What Is High Altitude Sickness?
Altitude Sickness, or Acute Mountain Sickness (AMS), occurs when the body lacks sufficient oxygen to support normal breathing and bodily functions due to increased altitude.
During your trek in the higher region, the air's oxygen percentage decreases, leading to heightened physical issues. AMS can affect anyone who ventures to high altitudes without any specific factors determining who will experience it. This means no matter the age or experience level, and there is a great chance you will get altitude sickness during your high-altitude treks in Nepal.
Age, gender, and fitness level are irrelevant. This means even if you have not experienced it in similar conditions, you could still experience AMS. Moreover, trekkers can have varying acclimatization rates on different trips, even under identical conditions. Naturally, most reasonably fit people can ascend to approximately 3,000 meters without significant issues. However, every year, trekkers ruin their vacations by ignoring the signs of AMS in their bodies, leading to worse cases of AMS like High altitude cerebral edema and High altitude pulmonary edema.
When hiking to high-altitude regions like Everest Base Camp or Everest, the body requires time to adapt to oxygen levels. To compensate for the reduced oxygen in the air, the body increases the production of red blood cells. It carries more oxygen throughout the body, particularly to the muscles and brain.
Ascending too quickly to higher altitudes prevents the body from making necessary internal adjustments, leading to oxygen deprivation. Therefore, acclimatization is a gradual process, and although you might feel fine at first, AMS symptoms take time to manifest. With this in mind, AMS symptoms generally start after the first 10-24 hours, mainly if the body has insufficient time to acclimate beforehand.
Symptoms of Altitude Sickness to Watch Out For
AMS can affect trekkers at altitudes as low as 2,400 meters (8,000 feet). However, severe symptoms are uncommon below 3,700 meters (12,000 feet).
The primary triggers for AMS are reduced oxygen levels and physical exertion. When you reach 5,000 meters, the air pressure and oxygen available per breath are only 55% above sea level. Continuing your trek further, at 6,000 meters, it drops to less than half, greatly impacting the trekker's body's functioning.
AMS actually doesn't always develop gradually, like mild altitude-related symptoms such as headaches and breathlessness. In fact, it can suddenly and severely strike, severely hindering a hiker within minutes.
You probably did not expect this answer, but many trekkers and climbers may experience mild Acute Mountain Sickness (AMS) during acclimatization. Interestingly, this situation is more commonly observed in young and physically fit trekkers rather than old ones who approach mountain climbing with a fast-paced and unstoppable attitude, like superheroes. However, preventing altitude sickness is generally safer and more enjoyable by planning a suitable itinerary that allows for gradual adjustment to higher altitudes while ascending to your treks, either to Everest Base Camp or any other treks in Nepal. Still, you are free to descend as quickly as you desire.
The symptoms of AMS include:
- Nausea, vomiting, and loss of appetite.
- Disturbed sleep patterns, insomnia, and persistent headaches.
- Dizziness, feeling light-headed, confusion, disorientation, and an unsteady gait.
- Weakness, fatigue, tiredness, heavy legs, and slight swelling of the hands and face.
- Shortness of breath, irregular breathing, and reduced urine output.
- General feelings of discomfort and unease.
These symptoms should be taken very seriously because, if not treated, they can lead to the death of a climber or trekker. If any previous symptoms appear, the first thing to do is avoid further ascent, as more severe, even life-threatening complications may arise. And the only effective treatment for Altitude Sickness is immediately descending to lower elevations.
To prevent AMS, we include acclimatizing by ascending no more than 300 to 500 meters per day above 3000 meters during our treks. We also include proper rest and hydration as they are equally essential. Therefore, we, too, advise our clients to gentle ascent to avoid acute mountain sickness.
On this website, the trekking itineraries of all treks, like Everest Base Camp, Everest View trek, etc., are designed to ensure maximum enjoyment while minimizing potential hazards.
Who Is Most at Risk of Altitude Sickness?
Unfortunately, science has yet to identify specific markers that determine who may or may not experience altitude sickness while trekking. But altitude sickness change increases among trekkers who are unfit or first-time beginners.
The only reliable indicator to find out who most gets altitude sickness seems to be a previous history of symptoms, which suggests the possibility of experiencing them again. However, the absence of prior symptoms does not guarantee immunity.
Even athletes or individuals in excellent physical condition are not exempt from altitude sickness. In fact, trip leaders often express more concern for these individuals, as non-athletes tend to listen to their bodies and pay attention to symptoms, while athletes may attempt to push through the discomfort.
To explain more simply, altitude sickness can affect anyone. The longer you spend at higher altitudes, the less likely you are to experience its effects, but it can still strike anyone. It's important to note that altitude sickness can affect different people in varying ways and even affect the same individual differently from one trip to another, regardless of elevation.
Moreover, some trekkers struggle to acclimate to high altitudes despite taking all the necessary precautions. These individuals may experience headaches, fatigue, and shortness of breath, even following proper protocols.
Altitude sickness symptoms and difficulties can be categorized into three levels of elevated altitude:
High Altitude: 8,000 – 12,000 feet
Very High Altitude: 12,000 – 18,000 feet
Extremely High Altitude: 18,000+ feet
Trips and Altitude In Nepal
Our different hikes in Nepal, like the Langtang Valley trek, allow you to explore elevated destinations such as Tserko Ri – 5000 m / 16404 and Kyanjin Gompa – 3870 m / 12696 ft). It is common to experience mild symptoms of altitude sickness, too, in these areas. To ensure a smoother adjustment, we recommend arriving in Kyanjin Gompa a few days before the trip begins if your schedule allows for acclimatization.
This grants your body additional time to acclimate. Both the Tserko Ri – 5000 m / 16404 and Kyanjin Gompa – 3870 m / 12696 ft) reach altitudes ranging from 2750m (9,000ft) to 5000m ), with a challenging section at Tserko Ri. Although the hike covers a distance of only about 40km (25 miles), the altitude adds to the difficulty. You can conquer the challenge with a smile by taking it easy, maintaining a steady pace, and staying hydrated.
In the Gokyo Valley trek, you reach an elevation of 5,357 m / 17,575. Therefore, it can be a bit of a shock when you step outside the Lukla airport, especially if you encounter uphill terrain. During the Gokyo Valley Trek, we visit Gokyo ri at 5,357 m / 17,575. We will drive you to the airport in Kathmandu, then board a flight to Lukla. And From there, you'll be set up with a hiking journey.
Nepal, the home of our Himalayan adventures, offers a hiking experience in high-altitude settings. Both our Khumbu and Annapurna trips reach altitudes of approximately 3750m. The classic trek toEverest Base Camp (EBC) goes even higher, reaching 5,364m (17,598ft). To accommodate the altitude, the EBC hike spans 14 days and includes acclimatization periods, allowing your body to adjust gradually.
Our knowledgeable guides will take excellent care of you, and they carry portable oxygen tanks that can be used if necessary to temporarily alleviate symptoms of altitude sickness. Many trekkers complete this trek each year, reaching new heights in more ways than one. All you need is to be mindful, sensible, communicate any concerns, and take it easy. If any symptoms arise, it is important to descend until you feel better. Once your body has adjusted, you can resume your journey.
How to Prevent Altitude Sickness Before Your Trek
Nepal does not impose any specific health requirements for entry. Still, it's best to consult with your doctor before any high-altitude treks. Nepal boasts numerous mountains, each offering various trekking routes starting from their base camps.
Generally, altitude sickness can be categorized into total AMS, HAPE, and HACE. AMS is commonly encountered at select elevations, as determined by medical professionals. For example, you usually get AMs when traveling to more than 2400 m elevations. However, HAPE and HACE occur at more critical levels found at higher altitudes, especially during climbing expeditions like Everest.
Understanding the concept of altitude is the first measure of prevention.
As we know, every country has a unique geographical structure. Earth's elevation ranges from sea level to 8,848.87 meters (the summit of Mount Everest in Nepal).
For this discussion, altitude can be divided into three levels:
Level One: Altitudes ranging from 2,000 meters (6,562 feet) to 3,500 meters (11,500 feet).
Level Two: Altitudes between 3,500 meters (11,500 feet) and 5,500 meters (14,500 feet).
Level Three: Altitudes above 5,500 meters (18,000 feet).
The risk level significantly increases above 8,000 meters. During these high-altitude climbs, many mountaineers rely on oxygen cylinders when climbing Mount Everest's peak, which stands at 8,848.87 meters (29,031.7 feet).
The 3 Types of Altitude Sickness: AMS, HAPE, and HACE
Before executing safety measures or preventative measures, understanding HAPE (High Altitude Pulmonary Edema) and HACE (High Altitude Cerebral Edema) is important too. Once you surpass an elevation of 2000 meters, there is a possibility of experiencing psychological distress. So maintain a positive mindset and continue to trek further.
Acute Mountain Sickness (AMS)
Recent research indicates that altitude sickness, normally Acute Mountain Sickness (AMS), affects approximately 34% of travelers who ascend beyond 5000m in Nepal. AMS shares similarities with a hangover in less severe cases, causing trekkers to experience a throbbing headache, nausea, and overall exhaustion.
Fortunately, these symptoms can be relieved through relatively simple treatment measures, often allowing the body to acclimate by waiting a day. While AMS itself is rarely life-threatening, if left untreated, the symptoms can escalate to High-Altitude Cerebral Edema (HACE), leading trekkers toward its death.
Therefore, identify early signs of AMS and take appropriate steps to prevent the advance of the illness.
Common symptoms:-
Gastrointestinal (GI) symptoms: Upset stomach, loss of appetite, nausea, vomiting.
Fatigue or weakness: Feeling excessively tired and lacking energy beyond what is expected during a long day on the trail.
Dizziness: Sensation of lightheadedness.
Insomnia: Difficulty sleeping, mainly characterized by extreme disturbances at high altitudes.
Treatment options:
Descend: Symptoms typically subside if you descend by 300-1000m. It is essential to wait until you feel entirely better before ascending again.
Dexamethasone (Decadron): An anti-inflammatory corticosteroid known for its high effectiveness in treating AMS. Take 4mg every 6 hours.
Acetazolamide (Diamox): Primarily used for preventing AMS, but can also be taken in higher doses (250mg every 12 hours) to treat AMS. However, if available, Dexamethasone is still the preferred option.
High Altitude Pulmonary Edema (HAPE)
High Altitude Pulmonary Edema (HAPE) is a dangerous condition characterized by fluid buildup in the lungs. It can have severe consequences, even leading to fatalities. One of the most common indications of altitude sickness is heart failure.
Recognizing the Signs and Symptoms of HAPE:
- Bluish discoloration of the skin or lips.
- Difficulty breathing, which persists even during rest.
- The feeling of tightness or constriction in the chest.
- Respiratory infection is accompanied by producing foamy, pink, or white fluids (sputum).
- Fatigue and weakness.
Treatment options:
-Descend to a lower altitude without delay.
- Consider using nifedipine, which helps alleviate chest pain and improve breathing. It is commonly included in medical supplies for expeditions.
- If available, administer bottled oxygen to assist with breathing.
High-Altitude Cerebral Oedema (HACE)
High-Altitude Cerebral Edema (HACE) is a severe condition that can occur if Acute Mountain Sickness (AMS) symptoms are left untreated while trekking. HACE involves the swelling of the brain, and it should be taken very seriously. If left untreated, it can quickly lead to a coma or death of a climber or trekker. This is why addressing AMS promptly before it progresses to HACE is crucial.
HACE generally occurs at elevations above 3500 meters after a few days of exposure. Moreover, HACE is much rarer than AMS, with less than 1% of trekkers developing cerebral edema between 4200-5500 meters. Nevertheless, be prepared to identify the symptoms of HACE and respond swiftly before anything worse happens.
Symptoms
Severe AMS symptoms: Headaches, feelings of nausea, vomiting, fatigue, dizziness, difficulty sleeping, and other related symptoms.
Impaired mental state: Some trekkers have described this as a sensation similar to being drunk, which may involve confusion, trouble speaking, or impaired judgment.
Ataxia: This refers to a loss of control over bodily movements.
Treatment options:
Descend: If you're experiencing High Altitude Cerebral Edema (HACE) symptoms, it's crucial to descend immediately by 300-1000 meters until you start feeling better.
Dexamethasone (Decadron): To address the inflammation associated with HACE, take 8mg of Dexamethasone with food, followed by 4mg every 6 hours.
Oxygen: If descending isn't possible or you cannot do so, it becomes necessary to receive supplemental oxygen.
What to Do If Trekkers Get Altitude Sick in the Himalayas of Nepal?
It's better for trekkers if they do not get altitude sickness or any form of altitude sickness at all. But still, if any trekkers get altitude sickness while trekking in the Himalayas of Nepal, then preventing acute mountain sickness (AMS) is a must. For this, experts recommend maintaining a slow and steady walking pace above 2500 meters (8202 ft) while not exceeding an elevation gain of 300 meters (984 ft) daily. Once we reach an altitude above 4000 meters (13123 ft), the daily climb rate should be limited to 150 meters (492 ft).
However, when going on treks in Nepal, such as the Annapurna Base Camp Trek, Everest Base Camp Trek, Annapurna Circuit Trek, and others, the daily hiking distances typically range from 350 meters (1148 ft) to 500 meters (1640 ft), depending on the itinerary provided by the trekking agencies.
To fight dryness and moisture-related issues, taking short walks and staying well-hydrated by drinking plenty of water is recommended.
If symptoms of altitude sickness begin to manifest, it is crucial not to continue ascending uphill. Instead, staying at a lower elevation and preparing for the following day is advisable. Whenever possible, seek guidance from a healthcare professional or rely on the expertise of your experienced trekking guide/leader for appropriate advice.
How to Prevent Altitude Sickness During Your Trek
There are several clear and sensible methods to prevent severe altitude sickness from spoiling your trip (or, even worse, causing harm). Some of these should be considered during the trip planning phase (like allocating extra days to your schedule). Additionally, medications are available, and specific precautions to follow contribute to preventing altitude sickness while trekking in Nepal.
Acclimation During Hike
Spending time at a moderate altitude beforehand is highly beneficial to prepare your body for the challenges of high-altitude trekking. We recommend allocating at least two days in Namche Bazaar or a similar high-altitude town before trekking to EBC or Gokyo Lake. In addition, undertake a few short acclimatization hikes in the surrounding area before going on such a high-altitude trek.
Gradual Ascent
The ascent rate is one of the most important risk factors for developing altitude sickness. So limiting your net elevation gain to 500m or less per day (after reaching 3000m) will decrease the likelihood of getting sick. Most guided tours consider this already, but if you’re embarking on a solo trek, it’s really important to sit down and carefully plan your route to avoid climbing too quickly.
Trek High, Sleep Low
There’s something to be said for “trekking high, sleeping low,” or camping at a lower altitude than your high point for the day to help minimize altitude sickness. You should also try to increase your sleeping altitude gradually, no more than 600m per day if possible.
Final Say
So here is the answer to all your questions related to altitude sickness. Our intention is not to frighten you but rather to inform you about the symptoms so you can exercise extra caution when venturing above 2,500 meters during treks like in EBC or ABC. If you suspect you may be experiencing altitude sickness, we strongly advise you to seek immediate medical attention.
