Wash your hands with hot water when your hands are cold, and then your hands get hot? And very red. Why?

After the hand is frozen, the blood flow in the blood vessels at the frozen place is not smooth, and the delivered nutrients are also reduced. If you roast your hands with fire or burn your hands with hot water, the temperature of your hands will rise rapidly, and the nutrients consumed in the freezing place will suddenly increase, and the damaged blood vessels will not be unblocked immediately and a large amount of nutrients cannot be transported. Make the skin and muscles on the hands lack nutrition, which is easy to cause necrosis.

So, when your hands are frozen, don't bake them with fire or scald them with hot water. The easiest way is to gently rub your hands against each other and let them warm up slowly.