High-Altitude Pulmonary Edema: How Travelers Are Treated and When Descent Is Urgent

The trekker’s cough started on the second night at the high camp. Dry at first, easy to blame on cold air. By morning the tent-mate noticed something different: the walk to the cook tent, maybe forty steps on level ground, left him bent over and gasping like he had sprinted uphill. He had felt fine yesterday. He had done nothing wrong.

That gap between “felt fine” and “cannot catch my breath sitting down” is the signature of high-altitude pulmonary edema, and it is why guides, expedition doctors and travel-medicine clinics talk about high altitude pulmonary edema treatment as a sequence with a clear first move rather than a menu of options. The lungs are filling with fluid because of the thin air itself, and the most reliable fix is thicker air.

This explainer walks through what is happening inside the chest, what rescuers and clinicians actually do, which parts of the plan are firmly evidence-based and which are still being studied, and the signs that turn a cautious wait into an urgent descent.

What is altitude sickness pulmonary edema, and how does HAPE differ from HACE?

Pulmonary edema is fluid where it should not be: inside the air sacs of the lungs, the tiny balloon-like alveoli where oxygen crosses into the blood. When the cause is the low oxygen of high elevation, doctors call it high-altitude pulmonary edema, or HAPE. It belongs to the family of altitude illnesses that also includes acute mountain sickness (AMS), the familiar headache-and-nausea picture, and high-altitude cerebral edema (HACE), in which the brain swells.

The three are related but not identical. The CDC’s Yellow Book, the reference used by travel clinics worldwide, describes altitude illness as a spectrum that becomes a concern above roughly 2,500 meters, with AMS affecting around a quarter of people who ascend quickly to that height. HAPE is far less common than AMS but far more dangerous, and it can develop with or without a preceding headache.

The distinction between HAPE and HACE matters at the trailside. HAPE is a lung problem: breathlessness that outpaces effort, a cough that may become wet, a sense of fluid in the chest. HACE is a brain problem: confusion, clumsiness, a stumbling walk, drowsiness that is hard to shake. Both can occur together, and both demand the same first response, which is descent. Where they diverge is in the medicines a clinician might consider, which is covered later in this article.

One more piece of vocabulary helps. Hypoxia means too little oxygen reaching the tissues. Hypoxemia means too little oxygen in the blood itself. HAPE produces both, and every element of its treatment, from walking downhill to a pressurized fabric bag, is a different route to the same goal of reversing them.

What actually happens in the lungs at high altitude?

Picture the lung’s blood vessels as a network of garden hoses wrapped around millions of tiny air sacs. At sea level, oxygen-rich air keeps those hoses relaxed and wide. At altitude, each breath carries less oxygen, and the lung responds with a reflex that is useful at sea level but backfires on a mountain: it constricts the small arteries. Normally this redirects blood away from a poorly ventilated patch of lung toward better ones. When the whole lung is short of oxygen, the whole network narrows at once.

Narrowing raises the pressure inside the pulmonary arteries. The Mayo Clinic’s overview of pulmonary edema explains that in high-altitude cases this pressure rise, combined with uneven constriction across the lung, forces fluid and even some blood cells out of the vessels and into the air sacs. Sections of lung that constrict less receive a flood of blood at high pressure, and their delicate vessel walls leak.

Fluid in the alveoli does two things. It blocks oxygen from crossing into the blood, so oxygen levels fall further. That deeper hypoxia tightens the arteries more, which raises pressure more, which pushes out more fluid. The loop feeds itself, and this is why HAPE tends to worsen at night, when breathing naturally slows during sleep and oxygen levels dip lowest.

Unlike the pulmonary edema seen in heart failure, the heart itself is usually working normally in HAPE. The problem sits entirely in the lung’s plumbing. That is also the good news: remove the trigger by restoring oxygen and the vessels relax, the leak slows, and the lung begins to reabsorb the fluid. Everything in high altitude pulmonary edema treatment is designed to break that loop as early as possible.

Who develops HAPE, and who is usually asked to wait before going higher?

HAPE does not pick the unfit. It is seen in marathon runners and in first-time trekkers, and physical conditioning offers no protection. According to the CDC Yellow Book, the strongest risk factors are how high a person goes, how fast they get there, how hard they exert themselves on arrival, and whether they have had HAPE before. A prior episode is a powerful predictor of another, because some people appear to have a lung circulation that constricts more vigorously in thin air.

Timing follows a pattern. The Yellow Book notes that HAPE typically develops within 2–4 days of arriving at a new altitude, most often the second night. It can also appear in people who have been high for weeks and then push to a new elevation, and in residents of high-altitude towns who return home after time at sea level.

Certain medical conditions raise concern. Pulmonary hypertension (chronically high pressure in the lung arteries), congenital heart abnormalities that alter blood flow through the lungs, and significant lung disease can all magnify the altitude response. The NHS advises anyone with a long-term heart or lung condition, or who is pregnant, to discuss altitude travel with a clinician beforehand. This is not a prohibition; it is a request to plan with someone who knows the individual’s history.

Who is usually asked to wait? Anyone with current symptoms of altitude illness, however mild, should not ascend further until those symptoms settle, a rule the NHS states plainly. Guides also ask people recovering from a chest infection to hold at their current elevation. Children are not more susceptible than adults, but they may struggle to describe what they feel, so caregivers watch behavior, appetite and breathing rate rather than asking for a symptom report.

What is the immediate treatment for pulmonary edema at altitude?

People searching for the immediate treatment for pulmonary edema often land on hospital pages describing heart failure, where the answer involves intravenous diuretics and cardiac medicines. On a mountain the answer is different, and simpler in one respect: the first treatment is to change the air.

The Cleveland Clinic’s guidance on altitude sickness puts it in one line: the most effective treatment for serious altitude illness is to go down. For HAPE specifically, the CDC Yellow Book lists three interventions that raise blood oxygen, in order of availability. Descent. Supplemental oxygen if a cylinder or concentrator is at hand. A portable hyperbaric chamber if descent must wait for daylight, weather or a rescue team.

Before any of these, the person should stop exerting themselves. Effort raises pulmonary artery pressure and speeds the leak, so a breathless trekker should not be carrying a pack, and where terrain allows, should be carried rather than walk. Keeping warm matters too, because cold increases the constriction of lung vessels. Sitting upright rather than lying flat often eases breathing, a simple positioning step that emergency clinicians use for any form of pulmonary edema.

What is not on the list is waiting for it to improve overnight. Because sleep lowers oxygen levels further, the night is when HAPE deteriorates. A person who is short of breath at rest in the evening should be moving downhill, breathing oxygen or in a pressure bag, not zipped into a sleeping bag hoping for morning.

Medicines have a role, discussed later, but the Yellow Book is explicit that they are adjuncts. They buy time and support the main effort. They do not replace the walk down or the oxygen cylinder, and none of them should delay either.

Why is descent the first-line high altitude pulmonary edema treatment?

Air pressure falls with elevation, and with it the amount of oxygen in each breath. At about 2,500 meters, the pressure of oxygen entering the lungs is roughly three quarters of its sea-level value; near 5,000 meters it is about half. Every hundred meters of descent adds oxygen back, and unlike a cylinder, the supply does not run out.

Descent works on HAPE at the level of the mechanism. Richer air relaxes the constricted lung arteries, pulmonary pressure falls, the leak of fluid into the air sacs slows and the lung’s own drainage begins to clear what has already accumulated. The Mayo Clinic notes that in high-altitude pulmonary edema, moving to a lower elevation is the key step and that symptoms often ease as elevation drops. This is why experienced guides talk about descent as a treatment rather than a retreat.

How far is enough? The CDC Yellow Book gives a working figure of roughly 1,000 meters of descent, or descending until symptoms clearly improve, whichever comes first. In practice the number is less important than the trend: a person who is breathing easier after 300 meters is being treated; a person who is no better after 1,000 meters needs oxygen and medical evaluation without further delay.

Descent also removes the variable that makes HAPE so treacherous, which is the night ahead. A tent at altitude is a place where oxygen will fall for eight hours. A lodge several hundred meters lower is a place where it will rise. Choosing the second option before dark is the single decision that most often changes the course of a HAPE episode, and it does not require any equipment or prescription.

The one caution is that a severely breathless person should not walk down unaided. Exertion worsens HAPE, so descent means being helped, carried or driven, with the patient doing as little work as the terrain allows.

When is descent urgent, and how far down is far enough?

Not every cough at altitude is HAPE, and not every case of mild AMS demands leaving the mountain. The NHS advice for mild altitude sickness is to stop ascending, rest at the current elevation and see whether symptoms settle over a day or two. HAPE changes that calculation, and three observations shift the plan from “wait and watch” to “go down now”.

The first is breathlessness at rest. Feeling winded on a steep slope is normal at altitude; feeling winded while sitting in a chair is not. The second is a decline in exercise tolerance that is out of proportion to companions, such as a strong walker who suddenly cannot keep up on flat ground. The third is a cough that changes character, becoming wet, producing frothy or pink-tinged sputum, or accompanied by a crackling sound in the chest. The CDC Yellow Book identifies these as the features that separate HAPE from ordinary altitude fatigue.

Once any of these appears, the Yellow Book’s guidance is descent of about 1,000 meters or to the last elevation at which the person felt well. If a portable oxygen saturation monitor is available, a reading that is markedly lower than that of healthy companions at the same altitude supports the decision, though a monitor should never overrule what is visible: a person struggling to breathe is the finding that matters.

Urgency rises further if confusion, unsteadiness or unusual drowsiness appear alongside breathing trouble, because that combination suggests HACE is developing too. The Cleveland Clinic describes both conditions as medical emergencies. At that point every hour of delay carries risk, night descent with headlamps and helpers is justified, and evacuation by vehicle or helicopter should be requested wherever it exists.

How far is far enough is answered by the patient, not the map: low enough that breathing at rest is comfortable, and then no re-ascent until a clinician has assessed them.

How do oxygen and portable hyperbaric chambers work?

Supplemental oxygen does chemically what descent does geographically. Breathing from a cylinder or concentrator raises the concentration of oxygen in each breath, which relaxes the lung arteries and lowers pressure even if the surrounding air stays thin. The CDC Yellow Book lists oxygen as a treatment that can substitute for descent when getting down is impossible, and as a companion to descent when both are available. Many high-altitude lodges, trekking agencies and mountain rescue posts keep it for exactly this purpose.

A portable hyperbaric chamber is a different route to the same destination. It is a sealed fabric bag, large enough for one person to lie inside, inflated with a foot pump until the pressure within is higher than the air outside. Higher pressure means more oxygen in every breath, so the person inside is effectively breathing the air of a lower altitude. The Yellow Book describes the effect as equivalent to a descent of well over 1,000 meters, achieved without moving.

The bag has limits worth understanding. Someone must keep pumping to maintain pressure and flush out exhaled carbon dioxide, so it demands attention from companions for as long as it is in use. Patients who are confused, vomiting or claustrophobic may not tolerate it. And when the bag is opened, the person returns to the real altitude, so improvement inside does not mean the episode is over. Expedition doctors treat the chamber as a bridge that stabilizes a patient overnight or during a storm until true descent becomes possible.

Neither oxygen nor the bag is a reason to stay high. Both are tools for a situation where the ground itself is the obstacle. When the trail down opens, the guidance is to take it.

Which medicines are used in high altitude pulmonary edema treatment, and what do they do?

Medicines enter the HAPE picture as supporting players, and the CDC Yellow Book is careful to frame them that way: useful when descent or oxygen are delayed or unavailable, never a substitute for either. Because HAPE is fundamentally a pressure problem in the lung’s arteries, the medicines studied for it are those that relax those vessels.

The best established is a calcium channel blocker, a class of medicine that widens blood vessels by relaxing the muscle in their walls. Nifedipine is the generic most often described in guidelines for this purpose. By lowering pulmonary artery pressure it can reduce the force driving fluid into the air sacs. Guidelines also describe it for prevention in people with a history of HAPE who are planning a return to altitude, a decision made with a clinician before travel.

Phosphodiesterase-5 inhibitors, a class that includes sildenafil and tadalafil, also relax lung vessels through a different chemical pathway. The Yellow Book lists them as alternatives when a calcium channel blocker is not suitable. Evidence for both classes in treating established HAPE is thinner than for descent and oxygen, resting largely on small studies and physiological reasoning rather than large trials.

Two medicines commonly carried by trekkers deserve clarification. Acetazolamide, which speeds acclimatization by changing the blood’s acid balance, is used for AMS prevention and treatment, not for HAPE. Dexamethasone, a corticosteroid that reduces swelling, is the medicine of choice for HACE and may be considered when HAPE and HACE coexist, but it does not treat the lung leak itself.

Whether any of these is appropriate, in what form and for how long, is a question for the prescribing clinician, ideally before the trip when a travel-medicine consultation can weigh the person’s history and itinerary.

HAPE treatment options compared: what each one does and where it fits

Seeing the tools side by side clarifies why guidelines rank them as they do. Each raises oxygen in the blood or lowers pressure in the lung arteries; they differ in speed, availability and how long the benefit lasts. The table draws on the CDC Yellow Book and the NHS altitude sickness guidance.

Intervention	How it helps	Typical role	Main limitation
Descent (about 1,000 m or until symptoms ease)	Permanently increases oxygen in each breath; relaxes lung arteries	First-line for any HAPE	Terrain, darkness and weather; exertion must be minimized
Supplemental oxygen	Raises inhaled oxygen concentration directly	Alongside descent, or in place of it when descent is impossible	Finite supply; equipment not always present
Portable hyperbaric chamber	Increases air pressure, simulating a lower altitude	Bridge when descent is delayed	Needs continuous pumping; effect ends when opened
Calcium channel blocker	Relaxes pulmonary arteries, lowering pressure	Adjunct when oxygen or descent delayed; prevention in prior HAPE	Weaker evidence than descent; prescription decision
PDE-5 inhibitor	Relaxes pulmonary arteries via a different pathway	Alternative adjunct	Limited trial evidence; prescription decision
Rest, warmth, upright position	Reduces exertion-driven pressure rise and eases breathing	Always, from the first minute	Supportive only; does not reverse the leak alone

Two patterns stand out. The interventions with the strongest evidence are also the least technological: going down and breathing oxygen. And every item in the lower rows exists to serve the upper ones, either by holding a patient steady until descent is possible or by reducing the chance of a repeat episode on a future trip. Anyone comparing these options for their own situation should do so with a clinician who knows their medical history, because the right combination depends on the person, the route and the rescue options available.

Can HAPE go away on its own?

The honest answer has two parts. HAPE can resolve without any medicine, because the underlying process reverses once oxygen is restored. The lung’s constricted vessels relax, pressure falls and the fluid is reabsorbed over a few days. In that sense the body does the repair work itself. What HAPE does not reliably do is resolve while a person stays at the altitude that caused it and continues to sleep, exert and breathe thin air.

The distinction matters because the phrase “goes away on its own” is sometimes used to justify waiting a night to see. The CDC Yellow Book describes HAPE as the leading cause of death from altitude illness and states that it can progress rapidly, particularly overnight. Untreated, the loop described earlier tends to tighten: less oxygen, more constriction, more fluid. Mild cases caught early at modest altitude sometimes improve with rest alone, but no one can tell in advance which case that will be.

Historical reports from the era before descent and oxygen were understood as treatment describe high fatality rates. Because those figures come from very different circumstances, this article does not quote them, and modern guidelines do not offer a single survival percentage for treated HAPE. What they do say, consistently, is that when descent, oxygen or pressurization begin promptly, most people improve within hours and recover fully within days.

So the practical reframe is this. HAPE improves on its own once you change the air; it does not improve on its own if you do not. The body will do the healing, but only after the trigger has been removed. A trekker asking whether they can wait is really asking whether they can predict the night ahead, and the evidence says they cannot.

How long does it take to recover from high altitude pulmonary edema?

Recovery from HAPE tends to run faster than people expect once treatment starts, which is one of the reassuring features of a frightening condition. The CDC Yellow Book describes symptoms improving within hours of adequate descent or oxygen, with the cough and breathlessness typically clearing over the following 2–3 days as the lung reabsorbs fluid. The Mayo Clinic notes that people with pulmonary edema from altitude usually recover once they reach lower elevation, though anyone with significant symptoms should be evaluated by a clinician.

The first day is about oxygen. Whether in a lower lodge, a clinic or a hospital, the aim is to keep blood oxygen at a healthy level, which may mean supplemental oxygen for a period even after descent. A chest X-ray, if performed, often shows patchy fluid that lags behind how the person feels; that is expected and does not by itself mean treatment is failing.

Days two through seven are about rest and gradual movement. Fatigue after HAPE is common and does not signal lasting harm. A lingering dry cough can persist for a week or two after the fluid has cleared. People are usually advised to avoid strenuous exertion until they can climb stairs at low altitude without unusual breathlessness.

Returning to altitude is the question that follows. The Yellow Book allows cautious re-ascent once symptoms have fully resolved, typically after several days at lower elevation, with a slower schedule and, for some, preventive medicine discussed with a clinician. A single episode does not end a person’s mountain travel, but it does change how future trips are planned.

Follow-up matters after any HAPE episode that needed medical care. A clinician may want to check for pulmonary hypertension or a heart abnormality that could have contributed, particularly if the episode occurred at a relatively modest altitude or with a slow ascent.

What people often get wrong about HAPE

The first misconception is that fitness protects you. It does not. The CDC Yellow Book is unambiguous that physical conditioning has no bearing on susceptibility, and the fittest members of a group are sometimes at higher risk because they ascend faster and exert harder on arrival. HAPE responds to how the lung circulation reacts to thin air, which training does not alter.

The second is that HAPE always follows AMS. Many cases arrive without the classic headache, which is why the earlier section emphasized breathlessness at rest and declining exercise tolerance as the signals to watch. Waiting for a headache before considering the lungs can waste a critical night.

The third is that a cough at altitude is just dry air. Dry air does cause a cough, and most high-altitude coughs are harmless. The difference is trajectory and company: a cough that arrives with breathlessness out of proportion to effort, that becomes wet or produces frothy sputum, or that keeps a person from lying down, is not a humidity problem.

The fourth is that medicines carried for AMS will handle HAPE. Acetazolamide speeds acclimatization; it is not a treatment for fluid in the lungs. Reaching for it and staying put can feel like taking action while the actual treatment, descent, is postponed.

The fifth is that having oxygen means you can stay. The NHS and CDC both frame oxygen as a companion to descent or a bridge until it is possible, not as permission to continue the itinerary. A cylinder empties; the mountain does not get lower.

The last is that one episode means the end of mountain travel. It means slower ascents, a conversation with a travel-medicine clinician, and greater vigilance on night two. Many people return to altitude after HAPE with a changed plan and no repeat.

Questions to ask your care team before and after altitude travel

A travel-medicine consultation before a high-altitude trip is where most HAPE prevention actually happens, and the value depends on the questions brought to it. The same is true of the follow-up visit after an episode. These prompts are drawn from the areas the CDC Yellow Book and NHS guidance identify as most consequential.

Before travel, ask how your itinerary compares with the ascent rates the NHS describes as lower risk: taking 2–3 days to acclimatize before going above 2,500 meters, limiting the daily gain in sleeping altitude to roughly 300–500 meters once above 3,000 meters, and building in a rest day every 600–900 meters. Ask whether flying directly to a high-altitude city, rather than approaching by road, changes your risk. Ask what your existing conditions or medicines mean at altitude, especially anything affecting the heart, lungs or blood pressure.

Ask whether preventive medicine is worth discussing given your history, and if so, what its purpose is and what it does not protect against. Ask what signs should prompt descent regardless of the schedule, and how you would arrange evacuation on the specific route. Ask whether carrying a pulse oximeter is useful for your group and how to interpret readings alongside how people look.

After an episode, ask whether tests for pulmonary hypertension or a structural heart difference are warranted. Ask how long to wait before returning to altitude and how the next ascent should differ. Ask what symptoms in the coming weeks would need a review. And ask for a written summary you can carry on future trips, so that a clinician in a remote clinic knows your history within a minute of reading it.

None of these questions has a universal answer. Their purpose is to make sure the decisions that shape your trip are made with your clinician, deliberately, rather than by default on the trail.

When to call your doctor

Altitude illness is one of the few conditions where the first call is often not to a doctor but to the person next to you, because the first treatment is a change of place. That said, medical help should be sought, by whatever means the location allows, in every case of suspected HAPE. The Cleveland Clinic classifies both HAPE and HACE as emergencies, and a clinician’s involvement early makes the difference between a managed descent and a rescue.

Seek care urgently, and begin descent while doing so, if a person at altitude is breathless at rest or cannot lie flat because of breathing difficulty; if a cough becomes wet, frothy or pink-tinged; if lips or fingertips look bluish or gray; if a previously strong walker cannot keep pace on level ground; if breathing is rapid and shallow even after several minutes of rest; or if any of these occurs alongside confusion, unsteady walking, unusual drowsiness or a headache that does not ease with rest. The combination of breathing trouble and altered thinking is the most dangerous pattern, because it suggests both lungs and brain are affected.

After descent, a clinician should assess anyone who required oxygen or a pressure chamber, whose symptoms have not clearly improved within hours of reaching lower altitude, or who has a history of heart or lung disease. Call your doctor in the days that follow if breathlessness returns at low altitude, if a fever develops, if the cough produces discolored or bloody sputum, or if chest pain appears, since these can point to an infection or another problem that needs its own evaluation.

Once home, book a follow-up even if you feel well. The treating team decides whether further tests are needed and how future travel should be planned. What no article can do is examine you, and every decision about medicines, timing and return to altitude belongs with the clinicians who can.

Frequently asked questions

Can HAPE go away on its own?

HAPE can resolve without medicine once the person reaches richer air, because the lung vessels relax and the fluid is reabsorbed. It does not reliably improve if the person stays at the altitude that caused it, and the CDC Yellow Book warns it can worsen quickly overnight. The body does the healing, but only after descent, oxygen or pressurization removes the trigger.

What is the immediate treatment for pulmonary edema at altitude?

Stop exertion, keep the person warm and upright, and begin descent while arranging supplemental oxygen or a portable hyperbaric chamber if descent is delayed. These three measures all raise blood oxygen, which is the core of high altitude pulmonary edema treatment. Medicines that relax lung vessels may be added by a clinician, but they support descent and oxygen rather than replace them.

How long does it take to recover from high altitude pulmonary edema?

Symptoms typically ease within hours of adequate descent or oxygen, and the CDC Yellow Book describes clearing of breathlessness and cough over about 2–3 days. Fatigue and a dry cough can linger for a week or two. Return to altitude is usually possible once symptoms have fully resolved, with a slower ascent plan agreed with a clinician.

What is the survival rate for HAPE?

Current guidelines do not quote a single survival percentage for treated HAPE, and older figures come from a period before descent and oxygen were understood as treatment, so they are not a fair guide. What guidelines state consistently is that HAPE is the leading cause of altitude-related death when untreated, and that most people recover fully when descent or oxygen begins promptly.

How do you treat HAPE in the field without a doctor?

The field plan is descent, oxygen and pressurization, in whatever order availability allows. Help the person down about 1,000 meters or until they breathe comfortably at rest, using a vehicle or carry rather than having them walk under load. Use oxygen or a portable hyperbaric bag if descent must wait. Request evacuation early, and seek medical assessment after descent.

What is the difference between HAPE vs HACE?

HAPE is fluid in the lungs, causing breathlessness at rest and a cough that may turn wet; HACE is swelling of the brain, causing confusion, unsteadiness and drowsiness. Both are emergencies, both are treated first with descent and oxygen, and they can occur together. The medicines a clinician might consider differ: vessel-relaxing drugs for HAPE, a corticosteroid for HACE.

Is HAPE the same as altitude sickness pulmonary edema?

Yes. High-altitude pulmonary edema, HAPE and altitude sickness pulmonary edema all describe the same condition: fluid leaking into the lung’s air sacs because low oxygen has raised pressure in the lung arteries. It is the most serious lung complication of altitude illness and is distinct from the pulmonary edema caused by heart failure, in which the heart itself is the problem.

What is a typical HAPE recovery time before flying home?

Guidelines do not set a fixed waiting period. Most people can travel once breathing at rest and mild activity is comfortable at low altitude, usually within days. Aircraft cabins are pressurized to a moderate altitude, so anyone who needed oxygen should ask the treating clinician about timing and whether in-flight oxygen is advisable. Moving regularly and staying hydrated during travel are sensible for everyone.

Does taking acetazolamide prevent HAPE?

Acetazolamide speeds acclimatization and is used for preventing and treating acute mountain sickness; it is not established as a treatment for HAPE. Guidelines describe different medicine classes, such as calcium channel blockers, for people with a history of HAPE who plan to return to altitude. Whether any preventive medicine suits an individual is a decision for the prescribing clinician before travel.

Can I go back to high altitude after having HAPE?

Many people do. The CDC Yellow Book allows cautious re-ascent once symptoms have fully resolved, with a slower schedule than before. A prior episode is the strongest predictor of a repeat, so a travel-medicine consultation is advisable to review ascent rates, possible preventive medicine and evacuation options. Some clinicians also check for pulmonary hypertension or heart differences after an episode.

References

• NHS: Altitude sickness
• Cleveland Clinic: Altitude Sickness
• MedlinePlus: Acute mountain sickness

This article is for general information only and is not a substitute for professional medical advice. Please consult a qualified doctor about your individual situation.