The mitochondrion is often referred as the cellular powerhouse because the organelle oxidizes organic acids and NADH derived from nutriments, converting around 40% of the Gibbs free energy change of these reactions into ATP, the major energy currency of cell metabolism. Mitochondria are thus microscopic furnaces that inevitably release heat as a by-product of these reactions, and this contributes to body warming, especially in endotherms like birds and mammals. Over the last decade, the idea has emerged that mitochondria could be warmer than the cytosol, because of their intense energy metabolism. It has even been suggested that our own mitochondria could operate under normal conditions at a temperature close to 50 °C, something difficult to reconcile with the laws of thermal physics.

Here, using our combined expertise in biology and physics, we exhaustively review the reports that led to the concept of a hot mitochondrion, which is essentially based on the development and use of a variety of molecular thermosensors whose intrinsic fluorescence is modified by temperature. Then, we discuss the physical concepts of heat diffusion, including mechanisms like phonons scattering, which occur in the nanoscale range. Although most of approaches with thermosensors studies present relatively sparse data and lack absolute temperature calibration, overall, they do support the hypothesis of hot mitochondria. However, there is no convincing physical explanation that would allow the organelle to maintain a higher temperature than its surroundings. We nevertheless proposed some research directions, mainly biological, that might help throw light on this intriguing conundrum.

线粒体通常被称为细胞动力源，因为细胞器会氧化来自营养的有机酸和NADH，将这些反应的吉布斯自由能变化的约40％转化为ATP（ATP是细胞代谢的主要能量货币）。因此，线粒体是显微炉，不可避免地会释放热量，这些热量是这些反应的副产物，尤其是在鸟类和哺乳动物的吸热中，这会导致人体变暖。在过去的十年中，已经出现了一种想法，即线粒体会因为其强烈的能量代谢而比胞浆更温暖。甚至有人提出，我们自己的线粒体可以在接近50°C的正常条件下运行，这很难与热物理定律相协调。

在这里，利用我们在生物学和物理学领域的专业知识，我们详尽地回顾了导致热线粒体概念的报告，该理论主要基于各种分子热敏传感器的开发和使用，其分子内的荧光会随温度而改变。然后，我们讨论了热扩散的物理概念，包括声子散射等发生在纳米范围内的机制。尽管大多数使用热传感器进行研究的方法都提供了相对稀疏的数据，并且缺乏绝对温度校准，但总的来说，它们确实支持热线粒体的假设。但是，没有令人信服的物理解释可以使细胞器保持比周围环境更高的温度。不过，我们提出了一些研究方向，主要是生物学方面的研究，