Hypothermia refers to a state in which deep body temperature (rectum, esophagus, tympanum) is lower than 35 ° C . Hypothermia can lead to death directly or indirectly. If the body temperature drops below 32 ° C , human organs will not be able to metabolize and work normally. Biologically, animals are divided into two types: " warm-blooded animals " and "ectotherms."
The body temperatures of mammals and birds are mostly constant. Cold-blooded animals (commonly known as cold-blooded animals) refer to animals other than mammals and birds. Most animals on earth are cold-blooded. Because the bodies of ectothermic animals have no mechanism to regulate body temperature, the animals can only rely on their own behavior to regulate the loss of body temperature, or absorb heat from the external environment to increase their own body temperature. When the temperature of the external environment increases, the animal's metabolic rate increases, its body temperature gradually rises, and it passively leaves the unfavorable environment. When the external environment temperature decreases, the animal's metabolic rate also decreases, and the body temperature gradually decreases.

In living systems, the thermodynamic states and interactions between different molecules are very important. For example, in the processes of protein folding and enzyme catalysis, changes in thermodynamic energy and entropy caused by intermolecular interactions are important factors affecting the success of these processes. The thermodynamic environment of biological systems also plays a regulatory role. For example, changes in body temperature will directly affect the metabolic rate and oxygen consumption of cells, thereby affecting the health of the body.
In the field of biomedical engineering, heat flow sensors and temperature sensors are widely used in vital sign monitoring, disease diagnosis and treatment as important detection technologies. Based on the application of sensors, biomedical engineering technology can improve the monitoring accuracy of physiological characteristics such as human body temperature and thermal effects, as well as the accuracy of disease diagnosis and treatment, which is of great significance to promoting human health.
In the process of clinical diagnosis and treatment, through body temperature monitoring technology based on temperature sensors, doctors can quickly and accurately obtain the patient's body temperature, judge the condition in a timely manner, and make effective medical decisions. At the same time, in an environment where hot and cold alternate, when researchers perform complex tasks, temperature sensors can also help researchers monitor and analyze the thermal effects of the human body in real time to prevent the human body from being stimulated by overheating or overcooling.

Gongcai.com represents multiple brands of heat flow sensors and temperature sensors that can detect human body temperature and heat flow transfer, such as the following:
Japan's EKO heat flow sensor - HF-10S , uses thermocouples to test temperature differences, and the passing heat flow can be measured directly. The coefficient 1/R is initially calibrated with a standard heat flow sensor. If the sensor is placed inside the material, it directly measures the heat transfer produced by thermal conduction.
Japan's EKO heat flow sensor - MF-180 is suitable for direct measurement of heat flow inside materials , and is also suitable for measurement of radiant flow of refrigerants. If the heat flow sensor is placed on the surface of the material , it will measure the sum of the three modes of heat conduction , heat radiation and heat flow.
German HLP infrared temperature sensor - TS318-1B0814 : Mainly used for non-contact measurement , its function is to convert the thermal radiation emitted by the object into voltage output.

Dutch Smartec ultra-low power consumption, high-precision digital output temperature sensor - SMT172 : It is a new ultra-low power consumption , high-precision digital output temperature sensor. It has stable performance, easy use and wide measuring temperature range. It is a single crystal silicon integrated circuit that applies new design principles and adopts high-precision single temperature point calibration.