Basal metabolic adaptation of the Evenki reindeer herders of Central Siberia.

Previous research has suggested that basal metabolic rates (BMRs of indigenous circumpolar populations are elevated, perhaps as an adaptation to chronic, severe cold stress. This study examines variation in BMR among indigenous (Evenki) and nonindigenous (Russian immigrant) populations living in Central Siberia to determine: 1) whether the Evenki show evidence of increased metabolic rates, and 2) whether the metabolic responses of the Evenki are different from those of the recent Russian migrants ("controls"). BMRs were measured among 58 Evenki (19 men, 39 women) and 24 Russian (8 men, 16 women) adults (18-56 years of age) from three Siberian villages. Measured BMRs were compared to those predicted based on body weight and body SA (Consolazio et al., 1963; Schofield, 1985a,b). BMRs per unit weight and FFM were similar in Evenki and Russian men, whereas Evenki women had higher BMRs than their Russian peers. Relative to the Schofield (body weight) norms, Evenki men and women and Russian men all showed modest elevations in BMR, whereas Russian women had lower than expected BMRs. Compared to the Consolazio (surface area) estimates, both Evenki men and women showed significant elevations in BMR. Russian men also showed higher than expected BMRs, while those of Russian women were slightly below predicted levels. Age-related declines in BMR were evident among the women of both ethnic groups, but not among the men. Additionally, residence location was an important predictor of metabolic variation in the Evenki, with those of the more traditional village showing greater elevations in BMR. These results suggest that the Evenki display elevated metabolic needs, and this long-term adaptation reflects the interaction of genetics and level of acculturation. Am. J. Hum. Biol. 12:75-87, 2000. Copyright 2000 Wiley-Liss, Inc.