Gurven Michael D, Trumble Benjamin C, Stieglitz Jonathan, Yetish Gandhi, Cummings Daniel, Blackwell Aaron D, Beheim Bret, Kaplan Hillard S, Pontzer Herman
Department of Anthropology, University of California Santa Barbara, Santa Barbara, CA.
Institute for Advanced Study in Toulouse, Toulouse, France.
Am J Phys Anthropol. 2016 Nov;161(3):414-425. doi: 10.1002/ajpa.23040. Epub 2016 Jul 4.
Resting metabolic rate (RMR) reflects energetic costs of homeostasis and accounts for 60 to 75% of total energy expenditure (TEE). Lean mass and physical activity account for much RMR variability, but the impact of prolonged immune activation from infection on human RMR is unclear in naturalistic settings. We evaluate the effects of infection on mass-corrected RMR among Bolivian forager-horticulturalists, and assess whether RMR declines more slowly with age than in hygienic sedentary populations, as might be expected if older adults experience high pathogen burden.
RMR was measured by indirect calorimetry (Fitmate MED, Cosmed) in 1,300 adults aged 20 to 90 and TEE was measured using doubly labeled water (n = 40). Immune biomarkers, clinical diagnoses, and anthropometrics were collected by the Tsimane Health and Life History Project.
Tsimane have higher RMR and TEE than people in sedentary industrialized populations. Tsimane RMR is 18 to 47% (women) and 22 to 40% (men) higher than expected using six standard prediction equations. Tsimane mass-corrected TEE is similarly elevated compared to Westerners. Elevated leukocytes and helminths are associated with excess RMR in multivariate regressions, and jointly result in a predicted excess RMR of 10 to 15%. After age 40, RMR declines by 69 kcal/decade (p < .0001). Controlling for lean mass and height accounts for 71% of age-related RMR decline, and adding indicators of infection minimally affects the age slope. The residual level of age-related decline from age 40 is 1.2% per decade.
High pathogen burden may lead to higher metabolic costs, which may be offset by smaller body mass or other energy-sparing mechanisms.
静息代谢率（RMR）反映内稳态的能量消耗，占总能量消耗（TEE）的60%至75%。去脂体重和身体活动是RMR个体差异的主要影响因素，但在自然环境中，感染导致的长期免疫激活对人类RMR的影响尚不清楚。我们评估了感染对玻利维亚觅食-园艺人群校正体重后的RMR的影响，并评估RMR随年龄下降的速度是否比卫生条件较好的久坐人群更慢，这可能是因为老年人面临较高的病原体负担。
采用间接测热法（Fitmate MED，科迈德公司）测量了1300名20至90岁成年人的RMR，并使用双标水法测量了TEE（n = 40）。齐曼内健康与生活史项目收集了免疫生物标志物、临床诊断和人体测量数据。
齐曼内人的RMR和TEE高于久坐的工业化人群。使用六个标准预测方程，齐曼内女性的RMR比预期高18%至47%，男性高22%至40%。与西方人相比，齐曼内人校正体重后的TEE同样升高。在多变量回归中，白细胞和寄生虫水平升高与RMR过高有关，共同导致预测的RMR过高10%至15%。40岁以后，RMR每十年下降69千卡（p <.0001）。控制去脂体重和身高可解释与年龄相关的RMR下降的71%，添加感染指标对年龄斜率的影响最小。40岁以后与年龄相关的下降的残余水平为每十年1.2%。
高病原体负担可能导致更高的代谢成本，这可能被较小的体重或其他节能机制所抵消。
