High altitude pulmonary edema (HAPE) is a serious lung condition that may develop when you’re at high altitudes.

Pulmonary edema is when fluid builds up in your lungs. In the case of HAPE, lower oxygen intake at high altitudes causes your blood vessels to narrow, leading to this fluid buildup.

HAPE is one of three types of altitude sickness. The other two are acute mountain sickness (AMS), the most common form, and high altitude cerebral edema (HACE).

With AMS, symptoms such as nausea, fatigue, and headache resolve within 12 to 48 hours after your body acclimates to the higher altitude. With HAPE, symptoms start up to 5 days after you’ve reached a high altitude, and it can take 2 to 3 days to completely recover.

When venturing to a high altitude for recreational purposes, such as skiing, mountain climbing, or hiking, it’s important to understand the potential health risks.

Here’s what you need to know about HAPE, including which symptoms to look for and when you should seek medical help.

HAPE develops due to exposure to low oxygen levels at high altitudes. Environmental factors, such as cold air, can worsen your symptoms by causing increased stress on your lungs.

Your risk for altitude illness may be greatest above 8,000 feet (about 2,500 meters). The risk is especially high if you ascend too quickly and don’t allow time for your body to acclimate slowly.

While it’s rare to experience HAPE at altitudes lower than this, it’s still possible, especially if you have a history of HAPE.

Other risk factors include:

  • using sleep medication
  • consuming too much salt
  • having underlying health conditions that affect blood flow to your lungs

Also, while AMS is more common in adults over the age of 50, HAPE occurs more often in children and young adults, regardless of fitness level.

While the link between age and HAPE isn’t clear, it may be due to the types of activities involved.


Both HAPE and HACE are types of altitude illnesses.

HACE is a rare progression of AMS. HAPE may occur with or without symptoms of AMS, such as headache, fatigue, and lethargy.

But unlike HACE, HAPE causes distinct breathing difficulties, including breathlessness while you’re resting. HAPE is also more rapidly fatal than HACE, though both conditions can be deadly.

HAPE affects the lungs, while HACE impacts your brain. Thus, HACE may also cause certain symptoms not seen in HAPE, such as hallucinations, loss of coordination, and confusion.

Up to 14% of people with HAPE also have HACE at the same time.

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Some describe the symptoms of AMS as similar to an alcohol-related hangover. But a key sign of HAPE is breathlessness.

At first, you may notice breathing difficulties during exertion, such as walking and hiking. As symptoms worsen, you may start to feel breathless even when you’re at rest.

Symptoms of HAPE typically appear within a few days of your ascent.

Additional symptoms of HAPE may include:

  • general weakness
  • a persistent cough
  • coughing up white or pink sputum (a frothy liquid)
  • chest tightness
  • a bluish tinge to your lips or skin

When to seek help

HAPE requires immediate action and medical attention. If you experience symptoms, start to descend immediately, with the help of others if available.

Medical facilities may not be immediately available. Still, call first responders such as paramedics or ski patrol. They can help you move and provide emergency care.

Go immediately to the nearest hospital that is able to provide oxygen therapy and has professionals able to care for HAPE. Even if your symptoms start to improve, you should still seek medical help as soon as possible.

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If you suspect HAPE, you must descend immediately. Ideally, it would be best if you did this with the help of others, such as medical staff. Increased exertion could worsen your symptoms.

Another treatment option is supplemental oxygen, particularly if you have access to a medical facility at a high altitude nearby. Portable oxygen may also be necessary if you can’t make an immediate descent.

A doctor may also prescribe nifedipine, an anti-hypertensive medication. Nifedipine may treat HAPE by alleviating chest tightness and increasing your ability to breathe better.

The doctor may prescribe this oral medication in either 30 mg doses every 12 hours (extended-release) or 20 mg doses every 8 hours.

Once you have safely descended, you’ll need to seek further treatment for HAPE at the nearest hospital.

The key to preventing HAPE is acclimation. It’s best to give your body a chance to get used to the new altitude.

You may be tempted to get to your destination quickly. But gradual ascensions are the surest way to prevent altitude illnesses like HAPE. Research has shown that if you take only 1 or 2 days to ascend to 4,500 meters (about 14,750 feet), you’re 30 times more likely to develop HAPE than if you take 4 days.

The Centers for Disease Control and Prevention (CDC) suggest the following tips to ascend slowly and safely:

  • Avoid going above 9,000 feet (2,750 meters) in 1 day. Your sleeping elevation on the first day should be lower than this level.
  • Once you’re above 9,000 feet, ascend no more than 1,600 feet (500 meters) per day.
  • Over 9,000 feet, have a rest day for every additional 3,300 feet (1,000 meters).
  • Consider a rest day every 3 to 4 days for longer trips.

Experts also recommend having a previous high-altitude experience within 30 days of your trip.

You should also avoid alcohol or heavy exertion within the first 2 days of your journey.

You may consider talking with a doctor about taking preventive medications. Options include:

Keep in mind that these medications may cause mild side effects, such as low blood pressure, dizziness, and headache.

Any of the following symptoms should be considered possible HAPE. A clinician would consider two or more of these symptoms as definitive for HAPE if there’s no other explanation:

  • chest tightness or pain
  • cough
  • shortness of breath while resting
  • decreased exercise tolerance

To confirm a possible diagnosis of HAPE, a clinician would look for two or more of the following:

  • bluish or grayish skin or lips
  • crackling or wheezing in your lungs
  • rapid heart rate
  • rapid breathing

Some symptoms may mimic those of other lung issues, such as pneumonia or pulmonary embolism. A doctor may need to order or perform tests to rule out other conditions.

A chest X-ray, if available, may help confirm HAPE. A doctor may also order an ultrasound to look for pulmonary edema and an ECG and echocardiogram to look for other potential causes of pulmonary edema besides HAPE.

Medical facilities are not always available at high altitudes. Based on your symptoms, you may need to make a decision before getting a clinical diagnosis.

If you experience decreased exercise tolerance and have trouble breathing, you should descend immediately.

At what elevation should I start being concerned about high altitude pulmonary edema?

According to the CDC, altitude illness may develop at altitudes above 8,000 feet (2,500 meters). An even higher incidence of HAPE is noted in skiers and climbers who ascended above 14,000 feet (4,250 meters).

But it’s possible to experience HAPE at lower elevations than these. If you don’t allow for proper acclimatization before your activity or have a history of HAPE, you have a higher risk of developing altitude illness.

How long do symptoms of high altitude pulmonary edema last?

Symptoms of HAPE should resolve once you make an immediate descent or access other treatments, such as supplemental oxygen. But you may not achieve full clinical recovery for another several days.

Even if you’re feeling better after recovering from symptoms of HAPE, you should seek evaluation at a hospital right after your descent.

Are there long-term effects of high altitude pulmonary edema?

While recovery from HAPE is possible, prolonged exposure to high altitudes may cause permanent changes in your pulmonary vessels. This may cause long-term pulmonary hypertension.

If you enjoy activities like skiing or climbing, you should know that the likelihood of HAPE reoccurring is very high. The recurrence rate is about 60%.

Can I get high altitude pulmonary edema when flying?

HAPE is most common among hikers, climbers, and skiers. While planes fly at very high altitudes, air cabins on commercial flights are usually pressurized. This means that your body doesn’t experience the effects of high altitude that cause HAPE.

While you’re not likely to develop HAPE while flying, airplane travel may worsen symptoms of preexisting pulmonary hypertension.

Is high altitude pulmonary edema fatal?

Yes, HAPE can be fatal. HAPE has a 50% fatality rate in those who don’t immediately descend high altitudes or don’t seek treatments.

Time is of the essence, as death can occur in hours to days.

HAPE is a serious lung condition that develops due to a lack of oxygen when moving to extremely high altitudes.

Some people may be at greater risk due to underlying health conditions. Still, it’s important for all to be aware of the symptoms of HAPE, regardless of age or fitness level.

You must seek treatment for suspected HAPE immediately to prevent death.

Aside from knowing the symptoms of HAPE, it helps to plan ahead. Given the severity and frequency of HAPE, even in young and previously healthy people, any high-altitude expeditions should include the following in their plan:

  • Make time in your schedule to gradually acclimate to higher elevations during your trip and designate regular rest days.
  • Know how and where to descend in case of the onset of symptoms.
  • Know where to access medical care as quickly as possible.

You may also consider talking with a doctor about medications that may help prevent HAPE during your ascent.