Have you ever stepped outside into the chilly morning air and feel your body immediately stiffen? This involuntary reaction is completely normal. And maybe an insight as to why your back may hurt on a cold winter day.

Vasoconstriction is the process of narrowing blood vessels in your extremities. This is done so that any extra blood can be diverted to more vital areas such as your brain, heart, and lungs. When the temperature drops, the body begins this process as a means to protect (and keep warm) your most vital organs. And while vasoconstriction is a preemptive measure, it means that your muscles, tendons, and ligaments have less blood. And as a result, they become stiff.