A male Rai porter carrying a load equal to 100% of his body weight during the oxygen consumption measurements in Phakding. The instrumented mask and analyzer/transmitter are clearly shown, as well as the track and several photocells. The footpath between the Kathmandu valley and Mt. Everest, along the split-rail fence, is shown in the background. The load carrying strategy adopted by the Nepalese porters is to maximize the load carried, walk slowly, and take frequent rests during their long dawn-to-dusk workdays. Credit: Science.