Yoinks! Do you know why your teeth chatter when you’re cold? Do you know what causes brain freeze? Have you ever jumped when somebody scared you? Let’s look at some weird things your body does, and why your body does it.
Chattering teeth — along with shaking hands and trembling legs — is your body’s way of trying to generate more heat when you’re cold. Think of it like rubbing sticks together to make fire; your body is trying to raise the temperature through movement. Shivering is also one of your body’s signals to get the antibodies moving to fight infections.
Your hair may stand on end when you’re cold, or when you’re frightened. Every hair on your body is held in place by a follicle in the skin. Sometimes, the muscle fibers connected to the follicle can contract, making the hair stand up straight. Fear, cold, or even a light touch can give you goose bumps and leave your hair standing on end. Experts believe this response is related to the fight-or-flight response of adrenaline. You may notice a dog raises his hackles (hairs on the back of his neck) when upset or a cat fluffs out her fur to look bigger. This may be a similar response!
Speaking of fear responses, you may not be the only person who jumps a mile when startled. This is another fight-or-flight moment for your body, when the adrenaline surges, increasing speed and strength. You widen your eyes to see attackers; you jump away to give yourself space to face the threat. Before your brain can consciously figure out what is going on, your body has put you into a defensive position.
Have you ever been drifting off to sleep when suddenly your body jerks, throwing you awake again? This phenomenon is known as sleep starts. Sleep experts blame this on a mistaken message in the brain: the lack of muscle tension in your body gets confused with the sensation of falling. Your body jerks the arms and legs to try and save itself.
When I was younger, we called it an “ice cream headache” — that sudden pain you get when you are eating or drinking something really cold. These days, we call it “brain freeze”. No one is one hundred percent sure WHY it happens; some experts think it may be a problem with the trigeminal nerve, located near the back of the mouth. This nerve controls all sensation to the head and face. Drinking something that’s too cold may cause the trigeminal nerve to give us that horrible sensation of pain. Some people say that pressing your tongue against the roof of your mouth can help warm up the nerve and ease the pain of brain freeze faster.