The human body maintains a consistent internal temperature through thermoregulation, a process of generating and dissipating heat to keep the body within a narrow, healthy range. Blankets help maintain warmth, particularly when the ambient environment is cooler than the body’s ideal temperature.
How Blankets Keep You Warm
Blankets do not generate heat; instead, they work by trapping the heat naturally produced by your body. This mechanism relies on the principles of insulation and reducing heat loss. Blankets create a thermal barrier that minimizes heat transfer from your body to the cooler surrounding air.
A blanket’s effectiveness stems from its ability to trap still air within its fibers, which acts as a natural insulator. Air is a poor conductor of heat. By holding a layer of this warmed air close to the body, blankets prevent heat from escaping through conduction (direct contact), convection (movement of fluids), and radiation (electromagnetic waves). This inhibition of heat transfer creates a warmer microenvironment around you.
What Influences Temperature Increase
The degree to which a blanket can raise body temperature is not a fixed number, as it depends on several interacting factors. On average, a blanket might increase body temperature by approximately 2 to 5 degrees Fahrenheit (1 to 3 degrees Celsius), but this range is highly variable.
The ambient room temperature significantly influences a blanket’s effect; colder environments lead to more noticeable warming due to a greater temperature difference. The type and number of blankets also play a role, as different materials offer varying levels of insulation. Wool and fleece, for instance, are effective at retaining heat, while cotton is more breathable and provides less insulation. Thicker, denser materials and multiple layers enhance insulation.
An individual’s metabolism also affects how much warmth a blanket provides. People with higher metabolic rates generate more body heat, which can be more effectively trapped. The duration of blanket use matters; longer coverage allows more heat to accumulate. Additionally, clothing worn underneath blankets contributes to overall insulation.
Staying Safe with Blankets
While blankets are effective for warmth, it is important to be aware of overheating, also known as hyperthermia. Prolonged or excessive use, especially in warm environments, can raise body temperature to uncomfortable or unsafe levels. Symptoms include excessive sweating and discomfort, which may resemble a fever, though blankets alone do not cause a true fever.
Certain individuals are particularly vulnerable to overheating, including infants, the elderly, and those with medical conditions that affect temperature regulation, such as diabetes. Infants, for example, can overheat easily, and materials like fleece or multiple folded blankets are not recommended for them due to reduced breathability and increased heat retention.
To use blankets safely:
Avoid excessive layers, especially in warmer rooms.
If using an emergency blanket, wrap it loosely for air circulation, preventing excessive heat build-up.
For heated blankets, do not use them overnight and turn them off before sleeping to prevent burns or overheating.
Ensure proper ventilation and recognize signs of discomfort to prevent adverse health effects.