Nepal Porters Seen as Heavyweights

Able to carry a fifth of their body weight with virtually no effort, porters in the mountains of Nepal are the most efficient human haulers ever described, a study published in the current issue of the journal Science has found.

Guillaume Bastien and colleagues at Belgium’s Universite catholique de Louvain analyzed the porters’ efficiency by measuring their oxygen consumption and carbon dioxide production, both of which reflected how much energy was used.

Compared with previously measured European backpackers, the porters in Nepal used less additional energy to carry increasingly heavy loads. The Nepalese could carry loads equal to their own weight using roughly the same extra energy the Europeans required to carry less than 20% of their body weight.

This level of efficiency is higher than even African women who were previously shown to be remarkably adept at carrying heavy loads on their heads.

The researchers studied a group of Nepalese porters traveling 60 miles from their homes in the Kathmandu Valley to Namche, a town in the shadows of Mt. Everest. The journey can typically take a week, requiring the porters to climb and descend several miles in elevation.

Slinging baskets across their backs, but bearing the weight primarily with straps across their heads, the men can typically carry at least 90% of their body weight and the women about 70%.

Roughly a fifth of these men carry loads in excess of their body weight, and some occasionally manage about twice that amount.

“They’re certainly the most efficient people ever studied,” said researcher Norman Heglund, a physiology professor at Louvain. “Small, incremental increases in efficiency add up to a big sum. For example, their muscular efficiency tends to be a bit higher. There’s no mystery about that. They eat nothing but carbohydrates.”