At what elevation does altitude sickness start?

Most people start experiencing symptoms above 8,000 feet (2,400m). Cusco sits at 11,200 feet, La Paz at 11,975 feet, and Quito at 9,350 feet - all high enough to cause problems for most travelers.

How long does it take to acclimatize?

Initial acclimatization takes 2-3 days for most people. Full acclimatization to high altitude takes 1-2 weeks. You'll feel significantly better after 48-72 hours if you follow proper protocols.

Can I exercise or hike during acclimatization?

Stick to light walking for the first 2-3 days. Avoid strenuous hikes, gym workouts, or climbing stairs quickly until symptoms subside. Your heart rate will be elevated even during normal activities.

Do altitude sickness pills really work?

Acetazolamide (Diamox) is clinically proven to reduce symptoms by 40-50% when taken properly. It's not a cure but significantly helps acclimatization. Always get it prescribed by a doctor who knows your medical history.

What's the difference between mild and dangerous altitude sickness?

Mild symptoms are headache, nausea, and fatigue that improve with rest and hydration. Dangerous symptoms include confusion, severe headache with vomiting, difficulty walking straight, or breathing problems - these require immediate descent.

How to Handle Altitude Sickness in Andean Cities

Arrive 2-3 days early, drink 3-4 liters of water daily, avoid alcohol, and ascend gradually. Take acetazolamide if prescribed by your doctor. Most symptoms resolve within 48-72 hours as your body acclimates to elevations above 8,000 feet.

Start prevention before you travel. Get acetazolamide (Diamox) prescribed by your doctor 2-3 weeks before departure. Take 125mg twice daily starting 1-2 days before arriving at altitude. This helps your body produce more red blood cells and breathe more efficiently.
Hydrate aggressively from day one. Drink 3-4 liters of water daily, even if you don't feel thirsty. Your body loses water faster at altitude through increased breathing and urination. Carry a 1-liter water bottle and refill it 3-4 times daily. Avoid alcohol for the first 48 hours.
Plan a gradual ascent when possible. If flying directly to cities above 10,000 feet (like Cusco or La Paz), build in 2-3 rest days before any strenuous activity. If driving, stop overnight at intermediate elevations. Don't gain more than 2,000 feet of sleeping elevation per day above 8,000 feet.
Recognize the warning signs. Mild symptoms include headache, nausea, fatigue, and difficulty sleeping. These are normal and usually improve within 2-3 days. Severe symptoms requiring immediate descent include confusion, difficulty walking, severe headache that doesn't respond to painkillers, or fluid in lungs (crackling sounds when breathing).
Manage symptoms as they appear. For headaches, take ibuprofen or acetaminophen every 6-8 hours. Eat light, high-carb meals even if you're not hungry. Rest frequently and avoid overexertion for the first 2-3 days. Sleep with your head elevated if possible.
Know when to descend immediately. If you experience severe headache with vomiting, confusion, loss of coordination, or breathing difficulties, descend at least 1,000-2,000 feet immediately. Don't wait for symptoms to worsen. Seek medical attention in the nearest major city.

At what elevation does altitude sickness start?: Most people start experiencing symptoms above 8,000 feet (2,400m). Cusco sits at 11,200 feet, La Paz at 11,975 feet, and Quito at 9,350 feet - all high enough to cause problems for most travelers.
How long does it take to acclimatize?: Initial acclimatization takes 2-3 days for most people. Full acclimatization to high altitude takes 1-2 weeks. You'll feel significantly better after 48-72 hours if you follow proper protocols.
Can I exercise or hike during acclimatization?: Stick to light walking for the first 2-3 days. Avoid strenuous hikes, gym workouts, or climbing stairs quickly until symptoms subside. Your heart rate will be elevated even during normal activities.
Do altitude sickness pills really work?: Acetazolamide (Diamox) is clinically proven to reduce symptoms by 40-50% when taken properly. It's not a cure but significantly helps acclimatization. Always get it prescribed by a doctor who knows your medical history.
What's the difference between mild and dangerous altitude sickness?: Mild symptoms are headache, nausea, and fatigue that improve with rest and hydration. Dangerous symptoms include confusion, severe headache with vomiting, difficulty walking straight, or breathing problems - these require immediate descent.