Is altitude sickness dangerous?

Mild altitude sickness (headache, fatigue) is uncomfortable but not dangerous. Severe cases—high altitude cerebral edema (HACE) or high altitude pulmonary edema (HAPE)—are medical emergencies requiring immediate descent. These are rare with gradual ascent but can develop in 6-12 hours. Descent cures both.

Can you prevent altitude sickness completely?

Not always. You can reduce risk by ascending slowly, staying hydrated, and using acetazolamide, but susceptibility varies by individual and can't be predicted beforehand. Some people have no symptoms at 10,000 feet; others struggle at 6,000 feet. Fitness level doesn't protect you—elite athletes get altitude sickness.

How high is 'high altitude'?

Altitude sickness typically starts around 8,000 feet (2,400 meters). Risk increases significantly above 12,000 feet. Denver (5,280 feet) causes mild symptoms in some people. Mexico City (7,380 feet) affects 30-50% of visitors. La Paz, Bolivia (11,975 feet) affects most newcomers.

Should I take acetazolamide if I have mild symptoms?

If you have a headache and mild fatigue but can still function, skip it initially. Rest and hydration often resolve symptoms within 24 hours. Start acetazolamide if symptoms are moderate, persistent after 24 hours, or if you need to ascend higher quickly. Take it as prescribed—stopping mid-course is less effective.

Is oxygen helpful at altitude?

Supplemental oxygen helps temporarily (usually 1-2 hours per bottle) but is expensive, bulky, and impractical for travelers. It masks symptoms without treating the underlying problem. Descent is the actual solution. Oxygen makes sense in emergency situations or for severe HAPE/HACE, not for typical altitude sickness.

Can you become accustomed to altitude over time?

Yes, but only partially. Your body produces more red blood cells and adjusts oxygen processing within 3-4 days. However, some symptoms linger longer at very high elevations (above 14,000 feet). Spending weeks at altitude improves acclimatization but doesn't eliminate all effects.

Will going down to sleep altitude and up during the day help?

Yes, if available. This is called 'climb high, sleep low.' Sleep at lower elevations (where your body processes oxygen better) and hike or work at higher elevations during the day. It speeds acclimatization. This isn't always logistically possible but works well for mountaineers and trekkers.

How to Deal With Altitude Sickness While Traveling

Altitude sickness happens when you ascend too quickly and your body lacks oxygen. The best treatment is slow acclimatization—ascending gradually, staying hydrated, resting, and descending if symptoms worsen. Most cases resolve within 24-48 hours at a stable altitude.

Recognize the symptoms early. Altitude sickness typically hits within 2-24 hours of arrival. Watch for headache, nausea, fatigue, and shortness of breath. Mild cases feel like a hangover. Severe cases involve confusion, difficulty walking, or extreme breathlessness—these require immediate descent.
Ascend slowly if possible. If you have control over your itinerary, don't jump to high altitude immediately. Spend 1-2 days at intermediate elevations (5,000-8,000 feet) before going higher. Every 1,000 feet of elevation gain matters. Flying into Denver (5,280 feet) is manageable. Flying into La Paz (11,975 feet) is rough.
Stay hydrated aggressively. Drink 3-4 liters of water per day at altitude, even if you don't feel thirsty. Altitude dehydrates you faster. Avoid alcohol and caffeine for the first 48 hours—they worsen dehydration and symptoms. Electrolyte drinks help more than plain water.
Rest for the first 24-48 hours. Don't plan strenuous activities on your first day. Your body is working overtime to process oxygen. Sleep extra, move slowly, and give yourself permission to do nothing. Most symptoms fade naturally with rest and time.
Eat carbohydrate-heavy meals. Your body burns more calories at altitude and processes carbs more efficiently than fats or proteins. Eat pasta, rice, bread, and potatoes. Skip heavy, greasy foods. Eat frequent small meals rather than one large one.
Use medication if symptoms are moderate to severe. Acetazolamide (Diamox) is the standard prevention and treatment drug. Take 125-250 mg twice daily starting 24 hours before ascent and continuing for 2-3 days. It reduces symptoms by 50% and speeds acclimatization. Get a prescription before your trip—it's not available everywhere. Ibuprofen helps headaches. Don't use sedatives, which reduce your breathing rate and worsen altitude sickness.
Descend if symptoms are severe or worsening. If you have confusion, severe shortness of breath at rest, or inability to walk straight after 24 hours, descend at least 1,000-3,000 feet immediately. These are signs of high altitude cerebral edema (HACE), a medical emergency. Descent is the only proven treatment for severe cases.
Acclimatize over multiple days at the same elevation. Once you reach your target altitude, stay there for 3-4 days without going higher. Your body produces more red blood cells and adjusts oxygen processing. After 3-4 days, most people feel nearly normal. Only then plan higher activities or ascents.

Is altitude sickness dangerous?: Mild altitude sickness (headache, fatigue) is uncomfortable but not dangerous. Severe cases—high altitude cerebral edema (HACE) or high altitude pulmonary edema (HAPE)—are medical emergencies requiring immediate descent. These are rare with gradual ascent but can develop in 6-12 hours. Descent cures both.
Can you prevent altitude sickness completely?: Not always. You can reduce risk by ascending slowly, staying hydrated, and using acetazolamide, but susceptibility varies by individual and can't be predicted beforehand. Some people have no symptoms at 10,000 feet; others struggle at 6,000 feet. Fitness level doesn't protect you—elite athletes get altitude sickness.
How high is 'high altitude'?: Altitude sickness typically starts around 8,000 feet (2,400 meters). Risk increases significantly above 12,000 feet. Denver (5,280 feet) causes mild symptoms in some people. Mexico City (7,380 feet) affects 30-50% of visitors. La Paz, Bolivia (11,975 feet) affects most newcomers.
Should I take acetazolamide if I have mild symptoms?: If you have a headache and mild fatigue but can still function, skip it initially. Rest and hydration often resolve symptoms within 24 hours. Start acetazolamide if symptoms are moderate, persistent after 24 hours, or if you need to ascend higher quickly. Take it as prescribed—stopping mid-course is less effective.
Is oxygen helpful at altitude?: Supplemental oxygen helps temporarily (usually 1-2 hours per bottle) but is expensive, bulky, and impractical for travelers. It masks symptoms without treating the underlying problem. Descent is the actual solution. Oxygen makes sense in emergency situations or for severe HAPE/HACE, not for typical altitude sickness.
Can you become accustomed to altitude over time?: Yes, but only partially. Your body produces more red blood cells and adjusts oxygen processing within 3-4 days. However, some symptoms linger longer at very high elevations (above 14,000 feet). Spending weeks at altitude improves acclimatization but doesn't eliminate all effects.
Will going down to sleep altitude and up during the day help?: Yes, if available. This is called 'climb high, sleep low.' Sleep at lower elevations (where your body processes oxygen better) and hike or work at higher elevations during the day. It speeds acclimatization. This isn't always logistically possible but works well for mountaineers and trekkers.