Altitude, or acute mountain sickness (AMS), is a common health concern for individuals ascending to high altitudes. Altitude sickness and prevention are two important aspects for trekkers to know before the high-altitude trek. Altitude sickness occurs when lower atmospheric pressure at high altitudes reduces oxygen availability. Symptoms can range from mild headaches and nausea to serious conditions like high-altitude pulmonary edema (HAPE) and high-altitude cerebral edema (HACE).
Preventing altitude sickness involves allowing time for acclimatization, especially above 2,500 meters, by ascending gradually. Key measures include staying hydrated, avoiding alcohol and strenuous activities initially, and recognizing early warning signs. Trekkers can also take medications like Diamox and Acetazolamide, which can prevent or minimize the symptoms of altitude sickness. So, let’s look at the types of altitude sickness and how to prevent them.
Table of Contents
Types of altitude sickness
AMS ( Acute Mountain Sickness (Normal Risk)
Acute mountain sickness (AMS), or altitude sickness, is a common ailment that can affect people who ascend to high altitudes too quickly. It is caused by reduced air pressure and lower oxygen levels at higher elevations. Essentially, your body struggles to adapt to the decreased availability of oxygen. The symptoms of acute mountain sickness can be either mild, like nausea, headache and five, or extremely severe, where it can even be fatal.
The severity of AMS depends on several factors, including the altitude reached, the speed of ascent, and individual susceptibility. While mild cases often resolve with rest and acclimatization at the current altitude, more severe cases may require descent to a lower elevation. In extreme situations, AMS can progress to life-threatening conditions like high-altitude pulmonary edema (HAPE) or high-altitude cerebral edema (HACE), which involve fluid buildup in the lungs or brain, respectively. Therefore, gradual ascent and awareness of symptoms are crucial for preventing serious complications.
HAPE ( High Altitude Pulmonary Edema) ( Medium Risk)
High-altitude Pulmonary Edema is a type of lung swelling that can happen to people not used to high altitudes, especially above 2,500 meters. It is important to recognize the symptoms early and to descend immediately for effective treatment. Despite early signs of altitude sickness, many trekkers push themselves too hard. Some even choose to ride horses to higher altitudes, which is risky and life-threatening.
The Symptoms of HAPE can include shortness of breath, a persistent dry cough, chest tightness, and fatigue. If left untreated, it can progress rapidly to severe respiratory distress, cyanosis (blue discoloration of the skin), and even death. The primary treatment for HAPE is immediate descent to a lower altitude and supplemental oxygen. In severe cases, medication may also be necessary.
HACE ( High Altitude Cerebral Edema) ( High Risk)
High Altitude Cerebral Edema (HACE) is a severe and potentially fatal form of altitude sickness. It occurs when the brain swells with fluid due to the reduced oxygen levels found at high altitudes. This condition is considered a medical emergency, as it can rapidly progress to coma and death if not treated promptly. HACE typically develops after a rapid ascent to altitudes above 4,000 meters (approximately 13,000 feet), though it can occur at lower elevations in susceptible individuals.
Key symptoms of HACE include severe headaches, loss of coordination (ataxia), confusion, disorientation, and altered mental status. These symptoms often follow or are accompanied by symptoms of Acute Mountain Sickness (AMS). The primary treatment for HACE is immediate descent to a lower altitude. Supplemental oxygen and medications like dexamethasone can also be administered to reduce brain swelling. Prevention strategies focus on gradual ascent to allow the body to acclimatize to the reduced oxygen levels.
Symptoms of High Altitude Sickness
AMS (Acute Mountain Sickness)
These are some fo the symptoms of the Acute Mountain sickness, which trekkers might experience during their high altitude expedition of Nepal.
Headache
A headache is often the first and most prominent symptom of AMS. It can range from a mild, dull ache to a severe, throbbing pain. This headache is typically worsened by exertion and may be accompanied by nausea or dizziness. It’s important to note that a headache at altitude, especially if combined with other symptoms, should be treated as a potential sign of AMS.
Fatigue/ Tiredness
Fatigue and tiredness are also common symptoms of AMS. Individuals may feel unusually weak, lacking the energy they typically possess at lower altitudes. This fatigue can manifest as a general sense of lethargy, making even simple physical activities feel exceptionally strenuous. The body’s increased effort to obtain sufficient oxygen contributes significantly to this overwhelming sense of tiredness.
Shortness of breathing
Shortness of breath, particularly during exertion, is another hallmark symptom of AMS. At higher altitudes, the reduced partial pressure of oxygen makes it harder for the lungs to extract oxygen from the air. This results in a feeling of breathlessness, even during mild activity. While some shortness of breath is normal at altitude, a significant increase or persistent breathlessness should be considered a warning sign.
Loose of Appetite
Those experiencing AMS frequently report loss of appetite. When a person goes to a high altitude, their body can react in ways that upset normal digestion. This can cause nausea and make them less hungry. As a result, they may feel more tired and weak because good nutrition is crucial for adjusting to high-altitude conditions.
Sleeping Disturbance
Many people with Acute Mountain Sickness (AMS) have trouble sleeping especially in the cold, freezing temperatures like at the top of the Upper Mustang trek. They may experience insomnia or wake up frequently during the night. Changes in breathing and other physical effects from being at high altitude can interrupt sleep patterns, making it hard to get restful sleep. The lack of sleep will create a more problematic situation for trekkers, as they will be more fatigued, have headaches, and experience overall discomfort, which might even worsen the symptoms of AMS.
HAPE (High Altitude Pulmonary Edema)
Shortness of breathing even after resting
This is a critical indicator of worsening HAPE. Initially, shortness of breath may only occur during exertion, but as the condition progresses, it becomes present even when the individual rests. This signifies that fluid buildup in the lungs is severely impairing oxygen exchange.
Dry cough
A dry cough is often one of the early symptoms of HAPE. It may start out as a mild irritation but can worsen as fluid accumulation in the lungs increases.
Severe Cough
As HAPE progresses, the dry cough can become a severe cough and a wet cough that produces pink frothy sputum. This is a sign of serious fluid accumulation in the lungs.
Very Tired
Extreme fatigue and weakness are common symptoms of HAPE. The reduced oxygen levels in the blood caused by fluid in the lungs lead to a significant decrease in energy.
Elevated Heart
An elevated heart rate (tachycardia), particularly a pulse above 110 beats per minute, is a common sign of HAPE. The heart works harder to compensate for the reduced oxygen levels in the blood.
Cyanosis
Cyanosis, the bluish discoloration of the skin, lips, and fingernails, indicates a severe lack of oxygen in the blood. This is a very serious sign of advanced HAPE.
Hyperthermia
An elevated body temperature can occur in HAPE. Though it is not always a high fever, the temperature is generally not exceedingly high.
HACE (High Altitude Cerebral Edema)
Severe Headache
A severe headache is often one of the initial and prominent symptoms of HACE. Unlike a typical headache, this one is persistent and intensifies with increasing altitude. It’s a sign that the brain is experiencing increased pressure. This headache will not be relieved by common over the counter pain medications. This symptom is a key indicator that a person is worsening from Acute Mountain Sickness(AMS) into HACE.
Vomiting
Vomiting in HACE is not simply nausea; it’s often forceful and repetitive. This symptom arises from the increased pressure within the skull, which stimulates the vomiting center in the brain. It is a sign that the brain is under severe duress.
Ataxia ( Walking as a Drunker)
Ataxia, or loss of coordination, is a crucial diagnostic sign of HACE. Individuals affected by ataxia will exhibit an unsteady gait, appearing as if they are intoxicated. This loss of balance and coordination results from the brain’s swelling, affecting the areas responsible for motor control. This is a very important sign that someone has progressed to HACE.
Mental Confusion
Another symptom of the HACE is mental confusion, which means trekkers won’t be able to function properly. They will suffer from disorientation, confusion, and impaired judgment. Furthermore, it will be tougher for them to think, remember, and make simple decisions.
Irritable
This symptom reflects a change in personality and behavior. Individuals experiencing HACE may become unusually irritable, agitated, or withdrawn. They may resist assistance or become uncharacteristically uncooperative. This is also a sign of the brain not functioning correctly.
Coma/ Unconsciousness
In the most severe cases, HACE can progress to coma or unconsciousness. This occurs when the brain swelling becomes so severe that it disrupts the brain’s ability to maintain consciousness. This is a life-threatening situation and requires immediate descent to a lower altitude and emergency medical care.
How to Prevent Altitude Sickness?
Altitude sickness is an extremely difficult condition for trekkers. They fall sick after failing to adjust to the conditions and oxygen level of the high altitude, especially over 3000m. Altitude sickness can completely halt the trek and send trekkers back, which is why it is important to follow some preventive measures.
Acclimatize
Gradual acclimatization is the most crucial step in preventing altitude sickness. This process allows your body time to adjust to the decreasing oxygen levels. The body responds by producing more red blood cells to carry oxygen, which takes time. Therefore, it’s essential to plan your ascent with rest days and gradual increases in altitude.
Slowly ascend
A slow ascent is vital for proper acclimatization. Avoid rapid gains in altitude, especially above 3,000 meters (10,000 feet). Aim for a gradual increase in elevation each day, allowing your body to adapt. This means you will gain enough rest and generate enough
Stay Hydrated ( around 3-5 liters)
Another way to prevent altitude sickness is to stay hydrated throughout the trek. Trekkers should drink at least 3 to 5 liters daily to control the liquid they will lose. So whenever you have the chance, make sure you feel of the drinking water bottle and drink
Carry Light Backpack
Excessive physical exertion can worsen altitude sickness. Carrying a heavy backpack puts extra strain on your body, making it harder to adapt to the lower oxygen levels. Lighten your load by packing only essential items and considering hiring a porter if necessary.
Climb every day 300m
A general guideline is to not ascend more than 300 meters (1,000 feet) per day above 3,000 meters. This allows your body to adjust incrementally to the changing altitude. Adhering to this rule can minimize the strain on your body and reduce the likelihood of developing altitude sickness.
Climb high, sleep low
In this strategy, the trekkers should go to a higher altitude during the day to help their body adjust but then come back down to a lower altitude for sleep. This way, you can benefit from being at a higher altitude without the extra strain of sleeping there.
Travel with Group
Traveling with a companion or group is important for your safety, especially at high altitudes. If you or someone in your group gets altitude sickness, having others around can help provide support and seek medical assistance. This way, someone can monitor your condition and help if needed.
Avoid Sleeping Tablets, Alcohol, Smoking
Avoid alcohol, smoking, or sleeping pills while at high altitudes. These substances can slow down your breathing, making it harder for your body to get enough oxygen. They can also hide the symptoms of altitude sickness and delay needed treatment. It’s important to let your body adjust to the altitude without complicating things further.
Risk Factors for Altitude Sickness
Altitude sickness, also called acute mountain sickness (AMS), can happen to anyone who climbs to high altitudes too quickly. It happens because the air pressure is lower at higher altitudes, which means there is less oxygen available. Some people are more likely to experience this condition than others. Here are key risk factors to keep in mind:
Acclimatize
Altitude sickness happens mainly because you climb too quickly. When you go to a higher place too fast, the air pressure decreases, which lowers the amount of oxygen available. This means your lungs receive less oxygen with each breath. Your body needs time to adjust to this change by making more red blood cells. If you go up too fast, your body can’t handle it, and you may feel symptoms like headaches, nausea, and tiredness. That’s why climbing gradually and taking rest days is important to help your body acclimatize.
High Altitude
The severity of altitude sickness is directly correlated with the elevation reached. As you ascend, the air becomes progressively thinner, and the available oxygen decreases. At very high altitudes, even well-acclimatized individuals can experience severe forms of altitude sickness. The higher you go, the greater your body’s challenge in obtaining sufficient oxygen. Therefore, those going to extreme altitudes, such as above 5,000 meters (16,400 feet), are at the highest risk.
Previous History of Altitude Sickness
Having experienced altitude sickness in the past significantly increases your susceptibility to it in the future. While acclimatization provides some protection, individual physiology plays a role. If your body has previously struggled to adapt to low oxygen levels, it’s more likely to do so again. This doesn’t mean you can’t go to high altitudes, but it emphasizes the need for extra caution, slower ascents, and possibly preventative measures like medication.
Individual Susceptibility
People react differently to high altitude. Even those with similar fitness levels and climbing experiences can have different outcomes. Some may get altitude sickness while others do not. This difference comes from things like genetics and how our bodies handle oxygen, but many of these factors aren’t fully understood yet. Some individuals are simply more sensitive to changes in oxygen levels. Because it’s hard to predict who will get sick, everyone should know the signs of altitude sickness, regardless of how fit they think they are or what they have experienced in the past.
Physical Exertion
Physical activity at high altitudes requires more oxygen, which puts extra strain on your body. You may face altitude sickness if you exercise too hard before your body adjusts. Overdoing it can worsen symptoms and slow your body’s ability to adapt. It’s important to take it easy during the first few days at high altitude and gradually increase your activity level as you adjust. This helps your body focus on getting used to the altitude rather than on heavy exercise.
Annapurna Circuit Trek
10 Days
Adventure Treks
USD675 per person
Langtang Valley Trek
7 Days
Adventure Treks
USD399 per person
Annapurna Base Camp Trek – 7 Days
7 Days
Trekking
USD449 per person
Conclusion
Altitude sickness is one of the significant risks for anyone going to the high altitude trekking in Nepal. No matter the experience or fitness level, anyone can suffer from this illness. So, trekkers planning to experience high altitudes must plan accordingly and follow some preventive measures. Taking medications like Diamox can also reduce the risk of altitude sickness.
It’s important to understand how altitude affects the body. By learning about these challenges and using prevention strategies, people can enjoy high-altitude areas while lowering their risk of health problems. Take time to acclimatize and pay attention to how your body feels. This is vital for a safe and enjoyable experience at high altitudes.
