Monday, January 21, 2013

What is a Sherpa?

We should begin by understanding that "Sherpa" is not a job description. It is a people. About 153,000 Sherpa live in Nepal today. Their ancestors came to this region by way of Tibet and, prior to that, regions still further east. It is believed they followed well established salt trading routes.The term Sherpa translates in Tibetan as "Shar" eastern"pa" peopleOriginally a nomadic people, the Sherpa transitioned to agriculture and livestock farming after arriving in Nepal in the 1500's

Most of us would never have heard of the Sherpa people were it not for their invaluable contribution to climbing endeavors in the Himalayas. Sherpa men were hired by early expeditions as Guides. Their keen knowledge of the complex valleys and peaks of the Himalayas proved essential to the first Climbers, Explorers and Cartographers to venture into the region. Soon the Sherpa were likewise recognized for their extraordinary ability to function at high altitudes and expeditions began hiring them in great numbers to carry supplies. This practice continues today as Everest expeditions benefit greatly from the remarkable load-packing ability of the Sherpa. International Mountain Guides, the company I am climbing with, will hire something on the order of 60 Sherpas this season.

Myself, Richard, Ang, and Brian
I climbed Kilimanjaro in January of 2008 with Adventure Consultants of New Zealand. We were led by one of their Everest Guides, a Sherpa named Ang Dorjee. Aside from his incredible 16 summits of Everest, Ang is famous for being featured in the bestseller Into Thin Air. He is one of the Hero's who survived, and helped others survive, the tragic events of May 10, 1996 when 8 climbers perished. This link will take you to a short You Tube video of Ang preparing us before our summit bid of Kilimanjaro Click here to see Ang  
As Richard, Brian and myself marched up the mountain in full battle gear, Ang calmly walked beside us, hands in pockets, wearing tennis shoes. He never seemed cold, or tired, or out of breath ...even at 19,000 feet. Ang's resting blood-oxygen level measured a robust 98 at high camp, while the rest of us logged numbers that could start a shoving match between funeral directors.  

Dr. Kenneth Kamler, in his excellent book Surviving The Extremes: A Doctors Journey to the Limits of Human Endurance, discusses the physiological adaptations of humans to high altitude. Sherpas are specifically addressed in one part of his book. Dr. Kamler identifies several fascinating differences between Sherpas and us mere mortals scrubbling around at sea level. 
1. Sherpa lungs have a high idling speed. Which is to say they have a high sensitivity to low oxygen environments and will maintain an increased rate of breathing, even at rest. Most climbers take a drug called Diamox to accomplish this. 
2. A Sherpa's heart muscle can take in glucose. Glucose burns 50% more efficiently than fat (the fuel used by a typical heart) in a low oxygen environment. The net result is the same cardiac output with much less work. 
3. Sherpa blood has something extra. The capacity of a Sherpa's blood to transport oxygen is greatly increased by special enzymes that ride along with the hemoglobin to speed up the capture and release of oxygen. 
4. Sherpas lungs produce more vasodilators. Sherpa lungs produce twice the nitric oxide as almost everyone else. Nitric oxide acts as a vasodilator, opening up constricted vessels in the lungs. This may be why Sherpas are virtually immune to pulmonary edema.
5. Sherpas produce less lactic acid. Sherpas working at maximum capacity produce less lactic acid than the rest of us, a condition known as the lactic acid paradox.  The probable explanation is that Sherpas don't need to form lactic acid because they can maintain high fuel-burning efficiency, even in low oxygen by using enzymes we still have not identified. 

All of this combines to make the Sherpa people, and thus the Sherpa climber, extraordinary human beings when it comes to functioning at high altitude. So much so that the term Sherpa has been borrowed for many other uses descriptive of these qualities. In photography, the person who carries the equipment is known as a "Sherpa". The Short SB.4 Sherpa aircraft was designed and built in 1950 to test capabilities for very high altitude flight. Again and again, when we seek superlatives to attach to things which carry outsized loads or operate in rarefied air the term Sherpa is used. 

Approximately 93% of Sherpa are Tibetan Buddhists. Their oral history suggests that their initial migration from Tibet to Nepal was a search for Shangri-La. Being Guru Rinpoche Buddhists, the Sherpa believe in hidden valleys and treasures. But other evidence supports the notion that religious conflicts with the Chinese prompted their westward movement. 

The most well known Sherpa is Tenzing Norgay. In 1953 he and Sir Edmund Hillary became the first people known to have reached the summit of Mt Everest. There have been female Sherpa climbers, though tragedy has haunted them. Pasang Lhamu Sherpa was the first Nepali female climber to reach the summit of Everest, however she died during the descent. The great female Sherpa Pemba Doma Sherpa summited Everest two times before she died in a fall from Lhotse on May 22, 2007.

Today there are about 5,000 Sherpa living in the United States. Half of these are in the peaceful hamlet of New York City. Go figure. The remainder are scattered among the states. My friend Ang Dorjee is one of them. He married a scientist he met while she was studying climate change at Everest base camp. Today they live with their two children in Richland, Washington.