What is altitude sickness

Altitude sickness is negative body reaction to high altitude environment, specifically to lower amounts of oxygen and air pressure. Common symptoms are headache, insomnia, reduced strength and stamina, inapetence, dizziness, fatigue and sometimes vomiting.

In extreme cases, the person might develop acute mountain sickness (AMS) which progress to high altitude pulmonary edema (HAPE) or high altitude cerebral edema (HACE). These conditions are life threatening and requires immediate descend to lower altitude and medical attention.

In what elevation and places you should be worried

Luckily, the altitude sickness is rarely affecting anyone in the elevations below 3500 meters and acute mountain sickness basically only happens in the altitudes above 4000 meters.

All the towns in Bhutan are located in elevations below the 3000 meters where only very sensitive people might notice shortness of breath or slight headaches. These symptoms will usually disappear in a few days. Most of the people are not affected at all.

Even if you are coming from the sea-level directly to Bhutan, you will be just OK. Paro airport is in the 2200 meters, which is totally innocuous elevation. If you heard stories about people collapsing with altitude sickness right after their arrival to Himalayas, the talk wasn’t about Bhutan but Leh in Ladakh (3500 m) or Lhasa in Tibet (3650 m).

On cultural tour, you don’t need to be worried with altitude at all. However if you are heading for trekking, you should take some precautions.

Ascending to the Nyile-la pass, here the acclimatization on Snowman trek is first tested

Prevention of altitude sickness: acclimatization

The most important thing to remember about altitude sickness prevention is to ascend to higher elevations slowly. Most of the people will be affected by some short breath and other symptoms above 3000 meters, anyway just having headache and bad sleep is not a reason to worry, this will disappear shortly as you acclimatize.

In the ideal trekking itinerary the first night after arrival to Bhutan should be held in moderate elevation below 2500 meters like in Paro or Thimphu.

The first trekking overnight should be around 3000 meters, where you might start feeling the mild effects like shortness of breath during hiking or light headache.

The next night might be around 3500 meters, where almost everyone will feel some light symptoms. Ideally, you should spend two nights in this elevation, however this is not always practically possible.

The following campsite would be around 4000 meters and two nights stay should be observed to be on the safe side. On the rest day, you should undertake up-and-down hike to higher altitude, at least to 4500 meters or above. This will prove if your body is getting acclimatized to higher elevations. If you are suffering with serious shortness of breath while hiking, having a bad sleep, headache and no taste for food, this is certain sign, that you should not proceed farther. However, if you are feeling perfectly good  or at least quite good after the two nights halt in around 4000 meters, you are fully acclimatized to go above 4500 meters and you would probably not face any further issues on the trek.

Altitude sickness is not developing during the day but usually it starts overnight, so crossing the high pass above 5000 meters will not affect your acclimatization, only the elevation where you sleep matters. Vast majority of campsites on Bhutanese trekking trails are not located above 4500 meters so once you gain acclimatization for 4000 meters, you should be OK for the whole trek.

Anyway you should mind that every trek requires different acclimatization approach, depending on topography and practicality. All trekking itineraries promoted by Firefox Tours are planned with safe acclimatization in mind. While we can’t rule out the occurrence of altitude sickness completely, our acclimatization programs are solid enough to prevent problem in vast majority of cases.

Dos and Don’ts during acclimatization

There are important precautions to follow during the acclimatization phase:

• Alcoholic drinks should be avoided, as it undermines the acclimatization.
• If you are suffering with any kind of respiratory infection, even just running nose or mild cold, you should consider to postpone the start of the trek, since it will certainly get worse with altitude and it will hamper the proper acclimatization process.
• You can help your body with acclimatization if you eat lot of the garlic, the favorite mountaineering staple. Taking additional vitamins C and E will certainly boost your power too.
• Resting a lot, after the completions of the day’s hike, is also the key. Don’t do additional exercises in the free time, give your body a peace to adjust to changing environment.
• When walking, go rather slowly and steadily. Going fast and stopping frequently to catch a breath is exhausting you silently but resolutely. Your body will not be able to acclimatize if you wear out yourself.
• Breathe deeply and steadily, even if you are just resting. Making series of deep breath-ins and breath-outs will refresh you and give you extra power in case you feel dizzy.

Most importantly, you should always be honest with yourself, your companions and trekking staff. If you feel unwell, don’t hide it. By playing hero, you might actually put others in trouble. Most cases of life threatening acute mountain sickness actually happens when people do previously ignore or conceal the milder symptoms. Don’t be like that and prevent real problem from happening!

Reading the measurements from pulse oximeter is quite simple

Using pulse oximeter to measure acclimatization

Handy medical device called pulse oximeter can be helpful to ascertain if you are suffering from altitude sickness. This small battery powered finger-clip instantly measures percentual oxygen saturation (SpO₂) in your blood. Insufficient saturation along with other symptoms indicates altitude sickness.

However the normal oxygen saturation decreases with altitude. For that you need to follow reference table below and always compare the measured SpO₂ with current elevation.

If your measurement is lower than 5 percent points below the indicated normal levels of SpO₂ for given altitude and at the same time, you suffer with with some of the typical symptoms described above, you should not hesitate and start descending to safe altitude.

If you have only mild symptoms, you might consider to wait extra day in same altitude to get better acclimatized.

However, if you feel perfectly and absolutely well, you don’t need to get bothered even if your SpO₂ is much below the normal level. Only the low levels of SpO₂ along with other symptoms do indicate sickness.

When measuring yourself with oximeter, do follow this steps:

• Measure yourself on each evening and morning. That will give you idea how your personal oxygen saturation compares to normal one as per reference table and how it decreases with the altitude.
• Make sure to have a spare batteries of good quality
• Before taking measurements, keep oximeter in pocket for some time to make it warm
• Also your hands should not be freezing when taking oximeter reading

Along with SpO₂ oximeters also measures heart rate (PRbpm) and somemites also Perfusion Index (PI%). These values are not relevant to high altitude and you can ignore that.

Firefox Tours do equip it’s trekking groups with oximeters or you can easily purchase one in electronic or medical equipment shops or pharmacies.

Taking Acetazolamide to prevent altitude sickness

Acetazolamide (sold as Diamox, Diacarb or Diuretan etc.) is widely available drug to prevent and treat high altitude sickness and some other ailments.

Usual recommendation for preventive use is to take one 250 mg tablet once a day in three dosages, starting two days before reaching altitude of about 3500 meters.

There are other dosage scenarios discussed and recommended by another studies like taking 125 mg twice daily or even 250 mg twice daily. You can consult your physician or decide on your own.

Acetazolamide is safe drug unless you are pregnant or allergic. Some people reports that drinks and food tastes dull on tongue after taking the pills.

Please remember that this drug will only decrease the chances of suffering with altitude sickness, it is not substitute for proper acclimatization. Also preventive effects are still not conclusively confirmed by science, although solid evidence supports it.

Acetazolamide is not available without prescription in most developed countries. In Nepal and India, it can be purchased freely though. In Bhutan, Acetazolamide is not easily available so if you want to take it, you should bring it from abroad.

photo courtesy of RBHSL

Helicopter might be the only rescue option in case you get high altitude sickness

What to do if you are affected by acute mountain sickness

There are three main things you have to do in case you are affected by severe altitude sickness: descend, descend, descend!

Even the very serious condition gets quickly better in low altitude. On the other hand, while staying in high altitude, the sickness only progress further to serious hypoxia (lack of oxygen), coma and death.

There are not many things which can be done to help sick person while staying in high altitude. Taking Acetazolamide for AMS treatment will help a little but definitely not enough.

Laying a person to gamow bag, the pressurized mini-tent which simulates altitude about 500 to 700 meters lower offers some relief before the rescue can be conducted. Unfortunately gamow bags are not normally being carried by trekking groups in Bhutan and aren't even available in the Basic Healthcare Units (BHUs) in the villages along the way.

Supplement oxygen is another partly effective aid. Unfortunately pressurized oxygen bottles can't be carried in sufficient amounts by trekking groups, but are usually available in the BHUs. These might be too far though.

Calling helicopter is usually the best way how to quickly rescue the sick person. Anyway in case of the bad weather (which can lasts for several days) the air-rescue might not be immediately possible. In such case, carrying the sick person on horse or stretcher might be the only available option with huge hardship for all involved.

For that reason, the slow and steady acclimatization is the must, since there is no good solution when the acute mountain sickness develops. Simply the best aid is the prevention.

So always be careful, responsible and safe!