There are three kinds of ear fever. One is that you often feel hot in your ears after strenuous exercise. This is because when people exercise, their hearts beat faster and supply more blood to the muscles of their limbs. After physical exercise, muscles need less blood, but the heart can't slow down immediately, so more blood rushes to the heart. The skin of the head and ears is very thin and covered with rich blood vessels. When a large amount of blood flows through the ear, the blood vessels will expand and thicken, and the ear will turn red. Because blood has a certain temperature, ears will feel hot. After the heart gradually returned to normal, the blood vessels contracted and became thinner, and the blood volume in the ears decreased, so the fever stopped. Secondly, when the outside temperature is low, the blood vessels contract when they are cold and look pale. At this time, if you walk into a room with high temperature, the blood vessels will suddenly thicken when heated, and your ears will feel hot. Third, when you are shy, when you have a heated argument with others, or when you encounter difficulties in exams … you will feel your ears are very hot. This is because the cerebral cortex is highly excited and nervous, and the nerve instructions make the skin blood vessels dilate, the heart beats faster, and the blood flow increases faster. Since you are not shy, what are the first two reasons?