Why are your hands and feet cold when the weather is cold?

Cold hands and feet are generally caused by poor blood circulation, so it is recommended to exercise more.

I used to be like this. My hands and feet are often like popsicles. Later, my friend recommended me some warm tea for regulating qi and blood. I bought it from Taobao. After drinking for a while, my hands and feet are obviously much better. The weather has been cooling recently, and my hands and feet are still warm. If it used to be, it must be freezing.