Even a brief walk on a frigid day can trigger an urgent “get warm!” alarm in our heads. But just how much further can we go?

When we start to get cold, our body activates a number of mechanisms to warm us back up. More specifically, a gland in our brain called the hypothalamus is activated, making our teeth chatter and our muscles shiver to produce some heat. As we get even colder, the hypothalamus redirects our blood flow to our body’s center to keep the vital organs warm. Unfortunately, this results in reduced blood circulation for our extremities (hands and feet), leaving us more susceptible to frostbite. So just how cold is too cold? We know that an extreme wind chill of negative 50 degrees Fahrenheit can cause frostbite in as little as five minutes. But the cut-off point of what is bearable remains unclear.

Experts say our temperature tolerance level depends on many factors such as our health, age, and how long we’re exposed to the cold. What to do now that winter is right around the corner, other than staying home and heating up some cocoa? Be safe! Make sure you’re dressed appropriately, and avoid prolonged exposure to cold temperatures. (There are also tons of cool tricks for cold weather – but better leave those to the experts!)