Why Are Some People Always Cold?

Have you ever been in a warm room, but someone in that room is still cold? Trace is joined by Julia Wilde to explain why this is.

A cold-blooded animal, or ectotherm, rely on environmental heat sources to regulate their body temperature. Warm-blooded animals (most birds and mammals) on the other hand, have the ability to maintain homeostasis independent of their environments (and tend to have higher body temperatures).

Human body temperature averages at around 98.6 degrees fahrenheit (37 celsius), while cat and dog body temperatures are closer to 101 or 102. Lions are the hottest, with a body temperature ranging from 100.5 to 102.5 degrees F (or 38.05 - 39.16 degrees C). However, within each species, body temperatures can range depending on a number of factors. In humans, women tend to run colder than men and older people tend to have colder body temperatures than younger ones.

All temperature regulation is monitored by the brain and controlled via hormones. Thermoregulator cells detect the body's core temperature, compare it to the temperature of the extremities and outer skin, and react by either constricting capillaries (through vasoconstriction, which reduces blood flow) which ultimately lowers body temperature. In contrast, vasodilation causes increased blood flow and, in turn, an increase in the temperatures of the hands and feet.

A bunch of other factors affect body temperature, too. Since fat is a good insulator, the amount of body fat a person has will result in higher average body temperature. Since men tend to have more muscle on average than women, and working muscles generates heat, the differences in average temperatures of the hands and feet between men and women can actually be pretty extreme: A study from the University of Utah found men's hands were 90 degrees F (32.2 degrees C) on average, while women's were 87.2 degrees F (30.7 degrees C). A lot of these differences could explain people who tend to "feel" cold or hot all the time.

Where are you on the spectrum? Do you find yourself complaining you're freezing all the time while everyone else thinks it's fine out? Let us know in the comments section below!

Read More:
Why are some people colder than others (via Mother Nature Network)
"Most people think the average human temperature is 98.6 degrees, but the truth is that different people have different 'normal' temperatures."

So THAT's why women's feet and hands are always cold! Why they are slaves to their hormones (Daily Mail)
"My health complaint is starting to affect my love life."

Why Do Women Often Feel Colder Than Men? (AlterNet.org)
"Let the battle of the thermostat begin. Now that the evenings have grown dark and chilly, most people have switched on their central heating."

Do Fat People Stay Warmer in Cold Weather Than Thin People? (Weather.com)?
"There may be a reason that Santa, who spends most of his time toiling away at his freezing North Pole workshop or traversing the globe in an open-air sled, is a little on the rotund side."