Maybe you're shivering in your sheets, while your partner slumbers away, snug as a bug, right next to you. Or perhaps you have that one relative who's always wrapped in a blanket, even when the thermostat is cranked all the way up. You might simply feel like you can never get toasty enough, no matter how many layers you toss on.
Of course, it's a common enough phenomenon. But why do some people seem to be naturally colder than others? The answer may surprise you, and it has a lot more to do with metabolism and body type than you might think.
How Humans Generate Heat
Like all mammals, humans use chemical reactions in our bodies to keep our internal temperature toasty, and consistently so. If that temperature falls just a few degrees outside of our ideal norm, we face all manner of ills, ranging from mood swings to impaired immune function — and, in extreme cases, even death.
Sometimes, our bodies deliberately try to throw off this balance. The whole point of getting a fever is to slowly cook the sickness out of your body, killing off the pathogens in the process. Even a two-degree change can cause you to feel ill, and your inner microbes to perish, during a low-grade fever.
