Supermen Living in Nepal
There is a race of people at the base of Mt. Everest capable of feats that defy scientific explanation: the Sherpas. They can carry up to twice their body weight under three hostile conditions that would wear out most of us in a minute: (1) high altitude, (2) long distance, and (3) steep inclines. Somehow, the techniques they use and the adaptations their bodies have made from living in that environment have made them the supreme load carriers of the human world (they even beat out African women who routinely carry heavy loads on top of their head). This was the subject of a research paper in Science this week.1 Science Now sums it up:
When the going gets tough, the tough use their heads. Porters around the world carry loads that would floor backpackers by balancing baskets atop their noggins or slinging sacks from their craniums. Now a new study reveals that Nepalese porters do the job better than anyone else, hefting huge bundles while using relatively little energy. (Emphasis added in all quotes.)
The study, also reported by National Geographic News, found that Nepalese porters or sherpas routinely carry double what backpackers carry, under more extreme conditions, yet burn less energy:
The town of Namche (at an altitude of 3500 m [11,400 ft]) near Mount Everest hosts a weekly bazaar. Porters (Fig. 1A), predominantly ethnic Rai, Sherpa, or Tamang, typically take 7 to 9 days to travel to Namche from the Kathmandu valley. The route, no more than a dirt footpath, covers a horizontal distance of 100 km, with total ascents (river crossings to mountain passes) of 8000 m [5 vertical miles] and total descents of 6300 m [4 vertical miles].
One day before the bazaar, we counted 545 male and 97 female porters (and 32 yaks) en route to Namche; others passed by earlier and later in the darkness. We weighed randomly selected porters and their loads. The men carried loads of 93 +- 36% of their Mb (mean +- SD, n = 96 male porters), whereas the women carried 66 +- 21% of their Mb (n = 17 female porters). The youngest porter was 11 years old, and the oldest 68; the greatest load measured was 183% of Mb, and 20% of the men carried > 125% of their Mb. More than 30 tons of material were ported to Namche that day.
The researchers measured their oxygen intake and carbon dioxide output under controlled conditions, and found that their energy utilization was “far more economical than the control subjects at all loads and more economical than the African women at all except the lightest loads.” They marveled at watching them in their normal business hauling loads around the mountains. How they do it is a mystery:
The load versus speed versus energy-cost trade-off chosen by these porters is to walk slowly for many hours each day, take frequent rests, and carry the greatest loads possible. We observed, for example, a group of heavily loaded porters making slow headway up a steep ascent out of a river gorge. Following whistled commands from their leader, they would take up their loads and labor uphill for no more than 15 s at a time, followed by a 45-s period of rest. Incredibly, this group of barefoot porters was headed for Tibet, across the Nangpa glacier (altitude 5716 m [18,700 ft]), about another week’s travel beyond Namche.
So how do they do it? They might reduce the muscular work required to carry a load or increase their overall efficiency. The actual mechanism is unknown at this time.
Many world mountain climbers brag if they make it up Everest, but these sherpas consider such feats all in a day’s work. National Geographic News adds that after unloading and selling their goods, they race home for more, running down the mountain for two days, even poorly equipped and usually with very bad shoes or none at all. They usually sleep on the trail, with nothing but rocks for pillows, even in below-freezing temperatures. Some of their women bring their babies with them.
See also the National Geographic story from May 2002 about the legendary Sherpas of Mt. Everest. Many of the famous climbing expeditions on the world’s highest mountain could not have succeeded without them, it says.
1Bastien et al., “Energetics of Load Carrying in Nepalese Porters,” Science, Vol 308, Issue 5729, 1755 , 17 June 2005, [DOI: 10.1126/science.1111513].
Every once in awhile we get glimpses into the suggestion that there is far more potential in the human body than most of us realize. Those of us who have backpacked in the mountains know the strain of carrying even 40 pounds up a steep mountainside for just a couple of hours, and that at much lower elevations. The worst feeling at a rest stop is to have some 68-year-old frail-looking grandma with a bigger pack prance right on by saying, “Mighty fine day, is it not?” as you sit there gasping for breath.
Here we see, in Nepal, a community of men, women and children that make the impossible look routine. They don’t shop at REI and use Patagonia gear or high-tech climbing boots; they don’t compete in the Olympics or win medals, but all of us must regard the way of life of these human mountain goats with admiration. How much stronger and smarter could our ancestors have been? A little humility is always in order.