Why Do We ‘Feel Cold?
Dr. Warner here –
Our bodies are programmed to notice changes in temperature. As the temperature drops, or if we catch a chill, our body responds with goosebumps or shivering. This is due to the body’s nerve receptors and how they react to the environment. Let’s take a deeper look at how the body processes cold.
How the Body Processes Cold
It is said that even a 1-degree change in air temperature is felt and can be healing in a sense. The skin is filled with temperature sensing nerve receptors. Receptors are a part of the nerve that receives a stimulus from the environment. Such stimuli may be pressure, tearing, cold, hot, or chemical, among others. To sense cold, the brain uses cold-receiving cell receptors. These have been named TRPs. For cold, the body typically uses TRPM8.
TRPM8 is a calcium channel and is voltage-gated. As the temperature changes, the receptor releases calcium and changes the charge of the cell. That charge becomes an action potential and sends an electric signal to the brain. In the brain, that signal is interpreted as what we know as ‘cold.’ TRPM8 only fires within a certain range or temperature or if substances, such as menthol, eucalyptol, or icilin (AG-3-5), hit the receptor.
The cold receptors normally function at a ‘steady-state.’ That is, they maintain a certain level of electric discharge and the brain interprets this as the normal room temperature or skin temperature. When a cold stimulus is applied (an ice cube for example), the signal changes rapidly and that change is interpreted as cold. These are slowly conducting receptors that have a very dynamic response to temperature change.
The Range of Cold Sensation
The body can sense between a general cooling that is pleasant (<30C to 15C) and that which is painful and damaging (<15C). Different receptors sense each of the possible different ranges of temperature.
There is a molecular foundation for thermoreception. We think there are about 28 different cation-permeable ion channels of the TRP group (transient receptor potential) which all respond to a very large range of stimuli.
TRPM8 (transient receptor potential melastatin 8) responds to innocuous cold or cooling. This receptor sends a signal to the brain when the temperature changes only a little bit. There is also another receptor known as the cold/menthol receptor 1 (CRM1). Other TRP receptors are engaged when the temperature becomes so cold as to be painful and noxious.
Your Source For Information
The body is intricately wired to experience various sensations – the feeling of being cold is just one of many.
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Meredith Warner, MD