HRRBAA: The metabolic cost of living among herders

总能量消耗受限假说表明，面对高水平的身体活动，人体会努力减少每天消耗的卡路里总量。然而，人类生活在一个狭窄的代谢范围内的观点还没有在不同的气候和季节得到广泛的验证。为了进一步证实这一假设，这个高风险的研究项目将评估在高度活跃的寒冷气候人群中测量能量消耗和棕色脂肪组织激活的可行性。这一努力所产生的基础人类生物学研究将使我们了解新陈代谢和棕色脂肪组织与现代世界肥胖流行的关系。这项研究将支持本科生和研究生的研究培训和指导、国际合作以及向当地社区的科学推广。研究结果将在同行评审期刊上发表，并纳入奥尔巴尼大学的本科和研究生课程。使用弹性心率和双标签水法，总能量消耗（每天燃烧的卡路里）将在牛群聚集期间测量，这大约持续一个星期，在深秋。在此期间，身体活动水平（用于估计和比较能量消耗）和饮食摄入量也将被记录下来。每位受试者的静息代谢率、年龄、性别、体重、体脂率、肌肉量、葡萄糖水平和胆固醇水平将被记录下来。这些数据将用于制定代谢概况，确定在不同的活动和休息期间消耗了多少卡路里。能量消耗测量值将与估估值进行比较，以确定牧民消耗的卡路里是否少于预期（如人类能量消耗的新约束理论所假设的那样），或者测量值是否反映了居住在恶劣环境中所需的更高能量需求。最后，一种采用热成像相机的新程序将用于测量棕色脂肪组织在野外的激活。通常，褐色脂肪组织研究是在临床环境中进行的，需要PET-CT扫描；本研究中使用的程序对于该领域的研究人员和研究参与者都更加灵活。该项目将作为开展纵向研究的跳板，研究季节对总能量消耗、身体活动水平、棕色脂肪组织激活的影响，以及解决肥胖流行病的应用。

The constrained total energy expenditure hypothesis suggests that in the face of high levels of physical activity the human body works to reduce the overall number of calories burned each day. However, the idea that humans live within a narrow metabolic range has not been broadly tested across climates and seasons. To further address this hypothesis, this high-risk research project will assess feasibility of measuring energy expenditure and brown adipose tissue activation in a highly active cold-climate population. The fundamental human biology research that would result from this effort will inform our understanding of how metabolism and brown adipose tissue relate to the obesity epidemic in the modern world. The research will support research training and mentoring for undergraduate and graduate students, international collaborations, and science outreach to local communities. Results will be disseminated in peer review journals as well as incorporated into undergraduate and graduate curricula at the University at Albany. Using the flex-heart rate and doubly labeled water methods, total energy expenditure (calories burned each day) will be measured during the herd round-up, which lasts roughly one week during the late fall. Physical activity levels (used to estimate and compare energy expenditures) and dietary intake will also be documented during this time. Resting metabolic rate, age, sex, body mass, body fat percentage, muscle mass, glucose levels, and cholesterol levels will be recorded for each subject. These data will be used to develop a metabolic profile, determining how many calories are used for different activities and during rest. Energy expenditure measurements will be compared to estimates to determine if herders expend fewer calories than expected, as hypothesized by the new constrained theory for human energy expenditure, or if the measurements reflect a higher energetic demand required by inhabiting a harsh environment. Finally, a new procedure employing a thermal imaging camera will be used to measure brown adipose tissue activation in the field. Typically, brown adipose tissue studies take place in clinical settings and require PET-CT scans; the procedure used in this study is more flexible for both researchers and study participants in the field. This project will act as a spring board for developing a longitudinal study examining seasonal impacts on total energy expenditure, physical activity levels, brown adipose tissue activation, and applications for addressing the obesity epidemic.