Basal metabolic rate and energy costs at rest and during exercise in rural- and urban-dwelling Papua New Guinea highlanders

Objective: (1) To evaluate inter-individual variations, regional and sex differences in the basal metabolic rate (BMR) and related variables; (2) to compare measured BMR with estimated BMR using predictive equations; and (3) to examine the net mechanical efficiency (NME) in step tests. Design: BMR and energy costs at rest and during step tests were measured by the Douglas bag technique of indirect calorimetry. NME was calculated from BMR and energy costs of step tests. Setting: Rural villages under subsistence agriculture and urban settlements under cash economy. Subjects: Adult males and females (n=33) including 16 rural villagers and 17 urban migrants. Interventions: Step exercise test. Results: There were significant regional differences in BMR (per body weight) in both sexes. The BMR predicted by Schofield equation correlated with the measured BMR (- 1 to + 3%), while the BMR predicted by Henry and Rees equations under-estimated the measured BMR by 6-11%. NME was higher in urban subjects with larger body size than in rural subjects for both sexes, albeit insignificantly. NME tended to be higher with increased stepping level in both sexes. Conclusions: Urban migrants had lower BMR than rural dwellers, and the BMR predicted by Schofield equation correlated with the measured BMR in both sub-groups. Sponsorship: The United Nations University Project on People, Land Management and Environmental Change. Descriptors: basal metabolic rate; resting metabolic rate; step test; net mechanical efficiency; Papua New Guinea; rural and urban comparison
Introduction The FAO/WHO/UNU Expert Consultation (1985) adopted the principle of relying on estimates of energy expenditure to assess the energy requirements of adults. Basal metabolic rate (BMR) constitutes between 60 [...]