Nepalese porters are the most efficient human load carriers yet recorded. They beat the former champions, African women balancing burdens on their heads, says Norman Heglund of the Catholic University of Louvain in Belgium. He and his colleagues observed porters, ages 11 to 68, on a footpath at 2,800 meters elevation.
For men, loads averaged 93 percent of body weight but went up to 183 percent. Women's loads averaged 66 percent. The researchers fitted breathing monitors to some porters and documented that they could carry 60 percent of their body weight using half the energy that young Europeans use to carry backpacks. The porters walk slowly and rest often but go many hours with big loads, the team notes in the June 17 Science.