Category Archives: Altitude Sickness

Lessons on Altitude Sickness from the Himalayan Rescue Association

Annapurna Base Camp, at over 15,000 feet

A group of us trekker are sitting in a circle in a health clinic in the town of Manang, which sits at elevation of 11,500 feet in the Nepal Himalayas. A few look drawn and tired; a young woman is complaining of headaches. Outside, a group of porters walks by, one with his head wrapped in a towel soaked in cold water. He insists he is okay.

What we are learning here, at this class for trekkers given by the Himalayan Rescue Association, may tell us otherwise.

The Himalayan Rescue Association was founded in 1973 as a collaboration among volunteer visiting doctors, Nepali health officials and doctors, and representatives from trekking companies. The founders recognized that Nepal’s trekking routes were drawing more and more tourists to the high altitudes of the Himalayas – but at a cost.

The most common trekking routes reach dangerous altitudes for inexperienced hikers: up to nearly 18,000 feet at Everest Base Camp and at the Thorong La on the Annapurna Circuit, and more than 16,000 feet on other popular routes. The first foreign visitors to these high mountains were skilled outsdoorspeople with experience at altitude. But as trekking became more and more popular among “lay people,” it became clear that many trekkers had no idea how to recognize and respond to the symptoms of altitude sickness. Some became seriously ill. Some died.

Mt Everest and Annapurna Himalayan Rescue Association Aid Stations

The first aid  station was opened in 1973 at the hill town of Pheriche in the Khumbu region, on Nepal’s Mt. Everest Trek, at an altitude of about 14,000 feet. During the trekking seasons, it was manned by volunteers who lived in yak herders’ huts and tents.

A second station was opened in 1981, in Manang, a town on the Annapurna Trek, a two-day walk from Thorong La, the 17,800-foot pass that is the Annapurna Trek’s highest point. In 2008, another aid station was opened at Thorong Phedi — the foot of Thorong La, the pass that is most dangerous on the Annapurna Circuit. At these aid stations, doctors provide education, screening, and treatment; if necessary, they also aid in rescues of afflicted trekkers.

Educating Nepal’s Trekkers About Altitude Sickness

Nepal’s High altitudes can be dangerous.

Where altitude sickness (also called acute mountain sickness) is concerned, prevention is always the best course of action. This is particularly true in Nepal, where rescue is difficult because there are no roads into the trekking areas. Air-rescue is expensive and often impossible because of weather conditions and terrain.

So the Himalayan Rescue Association program focuses on prevention. They publish a series of educational pamphlets, available in Kathmandu hotels and trekking agencies. And during the trekking season, doctors hold a daily lecture on altitude sickness at the hill-town aid stations. By screening trekkers as they come through the high hill towns, the Himalayan Rescue Association has been able to decrease the incidents of mountain sickness.

The lectures teach trekkers to recognize symptoms of altitude sickness, and stress the importance of gaining elevation slowly and taking rest days. This advice is particularly important on the Annapurna Trek, because the Thorong La reaches such high elevations, and on the Everest Trek, because today, many Everest trekkers fly to the airstrip at the high-altitude village of Lukla. They therefore forego some of the essential acclimatization that is one of the main ways to prevent altitude sickness.

Himalayan Rescue Association doctors also stress that Nepali porters and guides are also susceptible to altitude sickness. While many Sherpa people native to the Sol Khumbu region near Mt. Everest are well-acclimated to the high altitude, porters and guides from lower elevations near Pokhara or Kathmandu are often just as susceptible to altitude sickness as trekkers – but may be less likely to admit to it, since their jobs depend on their strength. Trekkers therefore, need to be alert not only to their symptoms, and those of their trekking partners, but to symptoms of porters and guides as well.

Volunteer Doctors and the Local Communities

In addition to providing preventative care for trekkers, guides, and porters, the Himalayan Rescue Association has done comprehensive research on the subject of altitude sickness. It also provides free and low-cost medical care to local villagers who live near the stations (sometimes, the staff even tries to treat sick animals brought in by villagers!). These are remote towns, far from any roads, and the health care provided by the volunteer doctors is the only western medical care available. Donations collected from trekkers are used to support the medical care given to local people.

Altitude Sickness: A Basic Primer for High-Elevation Mountain Hiking

Summer is the best time of year for tackling high trails in high mountains. In June, snow starts melting, in July, trails are mostly passable, in August, mosquitoes are less of a problem. But one issue can rear its head — and potentially knock you off yours: Altitude sickness.
Also called Acute Mountain Sickness (AMS), altitude sickness is a risk on alpine adventures, particularly for people who live at low elevations.. It is easily prevented by acclimating and responding to early symptoms.

Altitude sickness is caused by the fact that the higher the elevation, the lower the air pressure; hence, the less oxygen you take in with every breath. Early symptoms include shortness of breath, even when only lightly exerting, as well as headaches and nausea. Ignoring these symptoms or continuing despite them can lead to more symptoms — dizziness, confusion, lack of coordination, and staggering — followed by full-blown AMS.  In the late stages, potentially fatal pulmonary and cerebral edemas can occur.

Danger Zones for Altitude Sickness

Hikers and climbers on adventure travel trips frequently ascend high above sea level. Examples of popular high altitude treks include trekking the Inca Trail in Peru, climbing any of East Africa’s volcanoes, trekking in Nepal and Bhutan, glacier skiing in Europe, hiking in much of Colorado, California, and Wyoming, and climbing the Pacific Northwest and Mexican volcanoes. It is also a possibility when ascending via car, train, or even ski lift.

Symptoms of Altitude Sickness

The first rule of high elevations is to “Blame it on the altitude.” This means that travelers to alpine areas above 8,000 feet should assume any maladies or irregularities they are experiencing are due to altitude. If something is wrong up high, don’t pass it off as “allergies,” “jetlag,.” or”something you ate.” It’s probably altitude related, and if it is, it needs to be dealt with.

Common early symptoms of altitude sickness are headaches and nausea. These are warnings that the body is not getting enough oxygen. With mild symptoms, sometimes all that is needed is a rest day, which gives the body a chance to acclimate. Most people can acclimate to the kinds of elevations common on alpine adventure travel vacations (10,000 to 16,000 feet; sometimes more) if given enough time. In fact, time to acclimate is the number one way to prevent altitude sickness -– and lack of time to acclimate is the number one cause of it.

Often,  simply taking a rest day is enough to solve the problem. The body adjusts and the traveler moves onwards and upwards. But if symptoms persist or increase, afflicted travelers should go downhill until they feel better.

Who is at Risk of Altitude Sickness?

The short answer is that anyone can be at risk, even people who have successfully climbed to high elevations in the past. People who live at sea level are especially vulnerable when they change altitudes too quickly, for example, when flying from sea level to a high-altitude town or ski area. In addition, people who are elderly, frail, chronically ill, or who have breathing problems are especially at risk.

It is impossible to say at precisely what elevation a trekker may feel the effects of altitude. Many factors influence travelers’ responses to altitude, including overall fitness, the length of time travelers have been at altitude, whether the travelers are adequately hydrated, and how slowly (or quickly) they have been ascending. Further confusing the picture is the fact that the same hiker may do the exact same trip twice in a row – and might respond differently each time.

The Continental Divide Trail in Colorado averages more than 11,000 feet.

Many travelers who live at sea-level feel some shortness of breath at higher elevation ski areas (around 8,000 feet), such as those in Colorado or the Alps, or while driving scenic mountain roads over high passes. Most healthy adults adjust easily to altitudes of less than 10,000 feet, although it may take a few days to get up to full speed.

Minimizing the Risk of Altitude Sickness

Above 10,000 feet, the standard recommendation is that trekkers try to gain no more than 1,000 feet of net elevation per day. Following the mountaineer’s dictum of “Climb high, sleep low,” climbers often hiker higher during the day, which helps acclimatization, then return lower to sleep.  If you fly to a high altitude town from which you plan to start your trek, take a couple of rest days to get used to the elevation. This is not always possible, in which case, take rest days en route. Time is the most effective defense against altitude sickness: It allows the body to catch up with the altitude.

The second most important defense is adequate hydration: “A happy mountaineer pees clear.” Drink even when not thirsty; in cold dry weather, hikers are often unaware of incipient dehydration

Finally, there are medical drugs. If time is a problem (as it often is on guided adventure trips), talk to a doctor about the drug Diamox, which is used as a prophylactic. Be aware that it is a preventative, not a treatment: It must be taken before any symptoms arise.

With adequate planning, plenty of time and water, and an understanding of the symptoms and danger of AMS, altitude sickness is easily preventable.