From the Guidelines
Body temperature regulation is crucial for maintaining optimal enzyme function and cellular processes, and it is maintained through a complex system controlled by the hypothalamus in the brain, which acts like the body's thermostat, with a normal temperature range near 37° C. According to the 2024 American Heart Association and American Red Cross guidelines for first aid 1, heat loss occurs through 4 methods: conduction, convection, radiation, and evaporation. Hypothermia occurs when the core body temperature drops below the normal temperature range, and it can progress through predictable stages to death.
Key Points to Consider
- The very young, the very old, and people with impaired temperature perception, regulation, and ability to communicate are at increased risk of hypothermia 1.
- Rewarming may use passive measures, such as protecting from further heat loss and allowing the body to rewarm itself, or active measures, such as applying external sources of heat to the body 1.
- Normal body temperature averages around 98.6°F (37°C), with slight variations throughout the day, and fever is a controlled increase in body temperature, typically triggered by immune responses to infection.
Signs and Symptoms
- Individuals may be “cold” or “cold stressed” with temperatures of 35° C to 37° C, and mild hypothermia begins when the core temperature falls below 35° C 1.
- First aid providers are unlikely to be able to obtain core body temperatures, so assessment and treatment decisions must be guided by signs and symptoms.
Prevention and Treatment
- To support healthy temperature regulation, stay hydrated, dress appropriately for environmental conditions, and be aware of signs of heat exhaustion or hypothermia, which require prompt medical attention if severe.
- Temperature regulation can be compromised in very young children, the elderly, and those with certain medical conditions, and it is essential to take preventive measures to avoid hypothermia, especially in high-risk individuals 1.
From the Research
Regulation of Body Temperature
The regulation of body temperature is a complex process that involves various physiological mechanisms to maintain a stable core temperature despite changes in environmental conditions.
- Hypothermia, a condition where the core temperature drops below 35°C, can be life-threatening and requires prompt treatment. Studies have shown that therapeutic peritoneal lavage with warm saline solution can be an effective option for rewarming critically hypothermic patients 2, 3.
- Peritoneal lavage involves the infusion of warm saline solution into the peritoneal cavity to rapidly increase the core temperature. This technique has been shown to be successful in treating severe accidental hypothermia 2, 3.
- In addition to peritoneal lavage, other rewarming techniques such as radio wave regional hyperthermia have been studied. A controlled comparison of radio wave regional hyperthermia and peritoneal lavage rewarming after immersion hypothermia found that radio wave therapy was superior to peritoneal lavage for core rewarming 4.
- The use of automated peritoneal lavage systems has also been explored as a means of rapidly inducing and maintaining hypothermia in patients after cardiac arrest or acute myocardial infarction. Studies have shown that this technique can be safe and effective in cooling patients to a target temperature of 32.5°C 5.
- Human temperature regulation is a homeostatic feedback control system that ensures deep body temperature is maintained within narrow limits despite wide variations in environmental conditions and activity-related elevations in metabolic heat production. Various factors such as morphology, heat adaptation, biological sex, and age can influence deep body temperature during exercise and/or exposure to hot ambient temperatures 6.