Why do we feel cold

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[edit] Introductory Note

Most have felt the chill of a winter wind, the dull sting of poking a toe in icy water or the cool taste of a cough drop.But until recently, scientists haven't really understood how we feel these sensations. By tracing which neurons respond to menthol and how they react, researchers have begun to understand exactly how the body feels cold.Past work has shown that both heat and cold have counterparts in certain foods. Capsaicin, a hot molecule found in chili peppers, is known to elicit the same response in neurons as actual heat. And menthol, a flavoring agent found in mints, cough drops and some cigarettes, has been found to trigger the same sensation as real cold inside the mouth.In 1997 David Julius of the University of California in San Francisco led a team in successfully tracking down a receptor or protein on the cell's surface, known as VR1, that reacts to heat and begins a process that sends a "heat" signal to the brain.

[edit] Reason

Prior studies have suggested that cold-sensing neurons are specialized, with some detecting painful cold sensations and others detecting more pleasant ones.But now, researchers have found that the fibres lead back to one place in the neuron: a protein known as TRPM8 that relays a cold signal up the spinal cord to the brain.By following the fluorescent cold fibres, the researchers added to the evidence that TRPM8 is involved in several types of cold sensing. In teeth, the distinct nerve endings involved in the initial shooting pain and the subsequent dull ache both lead back to TRPM8, he said.Sensations such as the pleasant coolness of menthol, the sting of ice on the skin, the heightened cold sensitivity after an injury and the soothing cool of some pain relief lotions also involve TRPM8, he added.Removing TRPM8 does not eliminate all sensitivity to all types of cold. Extreme cold not only activates TRPM8 but also burns the skin, turning on many other warning circuits.Cold is going to be activating these cool and cold cells that likely are the ones we’re studying in this paper as well as activating these neurons that are probably responding to tissue damage.

[edit] Related Articles

• Why do we Sweat Even When It's Cold

• Why does one feel cold after eating

• Why do mints make your breath feel cold

[edit] More

• Medical research in the 1950s exposed 400 volunteers to cold viruses using various temperatures and conditions as variables. The result was no difference in the rate of infection between the different groups. A similar study in the late 1960s produced comparable results.

• However, some studies imply that being cold cause illness. Some arguments indicate that if you’re cold, your body is more stressed and therefore less resistant to fight a virus. Research by Cardiff University’s Common Cold Centre in Wales has proven that a drop in body temperature can cause a dormant cold virus to develop. If a person becomes chilled, for example by wearing damp clothes in cold weather, the blood vessels in the nose become constricted. When this occurs, the warm blood is closed off, no longer supplying the infection-fighting white cells.

• One study involved the effects of volunteers placing their bare feet in an empty bowl for 20 minutes or soaking their feet in a bowl containing ice-cold water for the same length of time. Within five days after the experiment, more participants who had soaked their feet in cold water developed cold symptoms than the other participants. According to the study, most likely several of those participants already had the cold virus but were not yet displaying symptoms. The lowering of body temperature was a contributing factor; in this case being cold caused illness, not the virus, but the development of the virus.

• The more likely reason that people tend to get sick more often in the winter season is the increased inside contact with others, some of whom have viruses. As the weather is chilly, people tend to stay indoors more often, making places such as schools, stores, airports and offices likely places to for catching a cold.

• People usually catch colds via the airborne droplets from a sneeze. Other methods of catching a cold are by contact from the hand to nose or eye areas after direct contact with a person who has the virus or indirect contact, such as touching the same doorknob.

[edit] References

1. why we feel cold

2. How People Feel Cold

3. Being Cold

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