Introduction:
After death, heat production stops due to the cessation of physical, chemical, and metabolic activity. Thus, the body starts to cool and, within a few hours, becomes equal to the surrounding temperature. This is called Algor mortis.
Heat is lost from the atmosphere through conduction, evaporation (convection), and radiation, and from water through conduction and convection. It was believed that heat is lost at the same rate in all body parts. However, the outer core (skin) loses heat much more quickly than the inner core, which barely loses any heat at all. This is because the skin and fatty tissue act as insulators, slowing down heat loss.
The inner core’s temperature falls in a curve that looks like an “S” instead of a straight line. Therefore, the inner core’s temperature is more critical and reliable for determining the time of death. To record the temperature of the body’s inner core, one can take measurements using a chemical thermometer with a range of graduations from 0 to 50⁰C. There are two commonly used sites on the body to measure this temperature: the rectum, located about 4 inches above the anus, and the subhepatic area. The rectum is a more commonly used site because it is closer to the body’s core and thus provides a more accurate measurement of the core temperature.
Factors that Affect the Cooling of a Dead Body
- The temperature of the body at the moment of death: Body temperature at the moment of death is uncertain, which can make accurately calculating the time of death challenging. Therefore, it is crucial to account for this factor during forensic investigations.
- The temperature difference between the body and the surroundings: The more significant the difference between these two temperatures, the faster the fall rate. This is because heat tends to flow from areas of higher temperature to lower temperature, causing the body’s temperature to decrease more quickly when there is a more significant temperature difference between it and the surroundings.
- Media of disposal of the body: Body disposal methods affect the cooling rate of a dead body. The body cools faster in water than in air and is slowest when buried underground.
- Clothing and coverings: Clothing acts as an insulator, which means it slows the heat loss process through conduction and convection. When the body is exposed to cold air or water, heat is lost faster, which can lead to more rapid cooling of the body. However, when the body is covered with clothing or other insulating materials, the rate of heat loss is reduced, which can help to slow down the cooling process. In addition to reducing the heat transfer rate, clothing, and coverings can also help protect the body from environmental factors that could accelerate the cooling process. For example, clothing can provide protection from wind and rain, which can cause the body to lose heat more rapidly. It can also protect from the sun’s UV rays, which can cause damage to the skin and accelerate the decomposition process.
- Body-built (the size factor): When considering cooling, assessing a person’s size is essential. This is the ratio of the surface area of their body that is exposed to cooling compared to their body mass. Children and small adults will cool down faster than average adults because they have a larger surface area compared to their mass.
- Air current and humidity: Air movement and moisture play a crucial role in the cooling process of a body. When air moves efficiently over the skin, it helps bring cooler air in contact with the body, thus encouraging heat loss. In contrast, when insufficient air movement, the body’s cooling process slows down. Moreover, moisture in the air also affects the body’s cooling rate. Damp air conducts heat more quickly than dry air, which can cause the body to lose heat faster.
- Sex: Studies have shown that female bodies tend to retain body heat for a more extended period than male bodies due to their higher body fat percentage, lower metabolic rate, and the effects of the menstrual cycle.
- Position and posture of the body: The position and posture of the body, along with clothing and coverings, are essential factors that affect the cooling of a dead body. When the body’s limbs are outstretched, the body’s surface area increases, leading to an increased rate of heat loss.
- Postmortem caloricity: It is a phenomenon that occurs when the body temperature rises after death rather than decreases. This can happen due to various factors, such as postmortem glycogenolysis, a process that occurs in all dead bodies soon after death and can produce up to 140 calories, raising the body temperature by approximately 2° C. However, in certain conditions such as asphyxial deaths, poisoning due to alcohol, datura, or strychnine, drug reactions, heat stroke, brainstem hemorrhage, and deaths due to infectious diseases, there is a further rise in body temperature.
The Significance of Cooling in Determining Time of Death:
Body cooling is a crucial factor in postmortem investigations, as it can provide valuable information for forensic pathologists. Cooling, or “algor mortis,” is a gradual reduction in body temperature that occurs after death. This cooling process can help to estimate the time of death, which is a critical piece of information in many criminal investigations.
The cooling rate can vary depending on numerous factors, such as the environment and the individual’s body composition. However, it is possible to roughly estimate the time of death based on the rectal temperature at the time of death and the rate of fall of body temperature per hour.
Time passed after death in hours = Rectal temperature at the time of death/rate of fall of body temperature per hour.
Forensic pathologists can use this information to determine critical details about the death, such as the approximate time of death and other relevant information about the circumstances surrounding the individual’s passing.
Conclusion
In conclusion, cooling the dead body is an essential aspect of forensic investigations that provides valuable information to estimate the time of death and other vital details.
