Altitude Sickness Guide

Prevention, symptoms, and acclimatization for high-altitude hiking

Medical Disclaimer: This guide is for informational purposes only and is not medical advice. Consult a healthcare provider before traveling to high altitude, especially if you have pre-existing conditions.

Symptom Checker

Types

Prevention

Acclimatization

Mild

AMS - Acute Mountain Sickness

Most common form. Occurs above 8,000 ft (2,500 m). Symptoms: headache plus nausea, fatigue, dizziness, or insomnia.

Onset: 6-12 hours after arrival at altitude
Treatment: Rest, hydrate, ibuprofen for headache. Do not ascend until symptoms resolve.
Most people acclimatize in 1-3 days

Moderate

HACE - High Altitude Cerebral Edema

Brain swelling. Can develop from untreated AMS. Occurs above 12,000 ft (3,600 m).

Key signs: Confusion, ataxia (can't walk straight), altered consciousness
Treatment: IMMEDIATE descent. Dexamethasone. Supplemental oxygen.
Can be fatal within 24 hours if untreated

Severe

HAPE - High Altitude Pulmonary Edema

Fluid in lungs. Most dangerous common form. Above 8,000 ft (2,500 m).

Key signs: Breathlessness at rest, persistent cough, gurgling breath, blue lips
Treatment: IMMEDIATE descent. Nifedipine. Supplemental oxygen. Portable hyperbaric chamber.
Leading cause of altitude-related deaths

Prevention Guidelines

Ascend gradually: Above 10,000 ft, gain no more than 1,000 ft of sleeping altitude per day
Rest days: Take a rest day every 3,000 ft of elevation gain
Climb high, sleep low: Day hike to higher elevations but sleep at a lower camp
Hydrate: Drink 3-4 liters of water per day at altitude
Avoid alcohol for the first 48 hours at a new altitude
Eat carbohydrates: High-carb diet is easier to digest at altitude
Medication: Acetazolamide (Diamox) 125mg twice daily, starting 24h before ascent
Know your limits: Previous altitude sickness increases future risk

Acclimatization Schedule