Monnard Cathríona R, Miles-Chan Jennifer L
Department of Medicine / Physiology, University of Fribourg, Chemin du Musée 5, Fribourg, Switzerland.
PLoS One. 2017 Jan 5;12(1):e0169478. doi: 10.1371/journal.pone.0169478. eCollection 2017.
The disease risks associated with sedentary behavior are now firmly established, and consequently there is much interest in methods of increasing low-intensity physical activity. In this context, it is a widely held belief that altering posture allocation can modify energy expenditure (EE) to impact upon body weight regulation and health. However, we recently showed the existence of two distinct phenotypes pertaining to the energy cost of standing-with the majority of a Caucasian cohort showing no sustained increase in EE during standing relative to sitting. Here we investigated whether this phenomenon is also observed across a multi-ethnic male cohort.
To determine the magnitude and time-course of changes in EE and respiratory quotient (RQ) during steady-state standing versus sitting, and to explore inter-individual variability in these responses across 4 ethnic groups (European, Indian, Chinese, African).
Min-by-min monitoring using posture-adapted ventilated-hood indirect calorimetry was conducted in 35 healthy, men (20-43 years) during 10 min of steady-state standing versus sitting comfortably.
69% of subjects showed little or no increase (<5%) in EE during standing compared to sitting (energy savers). Furthermore, the proportion of energy savers did not significantly differ between ethnic groups, despite ethnic differences in anthropometry; with body weight as the primary predictor of the energy cost of standing maintenance (r2 = 0.30, p = 0.001).
Our results indicate that the majority of individuals in a multi-ethnic cohort display a postural energy-saver phenotype. The mechanisms by which the large majority of individuals appear to maintain sitting and standing postures at the same energetic cost remains to be elucidated but is of considerable importance to our understanding of the spontaneous physical activity compartment of EE and its potential as a target for weight regulation.
久坐行为相关的疾病风险现已明确确立，因此人们对增加低强度身体活动的方法极为关注。在此背景下，人们普遍认为改变姿势分配可以改变能量消耗（EE），从而影响体重调节和健康。然而，我们最近发现存在两种与站立能量消耗相关的不同表型——在一个白种人队列中，大多数人站立时的EE相对于坐着时没有持续增加。在此，我们研究了这种现象在多民族男性队列中是否也存在。
确定稳态站立与坐着时EE和呼吸商（RQ）变化的幅度和时间进程，并探讨这4个种族群体（欧洲人、印度人、中国人、非洲人）在这些反应中的个体间差异。
对35名健康男性（20 - 43岁）进行逐分钟监测，使用适合姿势的通风面罩间接测热法，分别记录他们舒适地站立和坐着10分钟时的情况。
69%的受试者站立时的EE相对于坐着时几乎没有增加或增加极少（<5%）（能量节省者）。此外，尽管不同种族在人体测量学上存在差异，但能量节省者的比例在不同种族之间没有显著差异；体重是维持站立能量消耗的主要预测因素（r2 = 0.30，p = 0.001）。
我们的结果表明，多民族队列中的大多数个体表现出姿势能量节省表型。大多数个体似乎以相同的能量成本维持坐姿和站姿的机制仍有待阐明，但这对于我们理解EE中的自发身体活动部分及其作为体重调节靶点的潜力具有相当重要的意义。
