Commercial porters of eastern Nepal: Health status, physical work capacity, and energy expenditure

The purpose of the study was to compare full-time hill porters in eastern N epal with part-time casual porters engaged primarily in subsistence farming . The 50 porters selected for this study in Kenja (elevation 1,664 m) were young adult males of Tibeto-Nepali origin. Following standardized interview s, anthropometry, and routine physical examinations, the porters were teste d in a field laboratory for physiological parameters associated with aerobi c performance. Exercise testing, using a step test and indirect calorimetry , included a submaximal assessment of economy and a maximal-effort graded e xercise test. Energy expenditure was measured in the field during actual tu mpline load carriage. No statistically significant differences were found b etween full-time and part-time porters with respect to age, anthropometric characteristics, health, nutritional status, or aerobic power. Mean (V) ove r dot O-2 peak was 2.38 +/- 0.27 L/min (47.1 +/- 5.3 ml/kg/min). Load-carry ing economy did not differ significantly between porter groups. The relatio nship between (V) over dot O-2 and load was linear over the range of 10-30 kg with a slope of 9 +/- 4 ml O-2/min per kg of load. During the field test of actual work performance, porters expended, on average, 348 +/- 68 kcal/ hr in carrying loads on the level and 408 +/- 60 kcal/hr in carrying loads uphill. Most porters stopped every 2 min, on average, to rest their loads b riefly on T-headed resting sticks (tokmas). The technique of self-paced, in termittent exercise together with the modest increase in energy demands for carrying increasingly heavier loads allows these individuals to regulate w ork intensity and carry extremely heavy loads without creating persistent m edical problems. Am. J. Hum. Biol. 13:44-56, 2001. (C) 2001 Wiley-Liss, Inc .