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| Khardung La, Ladakh (in the background) is one of the busiest passes. At 17,582 ft (wrongly labelled 18,000 ft) is thought to be the highest motorable road |
What is AMS:
Acute mountain sickness (AMS), also known as Altitude sickness, is a negative health effect of high altitude, caused by acute exposure to low amounts of oxygen at high altitudes. It presents as a collection of nonspecific symptoms, acquired at high altitude or in low air pressure, resembling a case of "flu, carbon monoxide poisoning, or a hangover. (Wikipedia)
Causes
The concentration of oxygen at sea level is about 21% and a pressure averages 750 mmHg. As we move higher, the percentage of oxygen remains unchanged but the amount of oxygen per breath is reduced.
At 12,000 ft (3,658 m) the pressure is only 480 mmHg, so there are roughly 40% fewer oxygen molecules per breath. In order to keep up with the oxygen requirement of the body, your breathing rate has to increase, even while doing nothing. However, the body cannot keep up with the oxygen demand since our oxygen requirement is the same at all altitudes. In addition, for reasons not entirely understood, high altitude and lower atmospheric pressure cause fluid to leak from the capillaries which can cause fluid build-up in both the lungs and the brain. Continuing to higher altitudes without proper acclimatization can lead to potentially serious, even life-threatening illnesses.
Symptoms
The most common and first symptom is a headache. The intensity of a headache may vary.
This is usually accompanied by
nausea,
breathlessness,
dizziness,
loss of appetite
disturbed sleep
fatigue and
a general feeling of malaise
Also, note that statistically, 75% of us get mild sickness above 10,000 ft. Generally, these symptoms do not interfere with normal activity and subside within 48 hours. Symptoms do get worse at night when breathing is slower.
Who gets it?
Absolutely anyone. Regardless of age, sex, fitness levels and even those who haven’t been affected on earlier visits to high altitudes. So utmost caution should be taken by everyone.
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| En route to Polokongka La (~16000ft) |
Acclimatization
The major cause of altitude illnesses is going too high too fast. Given time, your body can adapt to the decrease in oxygen molecules at a specific altitude.
The ideal way to acclimatization is not to fly directly to high altitude, however, if you are to spend at least 24 hrs at 10,000 ft without excreting yourself at all (not even short strolls).
After which you will need to take it easy, do not run or overexert yourself during the entire trip.
DO NOT ignore symptoms and keep your group leader or local contact informed.
Try keeping the stay at the highest location at the end of the trip. Plan your trip to gradually increase in altitude.
If you get continued symptoms or if the symptoms grow, stay at a lower altitude until the symptoms go. If they persist consult the local doctor if available or just travel immediately to a lower altitude.
Hydration: Acclimatization is often accompanied by fluid loss, so you need to drink lots of fluids to remain properly hydrated (at least 3-4 quarts per day). Urine output should be copious and clear drink a sufficient amount of water.
Food: Do not skip meals, since due to AMS you lose your appetite, however you would need to fuel your body especially if you are on a trek. Eat a high carbohydrate diet (more than 50-70% of your calories from carbohydrates) while at altitude.
Sleep: Avoid sleeping during the day (resting is fine), since when you sleep the body slows down all processes including breathing, which causes the symptoms to increase.
others: Avoid tobacco and alcohol and other depressant drugs including, barbiturates, tranquillizers, and sleeping pills. These depressants further decrease the respiratory drive during sleep resulting in a worsening of the symptoms.
Preventive medicine
[DO NOT use Diamox without consulting your doctor.]
Diamox (Acetazolamide) allows you to breathe faster so that you metabolize more oxygen, thereby minimizing the symptoms caused by poor oxygenation. Diamox is the accepted medicine as of now.
However, check for allergies to Sulpher.
If you are on Diamox, drink lots of water to avoid dehydration, since Diamox is a diuretic.
Possible side effects include tingling of the lips and fingertips, blurring of vision, and alteration of taste. Since Diamox is a sulfonamide drug, people who are allergic to sulfa drugs should not take Diamox. Diamox has also been known to cause severe allergic reactions to people with no previous history of Diamox or sulfa allergies. (Curtis, 1998).
I DO NOT recommend any medication to be taken without consulting a proper doctor, preferably one who is aware of your medical history.
Other Local remedies
Carry Camphor with you, it sometimes helps with some of the symptoms like nausea and dizziness, but note that it is not a cure.
Trekking
AMS is usually not a problem for easy to medium grade treks, like treks in the lower Himalayas (up to 12000 ft) Since you gain altitude as you travel higher and acclimatize well. However, if you are starting your trek at a higher altitude. it is recommended to acclimatize at least for a couple of days (2-3 days) at base altitude.
Acute mountain sickness (AMS)
Whatever we discussed till now can also be described as mild AMS. Anything more than mild AMS can be life-threatening. In case of severe acute mountain sickness, the only way out is to travel to a lower altitude.
Disclaimer: This article is for birders, wildlife enthusiasts and tourists travelling to high-altitude places for leisure or light to medium hikes. This article is not for mountaineers and extreme trekkers (over 18,000 ft), since my experience with the same is limited. If you are on a mountaineering expedition I suggest treating this article as an initial read, you will have to read more about AMS in relation to mountaineering.
References:
Altitude information for travellers ascending beyond 3000 meters by Rick Curtis, Outdoor Action Program, Princeton University [1998]
DO NOT ignore symptoms and keep your group leader or local contact informed.
Try keeping the stay at the highest location at the end of the trip. Plan your trip to gradually increase in altitude.
If you get continued symptoms or if the symptoms grow, stay at a lower altitude until the symptoms go. If they persist consult the local doctor if available or just travel immediately to a lower altitude.
Hydration: Acclimatization is often accompanied by fluid loss, so you need to drink lots of fluids to remain properly hydrated (at least 3-4 quarts per day). Urine output should be copious and clear drink a sufficient amount of water.
Food: Do not skip meals, since due to AMS you lose your appetite, however you would need to fuel your body especially if you are on a trek. Eat a high carbohydrate diet (more than 50-70% of your calories from carbohydrates) while at altitude.
Sleep: Avoid sleeping during the day (resting is fine), since when you sleep the body slows down all processes including breathing, which causes the symptoms to increase.
others: Avoid tobacco and alcohol and other depressant drugs including, barbiturates, tranquillizers, and sleeping pills. These depressants further decrease the respiratory drive during sleep resulting in a worsening of the symptoms.
Preventive medicine
[DO NOT use Diamox without consulting your doctor.]
Diamox (Acetazolamide) allows you to breathe faster so that you metabolize more oxygen, thereby minimizing the symptoms caused by poor oxygenation. Diamox is the accepted medicine as of now.
However, check for allergies to Sulpher.
If you are on Diamox, drink lots of water to avoid dehydration, since Diamox is a diuretic.
Possible side effects include tingling of the lips and fingertips, blurring of vision, and alteration of taste. Since Diamox is a sulfonamide drug, people who are allergic to sulfa drugs should not take Diamox. Diamox has also been known to cause severe allergic reactions to people with no previous history of Diamox or sulfa allergies. (Curtis, 1998).
I DO NOT recommend any medication to be taken without consulting a proper doctor, preferably one who is aware of your medical history.
Other Local remedies
Carry Camphor with you, it sometimes helps with some of the symptoms like nausea and dizziness, but note that it is not a cure.
 |
| Valley of Flowers Trek, Uttarakhand |
Trekking
AMS is usually not a problem for easy to medium grade treks, like treks in the lower Himalayas (up to 12000 ft) Since you gain altitude as you travel higher and acclimatize well. However, if you are starting your trek at a higher altitude. it is recommended to acclimatize at least for a couple of days (2-3 days) at base altitude.
Acute mountain sickness (AMS)
Whatever we discussed till now can also be described as mild AMS. Anything more than mild AMS can be life-threatening. In case of severe acute mountain sickness, the only way out is to travel to a lower altitude.
Disclaimer: This article is for birders, wildlife enthusiasts and tourists travelling to high-altitude places for leisure or light to medium hikes. This article is not for mountaineers and extreme trekkers (over 18,000 ft), since my experience with the same is limited. If you are on a mountaineering expedition I suggest treating this article as an initial read, you will have to read more about AMS in relation to mountaineering.
References:
Altitude information for travellers ascending beyond 3000 meters by Rick Curtis, Outdoor Action Program, Princeton University [1998]
Wikipedia: https://en.wikipedia.org/wiki/Altitude_sickness#cite_note-1
Very well written Asif.
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