HAPE is a medical emergency. High-Altitude Cerebral Edema (HACE) is brain swelling — symptoms include confusion, ataxia (loss of coordination), severe headache. HACE is also a medical emergency. The lethal forms are rare but real, and the only reliable treatment for severe altitude illness is descent.

Prevention protocol. Ascend gradually if possible — gain no more than 1,000 feet of sleeping elevation per day above 8,000 feet, and add a rest day every 3,000 feet of total ascent. Drink water aggressively (3+ liters per day at altitude). Skip alcohol the first 48 hours. Avoid heavy meals; eat smaller portions of carb-heavy food. Don't overexert physically the first day — the temptation to 'push through' altitude on day one is what produces the worst day-two symptoms. Acetazolamide (Diamox) is the most-prescribed prevention drug; discuss with a travel medicine doctor 4–6 weeks before the trip if your itinerary goes above 10,000 feet.

Diamox specifically. The acetazolamide protocol typically starts the day before ascent and continues 2–3 days after reaching peak altitude. It works by acidifying the blood, which stimulates increased breathing — your body adapts faster. Common side effects include tingling in the fingers and toes (mild and transient), increased urination, and a slight altered taste of carbonated drinks. It's not a magic pill; it accelerates the natural acclimatization process by 1–2 days, which is significant when your trip itself is short.

What works at elevation. Coca tea, the traditional Andean remedy, helps with mild AMS symptoms — coca leaves contain alkaloids that mildly raise blood oxygen and reduce headache. It's legal in Peru, Bolivia, and Ecuador and provided at most hotels in altitude destinations. Ibuprofen or acetaminophen for the headache. Real rest the first day — don't try to do tours or exertion the day you arrive at altitude. Sleep on the highest pillow you can manage; some travelers benefit from sleeping in a near-sitting position the first night.

When to descend. The rule: if symptoms are mild and stable, rest at the same elevation. If symptoms are worsening despite rest and hydration, descend at least 1,000 feet (300 m) immediately. If symptoms include confusion, ataxia, severe shortness of breath at rest, frothy cough, or chest pain — these are emergency signs and require immediate descent and medical attention. Descent is the only reliable treatment for severe altitude illness; medication helps with mild cases but won't fix serious ones.

Specific destinations and their altitude considerations. Cusco (11,150 ft / 3,400 m): 1–2 days acclimatization recommended before serious activity. La Paz (11,975 ft / 3,650 m): similar; the Death Road bike tour and other high-altitude excursions should wait until day 3+. The Inca Trail (peaks at 13,829 ft / 4,215 m): proper acclimatization in Cusco essential before starting; the second day is the hardest physically. Everest Base Camp (17,500 ft / 5,364 m): proper trekking program with multiple acclimatization days required. Most Colorado ski resorts (8,000–11,500 ft): mild AMS common in first-day skiers; symptoms usually resolve within 24 hours.