Original URL: http://www.theregister.co.uk/2006/09/08/the_odd_body_temperature/

Why do some people feel the cold more than others?

Some like it hot

By Stephen Juan

Posted in Science, 8th September 2006 15:32 GMT

Also in this week's column:

Why do some people feel the cold more than others?

Asked by Mick Higgins of Toronto, Canada

Human body temperature is a measure of the body's ability to keep, generate, or get rid of heat as the need arises. The body is very adept at maintaining temperature within a narrow and safe range, despite occasional huge variations in the room temperature.

But some bodies are more efficient than others. Even bodies of the same height and weight may differ dramatically in the ability to maintain body temperature.

Humans also differ in their preferred room temperature. Some like it warmer, some cooler. This is called thermal comfort. Thermal comfort is not merely physical, but psychological too. In one's choice of preferred temperature, besides psychology, other personal factors come into the equation. Two of these are clothing levels (their insulation value) and activity level (their effect on body metabolism).

Stephen Turner, an engineer with the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) in Atlanta, said: "Activity level is a key factor, as illustrated by the story of an adult skiing down a mountain with a child bundled in warm clothes on their back. At the bottom of the hill, the adult is sweating, but the child is bitterly cold. Difference in metabolic rate is the cause."

ASHRAE maintains and periodically revises international thermal comfort standards. But this is not the end of the story.

According to Paul Spry, a consultant engineer in Canberra, Australia, there is also evidence that a person's thermal comfort perceptions are influenced by external factors such as recent weather.

He adds: "Another consideration is the difference between sensory and psychological reactions. A particular person may say it is cold or cool, but if you accept this as the final judgment (as a desire for a higher temperature) you are at risk. Further questioning may reveal that though the person is 'cold' or 'cool' they may be optimally comfortable (desire no change for thermal comfort reasons)."

Interesting facts

Stephen Juan, Ph.D. is an anthropologist at the University of Sydney. Email your Odd Body questions to s.juan@edfac.usyd.edu.au