What Are Symptoms of Altitude Sickness?

The cause of altitude sickness is gaining altitude too quickly, which doesn't allow the body enough time to adjust to reduced oxygen and changes in air pressure. This results in a lack of oxygen reaching the tissues of the body.

Physical fitness does not decrease a person’s chances of developing a high-altitude illness. While it is not always possible to know in advance who may become ill when traveling to a high altitude, certain groups are at increased risk, such as people who:

• Have a prior history of altitude sickness
• Overexert themselves before adjusting to the change in altitude
• Ascend rapidly (e.g., within one day) from low elevation to altitudes above 9,000 ft/2,750 m
• Ascend rapidly (more than 1,640 to 3,280 ft/day [more than 500 to 1000 m/day] in sleeping altitude), when already above 9,000 ft/2,750 m
• Have an underlying medical condition that affects breathing

Symptoms of altitude sickness generally resolve within 12 to 48 hours of acclimatization at elevation. 

Treatment for altitude sickness includes: 

• Rest
• Stop ascent for at least 24 to 48 hours
• Medications 
  • For headache
    • Nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen (Advil, Motrin) or naproxen (Aleve) 
    • Acetaminophen (Tylenol)
  • For nausea
    • Ondansetron (Zofran)
    • Promethazine (Phenergan, Promethegan, Phenadoz)
  • To reduce severity of symptoms (though it will not get rid of them completely)
    • Acetazolamide (Diamox)
• Drink plenty of water
• Do not smoke, drink alcohol, or exercise
• Tell travel companions how you feel, even if symptoms are mild because there's danger your judgement may not be clear
• Do not attempt to climb again until symptoms have completely gone away
• If you do not feel better after 24 hours, descend by at least 1,600 feet/500 meters

See a doctor if symptoms do not improve or worsen.

Treatment for high altitude cerebral edema (HACE) includes:

• Descent to a lower altitude immediately
• Dexamethasone to reduce brain swelling (often carried by professional mountain climbers as part of their medical supplies)
• Bottled oxygen, if available
• Seek medical treatment at a hospital as soon as possible for follow-up treatment

Treatment for high altitude pulmonary edema (HAPE) includes:

• Descent to a lower altitude immediately
• Nifedipine (Procardia XL, Adalat CC, Afeditab CR) to reduce chest tightness and make breathing easier (often carried by professional mountain climbers as part of their medical supplies)
• Bottled oxygen, if available
• Seek medical treatment at a hospital as soon as possible for follow-up treatment

The best way to prevent altitude sickness is to travel to high altitudes slowly. It usually takes 12 to 48 hours at elevation for the body to get used to a change in altitude.

In addition: 

• When possible, avoid flying directly to areas of high altitude
• Allow two to three days to acclimate to high altitudes before going above 8,000 feet
• Don’t climb more than 1,000 feet to 1,600 feet per day
• Include a rest day every 2,000 feet to 3,000 feet you climb, or rest every three to four days
• Drink plenty of water
• Don’t smoke or drink alcohol
• Avoid strenuous exercise for the first 24 hours
• Eat a light but high-calorie diet
• Travelling with these medicines for altitude sickness:
  • Acetazolamide (Diamox) to prevent and treat high-altitude sickness
    • Begin taking one to two before starting to climb and continue to take it while going up
  • Nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen (Advil, Motrin) or naproxen (Aleve) or acetaminophen (Tylenol) for headaches
  • Ondansetron (Zofran) or promethazine (Phenergan, Promethegan, Phenadoz) for nausea