Xu Xiaojiang, Rioux Timothy P, Castellani Michael P
US Army Research Institute of Environmental Medicine, Thermal and Mountain Medicine Division, Natick, MA, USA.
Oak Ridge Institute for Science and Education.
Temperature (Austin). 2022 Jul 22;10(2):235-239. doi: 10.1080/23328940.2022.2088034. eCollection 2023.
The specific heat capacity of the human body is an important value for heat balance analysis in thermoregulation and metabolism research. The widely used value of 3.47 kJ · kg· °C was originally based on assumptions and was not measured or calculated. The purpose of this paper is to calculate the specific heat of the body, defined as the mass-weighted mean of the tissue specific heat. The masses of 24 body tissue types were derived from high-resolution magnetic resonance images of four virtual human models. The specific heat values of each tissue type were obtained from the published tissue thermal property databases. The specific heat of the entire body was calculated to be approximately 2.98 kJ · kg · °C and ranged from 2.44 to 3.39 kJ · kg · °C depending on whether min or max measured tissue values were used for the calculation. To our knowledge, this is the first time specific heat of the body has been calculated from the measured values of individual tissues. The contribution of the muscle to the specific heat of the body is approximately 47%, and the contribution of the fat and skin is approximately 24%. We believe this new information will improve the accuracy of calculations related to human heat balance in future studies of exercise, thermal stress, and related areas.
人体的比热容是体温调节和新陈代谢研究中热平衡分析的一个重要数值。广泛使用的3.47kJ·kg·°C这一数值最初是基于假设得出的，并非实测或计算所得。本文的目的是计算人体的比热容，即组织比热容的质量加权平均值。24种人体组织类型的质量来自四个虚拟人体模型的高分辨率磁共振图像。每种组织类型的比热容值取自已发表的组织热特性数据库。计算得出人体的比热容约为2.98kJ·kg·°C，根据计算时使用的是测量的组织最小值还是最大值，其范围在2.44至3.39kJ·kg·°C之间。据我们所知，这是首次根据各个组织的测量值来计算人体的比热容。肌肉对人体比热容的贡献约为47%，脂肪和皮肤的贡献约为24%。我们相信，这一新信息将提高未来运动、热应激及相关领域研究中人体热平衡计算的准确性。
