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.