It’s almost winter where Squeaks and I live, which means it’s starting to get much colder outside!

And that means it’s time to get out our jackets and mittens and hats. Sometimes, when I get too cold, like if I forget my hat one day, I start to shiver.

Maybe that’s happened to you, too: when we shiver, we shake back and forth, and can’t stop even if we try! Shivering might not be very fun, but it’s an important way for our bodies to keep us warm. See, no matter how cold or hot it is outside, the insides of our bodies have to stay at about the same temperature all the time.

That keeps our bodies comfortable and working properly. So our bodies have built-in ways to keep our temperature pretty much the same no matter what it’s like outside. For example, if you get too hot, like if you’re running around, you’re probably going to sweat.

And that sweat helps to cool your body down. Well, shivering does the opposite of sweating: it helps to make our bodies warmer when we get too cold. Heat is leaving your body all of the time, even though you don’t usually notice it.

You know how when you have a hot bowl of soup, sometimes you can see the steam rising from it? That steam is some of the heat leaving the soup as it cools off. And the same kind of thing happens with our bodies.

We don’t give off steam, but there’s still heat leaving our bodies! When you wear a jacket or sweatshirt, the heat gets trapped between your body and the clothing. This trapped heat helps keep your body from getting too cold.

If it’s really cold outside and you’re not wearing a jacket, then there’s nothing to keep the heat from escaping into the air around you. After a while, the temperature inside of your body will start to go down a little. When it gets down far enough, you start to shiver.

I Shivering starts in a special part of your brain that controls your body temperature. Once this part of your brain gets the message from your body that you’re starting to feel pretty chilly, it sends out a message of its own to different parts of your body to fix the problem. And it sends this message without us having to do a thing.

Shivering is a good example of a reflex — something our bodies do without us having to think about them. If someone tosses a ball to you, and it’s a little too high, and headed right toward your face … look out, Squeaks! [Someone off-camera throws a ball at Squeaks. Or something else.

He ducks.] There’s a pretty good chance that you’re going to duck, and probably close your eyes, too, without even thinking about it! Ducking and bling are reflexes, and they help to protect your head and eyes from getting hurt. With the shivering reflex, your brain keeps your body from getting too cold by telling your muscles to move.

You probably already know that your muscles help your body move around. And moving muscles give off heat. That’s one reason you get hot when you exercise.

When we shiver, our muscles move in a different way than when we walk or lift something. They get tight and then loose really quickly, over and over again — they keep squeezing and relaxing. When our muscles move this way, they can make our bodies shake back and forth.

That’s shivering! Meanwhile, we usually also do other things to get warm, like put on more clothing, or wrap up in a blanket. Once our bodies get warm enough again, that special part of the brain sends a signal to the muscles to stop moving, and we stop shivering.

Of course, the best way to keep from shivering in the first place is to wear warm clothes. Wearing more than one layer is a good way to keep especially warm, because each layer can trap more heat. We can also wear mittens and hats to keep heat from escaping from our heads and hands.

All this talking about keeping warm reminds me: we need to dig our warm jackets out of the closet! C’mon, Squeaks — let’s go! Thanks for joining us on SciShow Kids!

If you have a question about something, we’d love to hear from you! Ask a grownup to help you to leave a comment below or send us an email at kids@scishow.com! We’ll see you next time, here at the Fort!