Did you know that nearly 50% of trekkers above 30,000 m experience some form of altitude sickness? Trekking to the Himalayas not only comes with breathtakingly beautiful moments but also the inevitable risk of altitude sickness, i.e., AMS (Acute Mountain Sickness). Here's everything you need to know about altitude sickness while trekking.
What is Altitude Sickness?
Altitude sickness is a reaction of the body to low oxygen levels at high elevations. When these reactions are ignored it can turn into life-threatening conditions like HAPE (High Altitude Pulmonary Edema) and HACE (High Altitude Cerebral Edema).
When the ascent is rapid, our bodies fail to acclimatize adequately to the reduced oxygen levels at higher altitudes. It is more common with elevations above 8,000 ft (2,500 m), but the symptoms can occur even at lower altitudes, depending on the individual's adaptability and the speed of the ascent.
Exploring the world's highest peak can be a thrilling adventure that comes with a lot of risks associated with high-altitude travel. So trekkers and climbers must be aware of the causes, effects, and preventive measures of altitude sickness as it is one of the most common challenges for trekking in mountainous regions.
What are the causes of Altitude Sickness?
At sea level, atmospheric oxygen is about 21% and arterial oxygen saturation (SpO₂) is usually 95-99%. At 3,000 meters (9,843 ft), oxygen saturation can drop to 90% or lower, and at 5,000 meters (16,404 ft), it can fall below 70%.
The cause of altitude sickness shouldn’t be mistaken for a reduction of atmospheric oxygen, as it remains approximately 21%. However, it is caused due to hypobaric hypoxia, which is low oxygen due to reduced barometric pressure at high elevations.
Basically, the main cause of altitude sickness is atmospheric pressure, i.e., barometric pressure. The atmospheric pressure decreases as the altitude increases, and the oxygen levels are very low, which results in altitude sickness.
If you take enough acclimatization breaks or even live at higher altitudes the body will easily adapt to air pressure and oxygen levels and be used to it. Hence, local people from the Mountain region do not catch altitude sickness.
As soon as trekkers elevate more than 2,500 m (8,202 ft) they are more likely to suffer from altitude sickness. While you might be feeling hot due to the physical activity, the surrounding air is also extremely cold. Combine that with the harsh wind and shift of terrain from alpine to rugged ones, and it further increases the chances of getting altitude sickness.
Here are some of the things that you should avoid doing to decrease the risk of Acute Altitude Sickness:
- Giving Insufficient time for proper acclimatization
- Rapid Ascent to higher altitudes
- High-altitude trekking while going through medical problems like lung, heart, or nervous system disease.
- Live near sea level and travel to higher elevations spontaneously
- Drinking alcohol during acclimatization.
- History of altitude sickness
- Higher altitudes
What are the symptoms/signs of Altitude Sickness?
Altitude sickness can cause many symptoms, and these can vary depending on the severity. The symptoms of acute mountain sickness usually appear within the first day or so of reaching a high altitude. More severe forms like HAPE or HACE take longer to appear, usually between two and five days.
Most people will feel some effect of altitude, shortness of breath, and possibly light-headedness, which is fairly common. Acute mountain sickness is very different and normally involves a severe headache, sickness, and loss of awareness. In almost every potential case there are enough warning signs to take appropriate action.
AMS: This is the mildest and most common form of altitude sickness. These are some of the symptoms that you should expect but definitely not worry about. Here are some of the normal altitude symptoms that you should consider and try to mitigate, because every trekker will experience some or all of these, regardless of whether you ascend slowly.
- Insomnia
- Mild headache
- Weakness
- Fatigue / tired
- Loss of appetite
- Hard to breathe
- Runny nose
- Dry cough
- Dizziness
HAPE: High Altitude Pulmonary Edema (HAPE) is an accumulation of fluid in the lungs which can be very life-threatening. It is responsible for all the other mild and serious symptoms of altitude sickness and is often accompanied by a mild fever. The general treatment for this condition is using an oxygen supplement at 4 liters a minute, but using a PAC (Portable Altitude Chamber) bag treatment is also a good substitute. When there's no access to PAC bags or oxygen then descent will be a life-saving alternative. While not the most severe form, HAPE can lead to unconsciousness and very quick death.
HACE: High Altitude Cerebral Edema (HACE) is a medical condition in which the brain cells are fluid because of the physiological effects of trekking to high altitude. It usually appears in those who have Altitude Mountain Sickness and involves disorientation, lethargy, and nausea among other symptoms. It occurs when the body feels the need to acclimate while ascending. It’s a very dangerous condition that needs emergency care.
Here are some of the serious altitude sickness symptoms that mean immediate descent of the patient:
- Continuous and severe headache
- Persistent vomiting
- Ataxia (loss of sense, coordination, not able to walk in a straight line, drunk appearance)
- Loss of consciousness/ inability to stay awake or comprehend instructions
- Hallucinations
- Liquid sounds in the lungs
- Very persistent, sometimes watery, cough
- Breathlessness even at rest is rapid breathing
- Severe lethargy
- Face and lips turn blue
- Increased heartbeat rate (over 130 beats per minute)
- Mild symptoms are turning rapidly worse.
How do we treat a mild to worse symptom of Altitude Sickness?
When you become aware of mild symptoms while walking, first stop and relax. Get out of the sun and drink some fluids. It is crucial to stay hydrated. Take Diamox 125-250mg, which generally takes 1 to 4 hours to begin alleviating symptoms. Drink more water and consider staying close to fellow trekkers.
If the symptoms partially go away, but it's still annoying, it's considered safe to take another 250 mg of Diamox 6 to 8 hours after the first consumption.
When the mild symptoms continue to get worse, descending for a few hours may be more beneficial than staying at the same altitude for acclimatization. Going higher will definitely make it worse. So keep in mind that you trek to enjoy not to get sick.
If the symptoms are bad and you see signs of HAPE or HACE, you need to get medical help immediately after descent. You might also need to use extra oxygen if available. Your guide will have first aid training and will get all the possible help. However, you need to inform the guide immediately as soon as you start feeling any kind of discomfort so that you can prevent the condition from getting worse.
How do we prevent Acute Mountain Sickness / Altitude Sickness?
While altitude sickness can be challenging to estimate entirely, here are several measures that can significantly reduce the risk of experiencing altitude sickness symptoms:
1. Adequate time for acclimatization, after passing 3,000 m, allowing your body to adapt to the change in the environment
2. Slow and gradual ascent with occasional stops, allowing your body time to acclimatize. Consider the following recommended itineraries with built-in acclimatization dates.
3. Avoid alcohol, sleeping pills, and smoking which can further dehydrate and increase the risk of altitude sickness.
4. Drink more water, i.e., 3-4 liters per day. Best if it's clean boiled water or treated beverages like tea, coffee, soup, juice, etc.
5. Adequate nutrition, make sure you're eating a balanced diet to maintain your energy levels. Even if you have a loss of appetite, try to consume high-density foods that are easy to digest.
6. Avoid solo trekking or traveling, consider hiring a guide/porter so that it is easy to navigate the route and access to necessary help in unpredictable conditions or accidents.
7. Listen to your guide, hotel, locals, and guidebook
8. Immediate descent if mild symptoms rapidly get worse
9. Never leave or descend with a sick person.
10. Listen to your body
11. Keep yourself warm
12. Consider picking an easy and comfortable trekking route even if it's long.
13. Training and Pre-trek Preparation
14. Supplemental oxygen
15. Carry medications like acetazolamide, dexamethasone, or nifedipine. Consult a health care professional for recommendations, especially if you have a history of severe altitude sickness.
16. Reach out to professionals if the condition gets worse.
How to Prepare a First Aid Kit for Trekking Activities?
This list covers the more common ailments that afflict trekkers. A more comprehensive kit is necessary for climbing groups, expeditions, and trekkers going to remote areas. Carrying first aid is crucial for any trekking activities so that we can stop or minimize hazardous conditions from getting worse.
- Bandages for sprains
- Band-Aids/plasters
- Water filter (optional)
- Blister Band-Aid
- Antiseptic ointment for cuts
- Anti-bacterial throat lozenges
- Painkiller (Aspirin/Paracetamol)
- Antibiotics
- Diarrhea stopper
- Diamox 250 to 500 mg
- Sterile syringe set
- Hand sanitizer
Some Popular Myths and Misconceptions About Altitude Sickness that you should know
Altitude sickness is already quite a scary and hard experience when faced with in a real-life setting. However, some myths tend to worsen it and induce unnecessary fear into the minds of trekkers, which impacts them mentally and physically.
Some can't even comprehend the reality of it, and just spread false information. So here are some myths about altitude sickness debunked:
“Only unfit people are likely to get altitude sickness”
Which is false, because fitness has nothing to do with its prevention.
“Diamox cures altitude sickness completely”
No it doesn't. It helps prevent the symptoms but does not treat severe cases.
“Staying hydrated avoids getting caught by altitude sickness”
While hydration is necessary, it is not the ultimate solution as other strategies are essential too.
“Altitude sickness is endurable”
Absolutely not. The more you ignore the symptoms the worse it gets and might lead to life-threatening conditions.
“Drinking alcohol helps to sleep better at a higher altitude”
No it won't. Instead, it worsens altitude sickness symptoms.
A Practical Checklist for Trekkers
Before embarking on a high-altitude journey, carrying the right gear and proper planning can make a huge difference in preventing and managing altitude sickness. Here's a simple checklist that helps trekkers during trekking:
1. Acclimatization schedule: Include adequate rest days while planning your trek at key altitude points. Limit the altitude gain between 300 and 500 m in sleeping elevation per day above 3000 m, and take an acclimatization day after every 1,000 m gained.
2. Essential medications: Altitude sickness-related medications such as Diamox to speed acclimatization, Ibuprofen or Paracetamol for headaches, oral rehydration salts (ORS) to prevent dehydration, and prescribed drugs like Dexamethasone or Nifedipine, should be packed.
3. Travel insurance: It is always safe to have insurance that specifically covers helicopter evacuation and high-altitude trekking damages, since emergency rescues in mountain regions of Nepal can be expensive, i.e., USD $4000 to $6,000.
4. Hydration system: Make sure to have a reliable water supply system such as a CamelBak hydration Pack or sturdy water bottles. Also, pack water purification tablets or filters to have access to safe drinking water.
Final Words,
One of the main risks of high-altitude trekking is altitude sickness. To minimize this, we follow a gradual acclimatization process, remind trekkers to stay properly hydrated, and always emphasize listening to their own bodies. If symptoms begin to get worse, our priority is to descend to a safer, lower altitude. With the right preparation and precautions, reaching high-altitude destinations such as Everest Base Camp can be done safely.
At Ammonite Adventure, all of our guided treks to high-altitude like: Everest Base Camp are carefully planned with health and safety in mind. Our experienced leaders keep a close watch on every trekker’s condition and make necessary adjustments to the schedule whenever required. Get in touch with us today for expert guidance and to start planning your adventure to the Himalayas with confidence.
