Altitude sickness, also called Acute Mountain Sickness (AMS), is something all people who venture above 2,500m need to know about.
In this article we have asked high altitude trekking specialist, Mark Whitman, to share his top tips for adventure seekers.
1. Understand Acclimatization
Acclimatization is your body’s way of coping with lower oxygen levels at higher altitudes.
When going to high altitude (i.e. greater than 2500m), it is really important that you give your body time to acclimatize.
On a physiological level, you will start to adapt to higher altitudes by accelerating your breathing and by breathing deeper. Your blood concentration will change, and blood will start moving into areas of your lungs not used at lower altitudes. You can take an ankle brachial index test before your trip to see if it’s safe for you to trek in these conditions. The test compares the blood pressure in your arm to your legs, significantly higher blood pressure in the lower extremities could mean narrowing of the arteries in that area. This can lead to pain, aches, or cramps while doing physical activities. You can read more on it here.
An enzyme will also be secreted into your body that allows for a more effective transfer of oxygen from hemoglobin to your blood tissues. These changes allow you to cope with the lower levels of oxygen at higher altitudes.
The term ‘Acclimatization Line’ came about to explain a person’s point at which they start to experience issues with altitude sickness. As you move higher in altitude, your acclimatization line moves higher. It is important that you note your acclimatization line and make sure you get below it if you start to experience AMS symptoms. Resting at your acclimatization line for a day or so will usually resolve symptoms and you can then keep going higher.
2. Walk High, Sleep Low
A good idea to help prevent altitude sickness is to hike high, but sleep low. This means you sleep at a lower elevation to which you hiked during the day.
For example. If you are at about 3,000m, and you ascend about 700m during the day to reach 3,700m, try to find a location lower than that at about 3,500m to sleep. This is a good way to help your body acclimatize and prevent any symptoms of altitude sickness.
Research suggests that one should not sleep higher than 500m per day.
3. Don’t overexert yourself, Go Slowly
Giving your body enough time to acclimatize is of utmost importance to prevent AMS. Don’t try to trek at high altitudes as fast as you can, this will only wear you out and increase your risk of altitude sickness.
Ascend slowly and you will have much more chance of reaching your highest destination without any altitude sickness symptoms.
Also, don’t rush your hike. Take your time and don’t overexert your body that is already trying to cope with the lower oxygen levels.
For example, on Kilimanjaro, the highest mountain in Africa, guides and porters are known for saying Pole, Pole, a Swahili word which means ‘slowly, slowly’. They know the importance of taking your time to ascend Kilimanjaro.
4. Recognize symptoms quickly
Symptoms include three levels, mild, moderate and severe.
Mild symptoms usually present within the first 12 – 24 hours at a certain altitude.
- Loss of appetite
- Shortened breathe
- Disturbed sleep
Moderate symptoms include:
- Nausea leading to vomiting
- Extreme fatigue
- Ataxia (feeling decreased coordination)
Severe altitude sickness is very scary and can be life-threatening.
Severe symptoms include:
- Severe breathing trouble
- Fluid buildup in the lungs or HAPE (High Altitude Pulmonary Oedema) inhibits the transfer of oxygen into your blood. It is fatal and descending is of paramount importance! If you are feeling a tight chest, having trouble breathing, coughing up mucus, experiencing hallucinations and irrational behavior – you could very likely be suffering from HAPE.
- An inability to walk
- HACE (High Altitude Cerebral Oedema) is when the pressure in the brain increases to a point where fluid builds up in the cranium. It tends to strike at night and gets worse very fast. Intense migraines, confusion, and disorientation or even loss of consciousness are symptoms of HACE. Do not take any chances with this – descend immediately and seek medical attention!
If you are experiencing these symptoms, make your way immediately to a lower altitude. You will not alleviate these symptoms otherwise. Most likely you will feel better after some time spent at the lower altitude and you can then continue your hike.
5. Avoid alcohol and smoking, but maybe take Diamox
Alcohol is said to increase the effects of altitude sickness and can cause symptoms similar to altitude sickness. It can also affect your breathing as it relaxes the bodily functions.
Smokers on the other hand initially might find their acclimatization line is higher than non-smokers, as they are used to shallower breathing but in the long run, they can run into issues.
Smoking typically decreases your breathing ability and compromises your blood flow. If you are hiking in cold climates, frost-bite will probably be more of a risk for smokers due to bad blood pressure in their hands and feet. Long term smokers usually have lower lung capacity than non-smokers which can increase altitude sickness symptoms.
An interesting discovery is that caffeine is believed to help with symptoms of altitude sickness. Previously, it was considered a no-no. But caffeine is a known stimulant that is helpful for breathing at high altitudes and can support kidney and brain activity.
Diamox is a medication that is used to prevent altitude sickness. It is not a cure – so please do not think taking it will solve your symptoms. The drug comes with its own side effects such as; frequent urination, tingling sensations on your fingers or toes, changes in your taste, as well as nausea. These effects can be similar to altitude sickness. Make sure to test the drug before you go to high altitude to see if you experience side effects. It can be obtained over the counter in some areas, but please consult with your doctor first.
6. Descend if AMS symptoms worsen
It is highly important to descend to a lower altitude immediately if your altitude sickness symptoms worsen. If you do this in time, your body can regulate and bring itself to a point where it can cope with the lower oxygen levels.
This is extremely important if you are experiencing severe symptoms. You will not alleviate the symptoms by waiting it out, they will only worsen. Altitude sickness can be fatal.. Please attend to anyone experiencing such symptoms immediately and get them down fast!
7. Know your levels of altitude
There are three main levels. High, Very High and Extreme altitude.
High altitude refers to the zone between 2,500m and 3,500m. A good example is the hike to the famous Inca ruins of Machu Picchu.
Very High Altitude refers to the zone between 3,500m and 5,500m. An example of this is the hike to Everest Base Camp in the Himalayas.
Extreme Altitude refers to altitudes above 5,500m where you are highly at risk for AMS. Following the previous example, a trek to the peak of Mount Everest at 8,848m high is an example of extreme altitude.
Knowing your altitude, being educated on how this affects your hike or climb, will help you to understand when and where to not push your body.
AMS can put a real damper on your journey. Don’t take risks and listen to your body.
If you follow the guidelines and educate yourself on altitude sickness, the risks and symptoms, you will be well on your way to preparing for great adventures at high altitude!