n

두통, 메스꺼움, 어지러움, 피로… 이 증상은 고산병일 수 있습니다

nnnn

1. 불편함의 원인을 알고 계신가요?

nnnn

최근 원인 모를 불편함을 느끼고 계신가요?

nnnn

머리가 무겁거나 욱신거리는 통증이 있을 수 있습니다. 속이 메스껍고 식욕이 없을 수도 있습니다. 일어설 때 어지러움을 느끼거나, 걸을 때 발이 불안정할 수 있습니다. 몸이 나른하고 평소보다 쉽게 피로해집니다. 밤에는 잠들기 어렵거나, 밤중에 반복적으로 깨어납니다.

nnnn

이러한 증상이 익숙하게 느껴진다면, 잠시 되돌아보십시오. 지난 며칠이나 몇 주 동안 어딘가를 여행하셨나요? 산에 오르거나, 고원 지역을 방문하거나, 장거리 비행을 하셨나요?

nnnnnn

nnnn

If something comes to mind, the discomfort you’re experiencing might be altitude sickness.

nnnn

When people hear “altitude sickness,” many assume it’s a special condition that only affects serious mountaineers and alpinists—something that happens to people attempting Everest or Kilimanjaro, not something relevant to them.

nnnn

However, altitude sickness is actually much closer to our daily lives than most people realize. Those who have climbed Mount Fuji, visited highland tourist spots like Tateyama or Norikura, traveled to South America or Tibet, or enjoyed skiing in Switzerland or Colorado—many of these travelers have experienced altitude sickness without even knowing it.

nnnn

What might surprise you even more is that you can’t assume you’re safe just because you didn’t climb a mountain on foot. When you travel quickly to high elevations by car or ropeway, you can still develop altitude sickness even without climbing yourself. Additionally, airplane cabins are pressurized to levels lower than ground level, so some people experience altitude sickness-like symptoms during or after long flights.

nnnn

In this article, we’ll explain in detail what altitude sickness is, what situations can trigger it, and how to prevent it. We’ll also cover what to do if you do develop altitude sickness, and discuss other conditions that can cause similar symptoms.

nnnn

Whether you’re currently experiencing unexplained symptoms or planning a trip to high altitude destinations, please read through to the end.

nnnn

2. Altitude Sickness Is More Common Than You Think

nnnn

Before diving into the details of altitude sickness, let’s first understand just how common this condition really is.

nnnn

Medically speaking, altitude sickness is defined as “a syndrome associated with hypoxia that occurs at high altitude.” Simply put, at higher elevations where the air contains less oxygen, the body cannot adapt to the environment and various symptoms appear.

nnnn

Generally, the risk of developing altitude sickness increases at elevations above 2,500 meters (approximately 8,200 feet). However, some people may experience symptoms at elevations as low as 2,000 meters (6,500 feet). The important thing to understand is that altitude sickness is not a condition that only affects people with certain physical constitutions. It can happen to anyone, regardless of age, gender, fitness level, or athletic experience.

nnnn

In fact, studies suggest that 30% to 50% of people who climb Mount Fuji experience some form of altitude sickness symptoms. Mount Fuji is one of Japan’s most popular climbing destinations, with people from Japan and around the world attempting to reach its summit every summer. A significant portion of these climbers suffer from headaches, nausea, and other symptoms.

nnnn

So, in what specific situations might you develop altitude sickness? Let’s look at some typical scenarios.

nnnn

Climbing Mount Fuji

nnnn

Mount Fuji stands at 3,776 meters (12,388 feet), making it Japan’s highest mountain. Most climbers begin their ascent from the 5th Station (approximately 2,300-2,400 meters / 7,500-7,900 feet), but as they approach the summit, atmospheric pressure drops and oxygen levels decrease. The risk of altitude sickness is particularly high for those attempting “bullet climbing”—starting at night and climbing straight through to reach the summit for sunrise—as the body has no time to acclimatize to the altitude.

nnnn

Highland Tourism Accessible by Car or Bus

nnnn

Japan has many highland areas easily accessible by car, bus, or ropeway, including Mount Tateyama (approximately 3,000 meters / 9,800 feet), Mount Norikura (approximately 2,700 meters / 8,900 feet), and Kamikochi (approximately 1,500 meters / 4,900 feet). Because visitors don’t climb these places on foot, they may not be aware of the altitude sickness risk. However, rapidly ascending to high elevations in a short time can actually place greater stress on the body.

nnnn

Long-Haul Flights

nnnn

Aircraft cabins at cruising altitude are pressurized to approximately 0.8 atmospheres, equivalent to an elevation of roughly 1,800-2,400 meters (5,900-7,900 feet). As a result, some people experience headaches and fatigue during or after long flights. While this isn’t technically “altitude sickness” in the strict sense, similar mechanisms related to low pressure and reduced oxygen can trigger these symptoms. Those with pre-existing respiratory or cardiovascular conditions should be particularly cautious.

nnnn

High-Altitude Travel Abroad

nnnn

Many popular tourist destinations and cities around the world are located above 3,000 meters (9,800 feet). Cusco, Peru (approximately 3,400 meters / 11,200 feet), the gateway to Machu Picchu; La Paz, Bolivia (approximately 3,600 meters / 11,800 feet); and Lhasa, Tibet (approximately 3,650 meters / 12,000 feet) are all popular destinations where travelers are exposed to altitude sickness risk from the moment they arrive. Flying from Japan and stepping off the plane at an airport already above 3,000 meters places significant stress on the body.

nnnn

Skiing and Tourism at High-Altitude Resorts

nnnn

High-altitude ski resorts in places like Zermatt, Switzerland and Colorado, USA also pose altitude sickness risks. When focused on enjoying skiing or snowboarding, people often attribute their physical discomfort to tiredness or cold weather, overlooking the possibility of altitude sickness.

nnnn

As you can see, altitude sickness is not just a concern for mountaineers. In today’s world where people travel to high elevations for tourism, leisure, and business, having accurate knowledge about altitude sickness is extremely important.

nnnn

3. What Is Altitude Sickness?

nnnn

Let’s take a closer look at what altitude sickness actually is.

nnnn

At sea level where most of us live, the air contains approximately 21% oxygen. This oxygen concentration doesn’t change at higher elevations, but as atmospheric pressure decreases, the number of oxygen molecules in the same volume of air decreases. This means that with each breath at high altitude, the body takes in less oxygen.

nnnn

For example, at the summit of Mount Fuji (3,776 meters / 12,388 feet), atmospheric pressure drops to approximately 63% of sea level. This means that even breathing normally, you can only take in about two-thirds of the oxygen you would at sea level.

nnnn

Our bodies attempt to adapt to these low-oxygen environments in various ways. We try to breathe deeper and faster to increase oxygen intake, and our heart rate increases to deliver oxygen more efficiently throughout the body. Given time, the body can even produce more red blood cells to enhance oxygen-carrying capacity.

nnnn

However, these adaptations take time. When we ascend too rapidly, the body cannot adapt quickly enough, and various symptoms appear. This is altitude sickness.

nnnn

Altitude sickness can be broadly categorized into three types:

nnnn

Acute Mountain Sickness (AMS)

nnnn

This is the most common form of altitude sickness. The primary symptom is headache, often accompanied by nausea, dizziness, fatigue, and sleep disturbances. Symptoms typically begin 6-12 hours after arriving at high altitude. Mild cases often improve naturally with rest, but continuing activity while ignoring symptoms can lead to worsening conditions.

nnnn

High Altitude Pulmonary Edema (HAPE)

nnnn

This condition can occur when acute mountain sickness progresses or when altitude sickness presents severely from the onset. Fluid accumulates in the lungs, making breathing difficult. Characteristic symptoms include shortness of breath even at rest, coughing, and producing pink, frothy sputum. This is a life-threatening emergency requiring immediate descent and medical attention.

nnnn

High Altitude Cerebral Edema (HACE)

nnnn

This extremely dangerous condition involves swelling of the brain. Symptoms include severe headache, inability to walk straight (ataxia), confusion, and altered consciousness. This is also a life-threatening emergency requiring immediate descent and medical treatment.

nnnn

A crucial point to understand about altitude sickness is that overconfidence—thinking “I’ll be fine”—is the most dangerous attitude. Even physically fit people and regular exercisers can develop altitude sickness. In fact, fit individuals may push themselves too hard precisely because of their fitness, worsening their condition. Even someone who had no problems at high altitude in the past may develop altitude sickness depending on their current health and condition. Susceptibility to altitude sickness varies between individuals and even within the same person at different times.

nnnn

4. Understanding the Symptoms of Altitude Sickness in Detail

nnnn

Let’s examine altitude sickness symptoms more closely. Understanding the characteristics of these symptoms will help you recognize early signs of trouble in yourself or your companions.

nnnn

4-1. Mild to Moderate Symptoms (Acute Mountain Sickness)

nnnn

Headache

nnnn

Headache is the most common symptom of altitude sickness. Some statistics suggest that 80-90% or more of people who develop altitude sickness experience headaches.

nnnn

Altitude sickness headaches can vary in character—some feel like throbbing, pulsating pain, while others feel like heavy pressure squeezing the entire head. The intensity can range from mild discomfort to severe pain that interferes with daily activities.

nnnn

Characteristically, these headaches begin several hours after arriving at high altitude and tend to worsen at night and in the early morning. This is thought to be because breathing becomes shallower during sleep, leading to increased oxygen deprivation.

nnnn

Nausea and Loss of Appetite

nnnn

Gastrointestinal problems are also common with altitude sickness. Symptoms include general queasiness, loss of appetite, and actual vomiting.

nnnn

These symptoms are thought to result from autonomic nervous system imbalances caused by low oxygen levels, as well as stimulation of the brain’s vomiting center. While you may not feel like eating, going without food can lead to decreased physical strength and worsening symptoms, so it’s important to consume small amounts of fluids and nutrients.

nnnn

Dizziness and Unsteadiness

nnnn

Feeling lightheaded when standing up, unsteady when walking, and foggy-headed are also characteristic symptoms of altitude sickness.

nnnn

These symptoms signal that the brain is not receiving adequate oxygen. They tend to be stronger when standing up suddenly or after climbing stairs. Severe unsteadiness carries a risk of falls and injuries, so it’s important to stay still and rest rather than moving around unnecessarily.

nnnn

Fatigue and Extreme Tiredness

nnnn

At high altitude, even normal activities can make the body extremely tired. Symptoms include becoming breathless after walking just a short distance, feeling like the body is heavy and difficult to move, and experiencing overwhelming fatigue even without doing anything.

nnnn

This occurs because the body is working hard in an oxygen-depleted environment. The heart works harder to pump more blood, and the lungs work harder 더 많은 산소를 섭취하기 위해. As a result, the body consumes more energy than usual, leading to increased fatigue.

nnnn

Sleep Disturbances

nnnn

Sleep quality often deteriorates significantly at high altitude. Many people experience difficulty falling asleep, waking multiple times during the night, waking due to breathlessness, or waking in the morning still feeling tired.

nnnn

A particularly characteristic phenomenon is “periodic breathing,” which involves alternating between deep breaths and shallow breaths (or brief breathing pauses). This changing breathing pattern can cause the brain to awaken, disrupting sleep. The person may feel like they woke up because they couldn’t breathe, or they may not know why they woke up.

nnnn

4-2. Warning Signs of Severe Illness (Dangerous Symptoms Not to Ignore)

nnnn

If the following symptoms appear, altitude sickness may be progressing to a severe stage requiring emergency action.

nnnn

Severe Headache

nnnn

A headache that doesn’t respond to pain medication at all, or one that temporarily improves only to return severely, is a dangerous sign. Be particularly concerned if the pain feels unlike anything you’ve experienced before.

nnnn

Repeated Vomiting

nnnn

Vomiting not just once but repeatedly can lead to dehydration and electrolyte imbalances, causing rapid deterioration.

nnnn

Shortness of Breath at 휴식

nnnn

While breathlessness during climbing or exercise is normal, persistent difficulty breathing while sitting or lying down may indicate high altitude pulmonary edema. Rapid, shallow breathing or inability to get relief from deep breaths are particular warning signs.

nnnn

Coughing with Pink Sputum

nnnn

Persistent dry coughing, or coughing that produces pink or blood-tinged frothy sputum, may indicate fluid accumulation in the lungs. This is a typical symptom of high altitude pulmonary edema and constitutes a life-threatening emergency.

nnnn

Ataxia (Inability to Walk Straight)

nnnn

Inability to walk straight on flat ground, needing to hold onto something to stand, or awkward hand and foot movements suggest possible high altitude cerebral edema. This is sometimes described as walking “like a drunk person.”

nnnn

Altered Consciousness

nnnn

Seeming dazed, slow to respond to questions, disorientation (not knowing what time it is or where you are), and confused speech are also warning signs of high altitude cerebral edema. The affected person often isn’t aware of these changes, so companions must watch for them.

nnnn

If even one of these severe warning signs appears, immediately begin descending to lower elevation. If you’re climbing toward a summit, stop and begin descending. If you’re at a high-altitude lodge, try to move to a lower elevation lodge if possible. If you’re staying in a high-altitude city or resort, look for transportation to lower ground. Moving to lower elevation, even slightly, is the top priority. Seek medical attention as soon as possible.

nnnnnn

5. How to Prevent Altitude Sickness

nnnn

Proper preventive measures can significantly reduce the risk of developing altitude sickness. Here we’ll explain prevention strategies in detail, from the planning stages through actual activity at high altitude.

nnnn

5-1. Prevention During Planning

nnnn

The fundamental principle of altitude sickness prevention is “don’t rush.” The body needs time to adapt to low-oxygen environments, and allowing sufficient time for this adaptation is the most important preventive measure.

nnnn

Allow Time for Acclimatization

nnnn

Ideally, you should spend 1-2 days at elevations above 2,500 meters (8,200 feet) to let your body adjust before ascending higher. However, travel and climbing schedules are limited, and not everyone can afford this luxury.

nnnn

Still, taking whatever time you can for acclimatization is important. For Mount Fuji climbs, for example, rather than starting to climb immediately upon arriving at the 5th Station, rest there for 1-2 hours to let your body adjust to the altitude. Many people skip this “5th Station rest” and start climbing right away, but this simple step can make a significant difference in altitude sickness risk.

nnnn

Avoid Rushed Schedules

nnnn

“Bullet climbing” should be particularly avoided. The style of departing from the 5th Station at night, climbing through the night, and descending by morning after seeing the sunrise leaves no time for the body to rest and greatly increases altitude sickness risk.

nnnn

If possible, plan a schedule that includes an overnight stay in a mountain hut, allowing your body to rest while climbing. Climbing during daylight hours is also preferable for safety, as nighttime brings colder temperatures and reduced visibility.

nnnn

Be Mindful of Ascent Rate

nnnn

A well-known guideline for altitude sickness prevention is to “limit daily elevation gain to 500 meters (1,600 feet).” Of course, this is just a guideline and doesn’t apply to all situations, but the principle of avoiding rapid altitude gain is worth remembering.

nnnn

When flying directly to high-altitude cities abroad, following this guideline is physically impossible. In such cases, avoid strenuous activity on the first day and take it easy to reduce stress on your body.

nnnn

5-2. Prevention Through Health Management

nnnn

Managing your health before departure is also essential for altitude sickness prevention.

nnnn

Get Adequate Sleep

nnnn

Sleep deprivation is one factor that increases altitude sickness risk. You may have trouble sleeping the night before a climb or high-altitude trip due to excitement, but try to get as much sleep as possible. At minimum, maintain a regular lifestyle in the days leading up to departure to keep your body in good condition.

nnnn

Stay Well 수분 섭취d

nnnn

At high altitude, the body loses more water due to dry air, sweating from exercise, and faster breathing. 탈수 can worsen altitude sickness symptoms, so consciously maintain fluid intake.

nnnn

As a guideline, it’s recommended to drink 250-500ml (about 8-17 oz) of fluids per hour during high-altitude activity. Rather than drinking large amounts at once, frequent small sips are more effective. Also, by the time you feel thirsty, you’re likely already mildly dehydrated, so drink consciously before you feel thirst.

nnnn

Avoid Alcohol and Sleeping Pills

nnnn

Alcohol promotes dehydration, reduces sleep quality, and suppresses breathing. All of these increase altitude sickness risk, so it’s advisable to avoid alcohol at high altitude, at least until your body has acclimatized. While “celebrating with a beer at the summit” may be appealing, it’s not advisable from an altitude sickness prevention standpoint.

nnnn

The same applies to sleeping pills. Many sleeping pills suppress breathing, and their use at high altitude may increase altitude sickness risk. Avoid relying on sleeping pills just because you’re having trouble sleeping at high altitude.

nnnn

Avoid Strenuous Exercise the Day Before

nnnn

Exhausting yourself with strenuous exercise the day before climbing or high-altitude travel not only reduces your performance on the day but may also make you more susceptible to altitude sickness. Take it easy the day before departure to conserve your energy.

nnnn

5-3. Prevention During Climbing or High-Altitude Stay

nnnn

Your behavior after reaching high altitude is also important for altitude sickness prevention.

nnnn

Move Slowly

nnnn

“Don’t rush when climbing” is a cardinal rule of altitude sickness prevention. Specifically, the guideline is to maintain a pace that allows normal conversation while walking. If you’re so breathless that you can’t talk, you’re moving too fast.

nnnn

At the beginning of a climb, when you still have energy, you may be tempted to walk quickly, but maintaining a slow pace from the start also helps conserve energy for later. Don’t rush; keep your own pace.

nnnn

Take Frequent Breaks

nnnn

Regular breaks are important not only for resting your body but also for allowing it to adjust to the altitude. Stop to rest every 30 minutes to an hour, and take time for hydration and light snacks.

nnnn

Deep breathing during breaks is also effective. Consciously breathing deeply and exhaling slowly promotes oxygen intake and helps your body adapt.

nnnn

Stay Alert to Changes in Your Condition

nnnn

At high altitude, always pay attention to changes in how you feel. Don’t miss early symptoms like headache, dizziness, or nausea. Rather than thinking “It’s probably nothing” or “It’ll get better if I push through,” if you feel even slightly unwell, either rest, slow your pace, or consider turning back.

nnnn

When traveling in a group, people often push themselves because they don’t want to inconvenience others or fall behind. However, letting altitude sickness worsen will ultimately cause greater inconvenience. If you feel unwell, don’t hesitate to tell your companions.

nnnn

5-4. It Can Still Happen Despite Prevention

nnnn

While we’ve covered various prevention methods, unfortunately, following all of them doesn’t completely eliminate the possibility of altitude sickness. Susceptibility to altitude sickness varies between individuals and is also affected by current health and condition.

nnnn

Even someone who climbed the same mountain before without any problems may develop altitude sickness depending on their condition at the time. And some people may be constitutionally more prone to altitude sickness despite thorough prevention efforts.

nnnn

What’s important is not to become discouraged thinking “Why did this happen when I was so careful?” but to respond appropriately when symptoms appear. In the next section, we’ll explain what to do if you develop altitude sickness.

nnnnnn

6. What to Do If You Develop Altitude Sickness

nnnn

Even with careful attention to prevention, altitude sickness can still occur. If you or a companion develops altitude sickness symptoms, how should you respond?

nnnn

6-1. First Steps to Take

nnnn

Stop Pushing Yourself

nnnn

When altitude sickness symptoms appear, the most important thing is to stop pushing yourself. Continuing to climb or engage in activity while ignoring symptoms can lead to deterioration.

nnnn

It’s natural to think “I’m almost at the summit” or “I’ve come this far,” but severe altitude sickness can be life-threatening. The mountain isn’t going anywhere. You can try again after your condition improves. Prioritize your own body first.

nnnn

Descend to Lower Elevation

nnnn

The most effective treatment for altitude sickness is descending to lower elevation. Simply moving from higher to lower ground can dramatically improve symptoms.

nnnn

As a general guideline, symptoms often improve after descending 300-500 meters (1,000-1,600 feet). However, severe cases may require descending much further.

nnnn

If you’re climbing, stop attempting to reach the summit and begin descending. If you’re at a mountain hut, consider moving to a lower elevation hut if possible. If you’re staying in a high-altitude city or resort, look for ways to get to lower ground.

nnnn

휴식 and Stay Calm

nnnn

When descending isn’t feasible (for example, when it’s nighttime and travel would be dangerous), the next best option is to rest where you are. Lie down, relax your body, and focus on deep breathing.

nnnn

During this time, carefully observe whether symptoms improve or worsen. If symptoms trend toward improvement, continue resting and prepare for descent the next morning. If symptoms worsen, you may need to consider ways to move safely even at night.

nnnn

Take in Fluids and Nutrition

nnnn

When experiencing altitude sickness symptoms, appetite tends to decrease, but dehydration and low blood sugar can worsen symptoms. Within reason, try to consume small amounts of fluids and carbohydrates.

nnnn

6-2. Altitude Sickness Medication: Diamox (Acetazolamide)

nnnn

Diamox (generic name: acetazolamide) is an effective medication for both treating and preventing altitude sickness. It is one of the few medications with established medical evidence for altitude sickness.

nnnn

What Is Diamox?

nnnn

Diamox was originally developed for treating glaucoma and as adjunct therapy for epilepsy, but it has been found to be effective for preventing and treating altitude sickness. It belongs to a class of drugs called carbonic anhydrase inhibitors, which work by affecting the body’s acid-base balance to help it adapt to high-altitude environments.

nnnn

How It Works

nnnn

Normally, our bodies are designed to increase breathing when blood carbon dioxide levels rise. However, in low-oxygen high-altitude environments, the body tries to breathe excessively to compensate, expelling too much carbon dioxide and causing the blood to become alkaline. In this state, the body responds by thinking “carbon dioxide is low, so I should breathe less,” which interferes with the adaptation process.

nnnn

Diamox works by inhibiting the reabsorption of bicarbonate ions in the kidneys, keeping the blood slightly acidic. This allows the body to continue stimulating breathing, which improves oxygen uptake. Simply put, Diamox promotes and accelerates the body’s adaptation to high altitude.

nnnn

Preventive Use

nnnn

Diamox can also be used preventively for altitude sickness. It’s started 1-2 days before climbing or high-altitude travel and continued during the high-altitude stay or until sufficient acclimatization is achieved.

nnnn

Preventive use is said to significantly reduce the risk of developing altitude sickness. It may be particularly recommended for those who have experienced altitude sickness before, those planning rapid altitude gain, and those who won’t have sufficient time for acclimatization.

nnnn

Therapeutic Use

nnnn

Diamox can also help reduce symptoms when altitude sickness has already developed. Of course, descending to lower altitude is the priority in severe cases, but combining Diamox can speed recovery.

nnnn

Side Effects and Precautions

nnnn

While Diamox is a relatively safe medication, you should be aware of some side effects.

nnnn

The most common side effect is tingling or pins-and-needles sensations in the hands and feet (paresthesia). Many users experience this, but it’s usually mild and disappears when the medication is stopped. The medication also has diuretic effects, increasing urination frequency. This can increase dehydration risk at high altitude, so you need to be more conscious about fluid intake.

nnnn

Some people also experience altered taste of carbonated beverages (finding them unpleasant). This is due to the medication’s mechanism and isn’t cause for concern, but if you were looking forward to a beer at the summit, it may taste different.

nnnn

Rarely, more serious side effects such as severe allergic reactions can occur. Those with allergies to sulfa drugs (sulfonamide-class medications) in particular may experience similar allergic reactions to Diamox and should avoid taking it.

nnnn

Prescription Required

nnnn

In Japan, Diamox is classified as a prescription medication and cannot be purchased freely at pharmacies or drugstores. You need to see a doctor and obtain a prescription.

nnnn

In some countries, it may be available over the counter, but self-medicating carries risks. Those with underlying medical conditions, those taking other medications, and those who are pregnant or breastfeeding should always consult a doctor before use.

nnnn

Diamox Prescriptions at Our Clinic

nnnn

Our clinic provides Diamox prescriptions for the prevention and treatment of altitude sickness. If you’re planning to climb Mount Fuji or travel to high-altitude destinations, or if you’ve experienced altitude sickness before and want to discuss measures for your next trip, please feel free to consult with us.

nnnn

We also offer online consultations, so you can receive advice and prescriptions from the comfort of your home. Consulting well before your departure date will allow you to head to high altitude with peace of mind.

nnnnnn

6-3. When to Seek Medical Attention

nnnn

We recommend seeking prompt medical attention in the following situations:

nnnn

Symptoms Don’t Improve with 휴식

nnnn

If symptoms don’t improve after descending and resting, or if symptoms persist for more than 24 hours, you may need medical evaluation and treatment. There may also be causes other than altitude sickness.

nnnn

Symptoms Are Getting Worse

nnnn

If symptoms gradually worsen despite resting, this is a dangerous sign. Seek immediate medical attention if headaches are intensifying, vomiting is becoming repetitive, or breathlessness is increasing.

nnnn

Warning Signs of Severe Illness Are Present

nnnn

If even one of the severe warning signs mentioned earlier (severe headache, shortness of breath at rest, coughing with pink sputum, inability to walk straight, altered consciousness) is present, this is an emergency. Descend as quickly as possible while arranging transport to a medical facility.

nnnn

Symptoms Persist After Returning from High Altitude

nnnn

If symptoms continue for several days after returning to low elevation from high altitude, causes other than altitude sickness should be considered. As explained in the next section, other conditions can produce symptoms similar to altitude sickness, so medical evaluation is recommended.

nnnn

7. Is It Really Altitude Sickness?

nnnn

While we’ve covered altitude sickness in detail, there are actually many other conditions that can cause similar symptoms. In this section, we’ll discuss other conditions that may be suspected based on the various symptoms of altitude sickness.

nnnn

You may need to consider causes other than altitude sickness in the following situations:

nnnn

• You have similar symptoms but haven’t been to high altitude recently
• Symptoms persist long after returning from high altitude
• Symptom patterns differ from typical altitude sickness progression
• You have other symptoms as well

nnnn

7-1. Conditions Suggested by Headache

nnnn

Headache is an extremely common symptom with various causes. Conditions other than altitude sickness that may cause headaches include:

nnnn

Migraine

nnnn

Migraines are characterized by throbbing, pulsating pain, often on one side of the head, though they can affect both sides. Sensitivity to light and sound, as well as nausea, are also common, which can make it difficult to distinguish from altitude sickness.

nnnn

Some migraine sufferers experience visual disturbances called “auras” (such as seeing zigzag lights) before the pain begins. Stress, sleep deprivation, certain foods, and menstrual cycles can trigger migraines, so if any of these factors apply, migraine may be a possibility.

nnnn

Tension Headache

nnnn

Tension headaches feel like pressure squeezing the entire head, or like wearing a tight helmet. They’re often associated with shoulder and neck stiffness and tend to occur after desk work or long periods of driving.

nnnn

During travel, long periods in the same position are common, creating conditions favorable for tension headaches. A headache experienced at high altitude might actually be caused by posture during travel.

nnnn

Sinusitis

nnnn

Sinusitis is inflammation of the sinuses (the air-filled spaces around the nose). It can cause pressure or pain in the forehead, cheeks, and behind the eyes, which may be perceived as a headache. It’s often accompanied by nasal congestion, yellow or green nasal discharge, and facial pressure.

nnnn

Air pressure changes during flights can worsen sinusitis symptoms, so headaches after flying can be confused with altitude sickness.

nnnn

탈수

nnnn

탈수 can cause headaches. At high altitude, increased water loss from dry air and exercise makes dehydration more likely. Signs of dehydration include dark urine, infrequent urination, and dry mouth.

nnnn

Adequate hydration to resolve dehydration may improve headaches. It can be difficult to determine whether a headache at high altitude is purely from altitude sickness, dehydration, or both, but hydration is important regardless.

nnnn

Meningitis (Emergency)

nnnn

Meningitis is inflammation of the membranes covering the brain and spinal cord, causing severe headache. Characteristic symptoms include fever, neck stiffness (inability to touch chin to chest), and sensitivity to light.

nnnn

Meningitis is a life-threatening emergency. If these symptoms are present, consider the possibility of meningitis rather than altitude sickness and seek immediate medical attention.

nnnn

7-2. Conditions Suggested by Nausea and Vomiting

nnnn

Acute Gastroenteritis/Food Poisoning

nnnn

One of the most common causes of nausea and vomiting is acute gastroenteritis or food poisoning, which occurs after consuming food or water contaminated with viruses or bacteria. Diarrhea is common, and fever may also occur.

nnnn

During travel, dietary changes make gastrointestinal problems more likely. When experiencing nausea at high altitude, consider not only altitude sickness but also the possibility of food-related causes.

nnnn

Motion Sickness

nnnn

Motion sickness causes nausea and dizziness during or after travel by car, bus, boat, or airplane. Travel to high altitude often involves long journeys on winding mountain roads, creating conditions favorable for motion sickness.

nnnn

It can be difficult to distinguish whether nausea upon arrival is an early symptom of altitude sickness or lingering motion sickness. It’s important to rest and observe how symptoms change.

nnnn

Heat Illness

nnnn

Heat illness occurs when the body’s temperature regulation fails in hot environments. It causes nausea, dizziness, headache, and fatigue—symptoms very similar to altitude sickness.

nnnn

While mountains may seem cool, climbing during summer days can lead to heat illness from direct sunlight and exercise-generated heat. It’s also possible to have both altitude sickness and heat illness simultaneously. Proper hydration, salt intake, and rest in cool environments are important.

nnnn

7-3. Conditions Suggested by Dizziness and Unsteadiness

nnnn

Benign Paroxysmal Positional Vertigo (BPPV)

nnnn

BPPV causes brief episodes of spinning vertigo when changing head position. This might happen when getting up in the morning, looking up, or turning over in bed—a strong sensation of the world spinning.

nnnn

This vertigo typically subsides within several seconds to a minute but can recur each time the head moves. It’s thought to be caused by small crystals called otoliths breaking loose and entering the semicircular canals of the inner ear.

nnnn

Meniere’s Disease

nnnn

Meniere’s disease is characterized by spinning vertigo, hearing loss, and tinnitus. Vertigo attacks can last from tens of minutes to several hours and may be accompanied by nausea and vomiting.

nnnn

Symptoms often affect one ear, and hearing may gradually decline with repeated vertigo attacks. If dizziness is accompanied by tinnitus or hearing loss, Meniere’s disease should be considered.

nnnn

Orthostatic Hypotension

nnnn

Orthostatic hypotension occurs when blood pressure drops suddenly upon standing from a seated or lying position. Characteristic symptoms include lightheadedness, unsteadiness, and vision darkening.

nnnn

탈수 makes orthostatic hypotension more likely. Combined with dehydration at high altitude, dizziness when standing may be more pronounced.

nnnn

Anemia

nnnn

Anemia is a condition where red blood cells or hemoglobin in the blood are insufficient. It causes dizziness, unsteadiness, fatigue, shortness of breath, palpitations, and pallor.

nnnn

When anemic, the body’s oxygen-carrying capacity is already reduced, making it even more vulnerable to low-oxygen environments at high altitude. Those who chronically experience dizziness or fatigue should check for anemia before traveling to high altitude.

nnnn

7-4. Conditions Suggested by Fatigue and Extreme Tiredness

nnnn

Sleep Deprivation/Jet Lag

nnnn

For international travel, jet lag-induced sleep deprivation may cause fatigue. It can take several days for the body clock to adjust to local time, during which you may not sleep well or may feel drowsy during the day.

nnnn

On high-altitude trips, jet lag effects and altitude sickness effects can overlap, making it difficult to determine which is causing the fatigue.

nnnn

탈수/Low Blood Sugar

nnnn

탈수 and low blood sugar can also cause significant fatigue. During travel, irregular eating and drinking schedules can lead to unknowing dehydration or low blood sugar.

nnnn

Fatigue caused by these factors improves with adequate hydration and properly timed meals.

nnnn

Hypothyroidism

nnnn

Hypothyroidism occurs when thyroid hormone production is insufficient. It causes chronic fatigue, easy tiring, weight gain, cold sensitivity, constipation, and dry skin.

nnnn

This condition often progresses gradually, and symptoms are often dismissed as “aging” or “just tired.” Those who chronically feel fatigued should consider getting tested.

nnnn

7-5. Conditions Suggested by Shortness of Breath and Difficulty Breathing

nnnn

Asthma

nnnn

Asthma is a condition where airway inflammation causes the airways to narrow, making breathing difficult. Characteristic symptoms include shortness of breath, coughing, and wheezing (whistling or squeaking sounds when breathing).

nnnn

Cold air and exercise can trigger asthma attacks, so they may occur during high-altitude climbing. Even those never diagnosed with asthma may experience asthma-like symptoms for the first time at high altitude.

nnnn

Pneumonia

nnnn

Pneumonia is an infection causing lung inflammation. It produces fever, cough, sputum, and shortness of breath. Symptoms can be similar to high altitude pulmonary edema, making distinction difficult.

nnnn

If fever is present, infectious disease (such as pneumonia) should be considered rather than altitude sickness.

nnnn

Heart Failure

nnnn

Heart failure is a condition where the heart’s pumping function is reduced, preventing adequate blood delivery to the body. Characteristic symptoms include shortness of breath, fatigue, swollen legs, and difficulty breathing when lying down at night.

nnnn

The low-oxygen environment at high altitude stresses the heart, so those with pre-existing heart conditions may experience worsening symptoms at high altitude. Those with a history of heart disease should consult a doctor before traveling to high altitude.

nnnn

Panic Attacks

nnnn

Panic attacks involve sudden intense anxiety accompanied by physical symptoms such as palpitations, shortness of breath, sweating, and trembling. You may feel like you “can’t breathe” or fear you might die.

nnnn

Anxiety about altitude sickness symptoms can trigger panic attacks, and panic attack symptoms can be mistaken for altitude sickness. If hyperventilation is involved, consciously slowing your breathing can improve symptoms.

nnnn

8. If You Have These Concerns, Please Consult Us

nnnn

If you’ve read this far and have concerns about your symptoms, or if you’re planning a trip to high altitude or mountain climbing, please consult our clinic.

nnnn

This Information Is for You If:

nnnn

• You’ve returned from high altitude but continue to have headaches, dizziness, fatigue, or other symptoms
• You became ill during or after climbing and don’t know the cause
• You have symptoms such as headache, nausea, dizziness, or shortness of breath and are worried it might be altitude sickness
• You’ve felt unwell since traveling somewhere recently and want to investigate the cause
• You want to consult in advance about an upcoming high-altitude trip or Mount Fuji climb
• You’ve experienced altitude sickness before and want to discuss preventive measures for your next trip

nnnn

What We Can Do

nnnn

At our clinic, we carefully listen to your symptoms and provide appropriate examinations and consultations as needed. When altitude sickness is likely, we provide treatment and prescriptions appropriate to the severity of symptoms. When causes other than altitude sickness are suspected, we can also refer you to appropriate specialists.

nnn