Here's The Real Reason We Shiver

The body is a well-oiled machine with processes to help keep us as safe, protected, and comfortable as possible. This phenomenon is known as homeostasis, in which the body seeks to stay in a consistent state, as explained by Mental Floss. It's so mechanical, in fact, that it even coordinates the temperature your body sits at — and shivering comes as a result of this process. 

Similar to how you sweat when your body is hot, the bodily system responds to feeling cold. You can't turn the shivers on and off — they just happen, because it's an automated response from thousands of years of evolution created to make you feel warm. By rapidly tightening and relaxing your muscles, your body is trying to heat itself up by creating friction and movement, according to Healthline. In fact, shivering can increase "your body surface's heat production by about 500 percent." However, these movements require a high amount of energy, so if you're in a cold environment for too long, your body can lose steam.

Whenever your body temperature is much warmer than the air around you, your system rapidly loses heat. In an attempt to heat up the air around you, this process can cause the shivers as body temperature declines, as noted by Mental Floss.

It's also important to note, however, that the temperature at which we shiver varies by person. This happens for a multitude of factors, including age. Children shiver more readily, since they have less body fat to "insulate" themselves from low temperatures, according to Healthline. If you're extremely sensitive to cold temperatures, shivering may be due to other reasons, such as a thyroid issue or low blood sugar. But when you get the shivers, but don't actually feel cold, it may mean something else entirely. Per Healthline, if your body is fighting off an infection, it may shiver to heat the body to temperatures high enough to "kill" the intruder. That's why, when you have a fever, you may get the shivers in conjunction with your higher temperatures.

Ultimately, shivering is a good thing that helps with vital functions like temperature regulation and fighting infections.