When you walk out into a frigid winter's day, odds are at some point or another your teeth will start to chatter. That fast-paced opening and closing of your teeth is no accident. It's actually a mechanism the body uses to keep its core temperature of 98 degrees Fahrenheit. This is similar to the reason humans shiver. Any time skin gets too cold, receptors tell the muscles to expand and contract in quick bursts in order to produce heat. So, if you find your teeth chattering and you're shivering simultaneously, it's might be a sign that you need to warm up in the near future.
How teeth chattering works
Medical Daily notes that teeth chattering is a method of homeostasis. When your body gets too cold, the hypothalamus - the part of the brain in charge of controlling temperature - instructs your body to go into survival mode. In other words, the brain tells the body to complete certain actions as a means of generating heat. The muscles in your jaw expand and contract to create heat and cause your teeth to make noise against one another. While research suggests that slight exposure to cold temperatures can raise the body's metabolism, use shivering and teeth chattering as indicators that your body is probably colder than it should be. After all, when you're out in the snow you don't want to catch cold, or worse, end up with hypothermia or frostbite.
This is not to say you should fret every time you shiver. More so, it is a warning that you should remain cognizant of your body's natural methods of staying warm. Consciously, we can interpret these physical reactions and (ideally) make smart decisions to avoid harm.
Other jaw movements
Involuntary teeth chattering should not be confused with grinding of the teeth, as the two have distinctly different causes. Whereas chattering is the body's reaction to cold, dentists believe involuntary grinding (such as while one sleeps) is caused by excessive stress. Therefore, if you wake up in bed shivering and cold, your teeth may be chattering. However, if you wake to find that you are rigorously grinding your teeth, it's more likely a sign of stress and anxiety. In such cases, consult your dentist, as teeth grinding can lead to long-term dental problems.